Management of radiation injury

INTRODUCTION — Radiation injury can affect multiple organ systems, most notably the skin, hematopoietic system, gastrointestinal tract, and brain. Toxicity is influenced by the type and amount of radiation exposure and the nature of the exposure event.

This topic will address the management of radiation injury in adults and children. Clinical manifestations of acute radiation exposure and long-term consequences of radiation exposure and the management of victims of chemical terrorism are discussed separately.

●(See "Clinical manifestations, evaluation, and diagnosis of acute radiation exposure".)

●(See "Chemical terrorism: Rapid recognition and initial medical management".)

TYPES OF EXPOSURE EVENTS — The type of radiation exposure event influences the nature of the exposure (ie, nonionizing versus ionizing radiation), types of ionizing particles (eg, alpha particles, beta particles, neutrons) and/or x-ray/gamma rays, the amount and duration of radiation exposure, and the consequent biologic effects, as discussed separately. (See "Clinical manifestations, evaluation, and diagnosis of acute radiation exposure".)

Examples of potential exposure events include:

●Individual exposure from an industrial or medical event

●Mass-casualty incidents from:

•Transportation incident

•Nuclear reactor incident

•Nuclear detonation

•Radiologic dispersal device (RDD; ie, dirty bomb)

The type of radiation exposure event also influences the likelihood of associated injuries beyond the radiation exposure alone. For example, a nuclear detonation or RDD may involve injuries from the blast and shrapnel, burns from a fireball, or other traumatic injuries.

Additional information about types of exposure is available at https://www.remm.nlm.gov/.

PRINCIPLES OF RADIATION SAFETY — Protection from radiation exposure is primarily accomplished through [1-5]:

●Maximizing the distance from the source

●Minimizing the time of exposure

●Shielding from exposure

Maximizing the distance from the exposure source is the most effective protective strategy. For all patients with radiation exposure and/or contamination, evacuation from the source or incident site and reducing further exposure (eg, radiation fallout, contaminated soil or food, or radiation from medical imaging) are of prime importance. For contaminated patients, reduction of time of exposure is further addressed by measures to reduce internal and external contamination. (See 'Exposed and contaminated patients' below.)

Radiation incidents usually involve high-energy gamma radiation at the incident site. Effective shielding can be accomplished with lead aprons, barriers, shields, and/ or glasses. However, hospital personnel can usually achieve adequate levels of protection during the care of radiation casualties by wearing modified universal precautions consisting of disposable gowns, surgical caps, shoe covers, N-95 masks, and double gloves. (See 'Personal protective equipment' below.)

FACILITY PLANNING AND PREPARATION — Management of radiation exposure, for an individual or a community, requires knowledge of the principles of radiation safety, advance preparation, and planning at both the regional and health care facility levels. The hospital should develop a medical response plan for a nuclear or radiologic emergency as part of an all-hazards emergency management plan and ensure that it is practiced and regularly revised based upon periodic drills. This plan is required for hospital certification in many countries. Rehearsal of and familiarity with these protocols help to educate medical staff about radiation safety and their roles and responsibilities during a radiation incident. Emergency departments that are eligible to receive victims of radiation accidents must be prepared to manage large numbers of victims.

Important considerations for facility preparation for a radiation emergency are provided below but are not sufficient to serve as a detailed facility plan. Additional guidance is provided in the references [6-8]. The following resources also provide materials to assist with community, hospital, and emergency department preparation and planning for nuclear and radiologic emergencies:

●International Atomic Energy Agency

●United States Department of Health and Human Services Radiation Emergency Medical Management

●Radiation injury treatment network

●Radiation Studies Branch, Centers for Disease Control and Prevention

Radiation measurement and detection devices — The following equipment is necessary to identify and control the spread of radiation contamination [2]:

●Geiger-Mueller survey meter (also called Geiger counter) – The Geiger-Mueller (GM) survey meter detects alpha, beta, and gamma radiation and can rapidly identify the presence of contamination. Ideally, the hospital should have enough instruments to provide radiation monitoring of patients and health care providers in external triage, the external assessment and minor injury treatment area, emergency department decontamination and treatment rooms, and any other hospital sites where contaminated patients will receive care. Brief instructions for the use of a GM survey meter are provided here.

●Ionization chamber survey meters – The ionization chamber survey meters measure exposure as a function of time (eg, sievert [Sv]/hour) and can be used to determine the safe amount of time that staff can stay in close proximity to a patient who has significant contamination before they are replaced by other care providers. However, with the exception of severely contaminated patients, most individuals receiving care for a radiation emergency pose a low risk to health care workers.

●Personal dosimeter – All potential exposed hospital staff should wear a radiation dosimeter [3]. Personal dosimeters provide readings of radiation exposure for health care workers; a variety of dosimeters are available [9]. Selected devices can alarm when a preset dose limit is reached, which alerts the health care worker and radiation safety personnel to stop further radiation exposure. Some personal dosimeters can also be used as survey meters. Dose limits for emergency workers are set by government agencies. Film badges are not recommended because they do not provide real-time measurements. However, they can provide documentation of cumulative exposure if real-time dosimeters are not available. Finger ring dosimeters are also used if the dose to the hands or fingers is expected to be higher than to the torso (eg, during removal of radioactive shrapnel).

The National Council on Radiation Protection and Measurements recommends a maximum of 1 Sv (100 roentgen equivalent in man [rem]) of exposure for volunteer providers in lifesaving emergency situations and 0.25 Sv (25 rem) in less urgent situations [10]. Personnel should be rotated to minimize exposure. Pregnant personnel should be excluded from the treating team.

Multichannel devices can detect and identify specific radionuclides and may be available in hospitals that have medical physics departments.

Radiation safety personnel — Radiation safety personnel are essential for staff and patient safety during a radiation emergency [2,4]. Hospital response plans should designate a radiation safety officer who is responsible for equipment maintenance, proper training of radiation safety personnel and health care workers prior to an event, overseeing patient radiologic surveys, staff and facility monitoring of radiation levels, storage and disposal of decontaminated materials, and ensuring that contamination is eliminated during the event. Hospital staff from Departments of Radiology, Nuclear Medicine, or Radiation Oncology typically have the proper expertise to serve as radiation safety officers. Training of designated emergency department providers as members of the radiation safety team can ensure 24-hour onsite radiation monitoring capability.

In facilities with limited in-house radiation safety resources, radiation safety personnel can be accessed through a regional poison control center or the Radiation Emergency Assistance Center and Training Site (REAC/TS) at Oak Ridge, Tennessee (https://orise.orau.gov/reacts/; telephone: 865-576-1005 [emergency number] or 865-576-3131 [general information]). To obtain emergency consultation with a medical toxicologist, in the United States, call 1-800-222-1222, or the nearest international regional poison center. Contact information for poison centers around the world is provided separately. (See 'Additional resources' below.)

Personal protective equipment — While caring for patients with radiologic contamination, health care providers should always wear personal protective equipment to prevent radioactive substances from contacting or entering the body. Recommended personal protective equipment depends upon the type of hazard that is likely to be encountered. Higher levels of protection are necessary if bloodborne pathogens or chemical agents are present. Examples of personal protective equipment for first receivers of patients with chemical contamination are discussed separately. (See "Chemical terrorism: Rapid recognition and initial medical management", section on 'Protection of providers'.)

Several types of personal protective equipment are appropriate for care of radiologically contaminated patients and consist of modified universal precautions [2,4]. Typical items include:

●Shoe covers

●Zip-up coveralls (waterproof)

●Surgical cap

●Respiratory masks

●Face shield

●Inner pair of gloves

●Outer pair of gloves (different color than inner pair of gloves)

●Tape to secure outer coverings at junction of the first pair of gloves with sleeves and shoe covers with coverall pants legs

An approach to the correct donning and doffing of personal protective equipment is provided here.

Facility response — Facility response depends upon the number of expected patients and the time to their arrival. Upon notification of a radiologic emergency (mass-casualty event), receiving facilities should secure all entrances and hospital grounds, establish a security perimeter, and set up a decontamination zone that is outside the clean parts of the facility [4]. Disaster plans should be activated with broad notification of hospital personnel to ensure adequate staff and equipment to handle patient care. Facility incident command and close communication with local emergency management authorities should be established.

Unlike chemical and biologic events, radiologic contamination can be rapidly detected and is much less likely to pose a risk of serious harm to health care providers unless the patient is heavily contaminated or the hospital is in the zone of contamination [1]. Thus, hospitals should be prepared to accept radiologically contaminated patients from emergency medicine services and to encounter patients who are self-referred and potentially contaminated [2].

Well-designed plans have the following features:

●External triage site – Moving triage outside of the facility and away from the emergency department during a mass-casualty incident helps to prevent overwhelming numbers of patients from presenting directly to the emergency department, a situation that can compromise patient care for the most severely ill or injured individuals and lead to uncontrolled contamination of health care providers, equipment, and the facility [2]. Potential locations include a parking deck, pop-up awning, or tent located away from the emergency department. The triage site should permit rapid setup and have sufficient staffing, supplies, and radiation monitoring capability to sort patients by medical severity (eg, immediately life-threatening, urgent, mild or no injuries, expectant [comfort measures only]) and radiologic contamination (contaminated versus uncontaminated). (See 'Mass-casualty incident' below.)

When the hospital is expecting only one or two patients with possible radiologic contamination, triage can be accomplished in the ambulance or ambulance bay without deploying the full external triage site. (See 'Limited event' below.)

●Decontamination – Our approach to radiation patient care and decontamination is consistent with the Radiation Emergency Assistance Center/Training Site algorithm (algorithm 1).

The flow of contaminated patients should not impede care of life-threatening illness or injury but should control the further spread of radiologic contamination. All decontamination areas should permit privacy and have access to temperature-controlled water to avoid hypothermia, especially in infants, children, and older adults. A radiation safety specialist should be on hand to monitor levels of radiation and help prevent further contamination of clean areas [3,4].

The plan should explicitly direct that patients with immediately life-threatening conditions be brought directly to the emergency department resuscitation area prior to radiologic survey and decontamination [2]. These patients should be protected from further exposure by covering the face with an oxygen mask and the rest of the body with a clean sheet. The stretcher in the resuscitation room should be covered with two sheets. If time allows (eg, when given notice of arrival by emergency medical services), waterproof floor coverings can be taped to the floor of the treatment room and along a path (eg, one side of the hallway) from outside of the emergency department to the treatment room. Whenever possible, nonessential equipment should be removed from the room. Ideally, all handles, switches, and essential equipment should be covered with masking tape, paper tape, or other nonpermeable clear covering that is sealed with tape to limit the degree of room contamination.

For stable patients with serious illness or injury, radiologic decontamination consists of removal of all clothing and thorough washing of the skin and hair with lukewarm water and soap in the emergency decontamination area before the patient is brought into the clean area of the emergency department or other parts of the hospital. During mass-casualty emergencies, uninjured patients and those with minor injuries should undergo external decontamination in a site that is separate and remote from the emergency department. Essential equipment in each decontamination area includes hoses with low-flow shower nozzles, GM counters, personal protective equipment, towels, patient gowns or scrubs, sheets, and clean stretchers for patient transfer to the uncontaminated area. Plastic bags, waste containers, and lead containers must also be available for storage and disposal of contaminated material (table 1). (See 'Exposed and contaminated patients' below.)

Whenever possible, stable, contaminated patients with urgent injuries should enter the treatment facility through a separate entrance and be brought to a designated decontamination room that is separate from the rest of the emergency department [5]. The entryway should be covered with paper or waterproof sheets that are taped to the ground or floor. Areas such as autopsy rooms, casting areas, or isolated areas of the emergency department can be used. Although separation of the ventilation system from the rest of the facility is desirable, contamination through the ventilation system is very unlikely.

If a separate entrance is not available and the patient is stable, the areas traversed by contaminated patients should be taped off and labeled as radioactive [2]. A buffer zone between the contaminated and uncontaminated areas helps to prevent the spread of radioactive material. Designated personnel should remain in this area to transfer material from "clean" to "dirty" by taking uncontaminated material from the clean side and directly handing it to personnel in the contaminated area without individual-to-individual contact.

●Chelating agents for internal contamination – Hospitals that are designated as receiving centers for radiation accidents and facilities that handle radioactive materials (eg, laboratories, industry, and nuclear power plants) should have a policy to rapidly access chelating agents. For example, diethylenetriaminepentaacetic acid (DTPA) used for decorporation of radioactive plutonium, americium, and uranium may be obtained in the United States through the Customer Service Manager at Geritrex Pharmaceuticals (914-668-4003, ext. 113) and internationally through Heyl Chemisch-pharmazeutische Fabrik GmbH & Co. KG (+49 30 816 96-0). General information regarding when and how to administer these agents is available at:

•https://remm.hhs.gov/index.html

•https://www.cdc.gov/nceh/radiation/emergencies/index.htm

•https://orise.orau.gov/reacts/

•Regional poison control centers (see 'Additional resources' below)

•The National Council on Radiation Protection (report no. 161, 2010) [11]

Coordination with regional plans — An effective local medical response also requires an awareness of regional and national plans, resources, and expected role for the hospital during a radiologic or nuclear event. The hospital plan should integrate seamlessly with the regional incident command structure and promote lines of communication with key external incident leaders and responders (eg, fire department, public safety, public health, government, and military officials).

INITIAL MANAGEMENT

Approach — Essential actions during a radiation emergency include [2,4]:

●Activate the facility's emergency medical response plan and obtain the necessary radiation safety personnel (ie, staff from Nuclear Medicine, Radiation Oncology, Radiology, and Radiation Safety) or contact a regional poison control center or the Radiation Emergency Assistance Center and Training Site (REAC/TS) at Oak Ridge, Tennessee (https://orise.orau.gov/reacts/; telephone: 865-576-1005 [emergency number] or 865-576-3131 [general information]). To obtain emergency consultation with a medical toxicologist, in the United States, call 1-800-222-1222, or the nearest international regional poison center. Contact information for poison centers around the world is provided separately. (See 'Additional resources' below.)

●Deploy personal protective equipment and radiation measurement and monitoring devices; obtain a background radiation reading in the emergency department. (See 'Personal protective equipment' above and 'Radiation measurement and detection devices' above.)

●If large numbers of casualties are expected, establish a triage site external to the emergency department and the hospital (eg, ambulance bay or triage tent) and set up an external assessment center that is remote to the emergency department for decontamination and care of patients with minor injuries (eg, most ambulatory patients) and for radiation survey of uninjured individuals. (See 'Facility response' above.)

●Prioritize life-threatening and serious medical conditions over decontamination efforts; critically ill patients should be stabilized and receive lifesaving treatment, including emergency resuscitation and surgery, in the facility without delay as needed. Other patients should have serious injuries addressed before decontamination.

●Ensure radiation safety measures that limit radiation contamination and exposure of patients, hospital personnel, hospital equipment, and the facility. (See 'Radiation safety personnel' above.)

●Provide psychological support for patients and hospital staff.

All facilities should have ready access to the supplies and equipment necessary in the management of radiation accidents (table 1).

Emergency plan activation — When the hospital will be receiving patients from a radiologic incident, activation of the emergency management plan ensures that staff and resources necessary to manage patients with radiologic contamination are available. (See 'Facility planning and preparation' above.)

Staff protection — Compared with other hazards such as chemical contamination or biologic exposures, the likelihood of serious radiologic contamination of hospital staff during patient care is low, especially when proper radiation measurement and safety precautions are implemented [1,2] (see 'Radiation measurement and detection devices' above and 'Radiation safety personnel' above). For management of patients with radiologic contamination and no other potential hazards, modified universal precautions provide appropriate shielding for almost all patients. (See 'Personal protective equipment' above.)

Real-time dosimeters must be worn by health care providers to monitor their total radiation exposure [3]. Film badges are not recommended because they do not provide real-time measurements. However, they can provide documentation of cumulative exposure if real-time dosimeters are not available. The National Council on Radiation Protection and Measurements recommends a maximum of 1 sievert [Sv] (100 roentgen equivalent in man [rem]) of exposure for volunteer providers in lifesaving emergency situations and 0.25 Sv (25 rem) in less urgent situations [10]. Personnel should be rotated to minimize exposure. Pregnant personnel should be excluded from treating contaminated patients but are at no risk when treating exposed but uncontaminated patients.

Initial stabilization — Key principles for stabilization and triage include:

●Unless they have undergone a radiologic survey and decontamination prior to arrival at the receiving facility, assume all patients are contaminated.

●Life-threatening conditions that require immediate support of airway, breathing, or circulation should be addressed even before assessing the amount of radiation exposure or performing decontamination.

●Preliminary decontamination (ie, removal of clothing, washing of the victim) often begins in the field and can remove 90 to 95 percent of external contamination and limit additional radiation injury. However, not all patients may arrive after decontamination. Individuals who have been contaminated but not decontaminated in the field require resurveys before and after decontamination in the receiving facility.

●In a mass-casualty event, persons who are externally contaminated and with minor injury or uninjured should be relocated to a site remote from the emergency department for decontamination.

Hospital triage — Timely triage should establish the severity of mechanical trauma, burns, and other injuries. The nature and intensity of radiation exposure should also be estimated, if possible. Whenever possible, all triage participants should be volunteers. Health care providers should work in teams and be monitored for radiation exposure with physical dosimetry under the direction of the radiation safety officer. (See 'Staff protection' above.)

Limited event — When managing low numbers of patients from a radiologic event, emergency triage can be performed as for any other patient presenting for emergency care. However, triage should occur outside of the facility (eg, in the ambulance or ambulance bay). Patients with immediately life-threatening conditions should be brought directly to the emergency department resuscitation area for stabilization. These patients should be protected from further exposure by covering their face with an oxygen mask or face shield and the rest of their body with a clean sheet. The stretcher in the resuscitation room should be covered with two sheets. If time allows, the facility should be prepared to minimize contamination as described above. (See 'Facility response' above.)

If contaminated, stable patients should undergo decontamination in the area designated by the facility plan. Whenever possible, these patients should enter the treatment facility through a separate entrance and be brought to a designated decontamination room that is separate from the rest of the emergency department [5,12]. The entryway should be prepared to minimize contamination of patients, health care providers, equipment, and the facility. (See 'Exposed and contaminated patients' below.)

Mass-casualty incident — Upon activation of the emergency plan for a mass-casualty incident, the external triage site should be deployed. (See 'Facility response' above.)

A variety of field triage algorithms for use during a radiation emergency exist for incident management, such as Simple Triage and Rapid Treatment ("START" and "JumpSTART") or Sort, Assess, Life-saving interventions, Treatment/Transport ("SALT"). Emergency department staff should familiarize themselves with the triage guidelines used in their region. Greater detail regarding triage guidelines, including radiation triage guidelines, is available here.

In mass-casualty events, the receiving facility must triage patients according to its capabilities, with priority given to those who are likely to survive. All algorithms divide patients into the following categories:

●Immediate – Immediate casualties are those who cannot afford to wait more than a couple of minutes for treatment and are likely to survive with initial medical stabilization, decontamination, and supportive care. Impending airway compromise or respiratory distress also requires triage as immediate.

●Delayed – Delayed casualties can wait up to several hours for medical care. These patients can obey commands, are not in respiratory distress, and have peripheral pulses and no major hemorrhage but have injuries that are more than minor. Typically, these patients cannot walk without assistance.

●Minimal – Patients who meet all criteria for delayed care and have only minor injuries are considered minimal once appropriately decontaminated. These patients are typically able to walk and talk.

●Expectant/dead – Expectant patients are those who are not likely to survive given available resources. For radiologic incidents, the estimated degree of radiation exposure is an important determinant (table 2). However, exposure estimates are not typically available during the acute phase of the incident, although they may impact later decisions about advanced supportive care (eg, special treatments for hematopoietic acute radiation syndrome). (See 'Hematopoietic syndrome' below.)

Once medical classification has been assigned based upon history and, whenever possible, a survey for radiation contamination, patients should be further categorized and treated according to the following determinations [4]:

●Radiologically exposed and contaminated (externally or internally); these patients require decontamination (see 'Exposed and contaminated patients' below)

●Radiologically exposed (total or partial body exposure)

●Unexposed to radiation

The patient should be surveyed for external contamination with a handheld Geiger-Mueller (GM) probe that is covered by a clear, waterproof, plastic bag to prevent contamination; findings should be documented on an anatomic chart (figure 1A-B) [1].

For exposed patients, the dose of exposure should be estimated over the next 48 to 72 hours based upon physical findings and testing as discussed below. (See 'Estimation of radiation exposure' below.)

Exposed and contaminated patients — For all contaminated patients, it is important to intervene quickly to prevent or reduce incorporation of radioactive elements into the body, which can occur within minutes. Our approach to radiation patient care is consistent with the Radiation Emergency Assistance Center/Training Site algorithm (algorithm 1).

External contamination — All medically stable, externally contaminated patients should be brought to the designated radiation decontamination and control area. All decontamination areas should permit privacy and have access to temperature-controlled water to avoid hypothermia, especially in infants, children, and older adults. A radiation safety specialist should be on hand to monitor levels of radiation and help prevent further contamination of clean areas.

During external decontamination, the patient should have their face protected by a face shield or oxygen mask to prevent inadvertent internal contamination [1].

Clothing should be carefully removed or cut off as follows [1]:

●When taking off clothing, avoid shaking or snapping the material, which may dislodge radiation contamination into the air or back onto the patient.

●Roll clothing away from the patient and fold into the first sheet on the stretcher.

●Discard the sheet and clothing into a plastic trash bag that is marked as radioactive. Label the bag with the patient name, date, time, and the collector's name.

Once the patient is unclothed, up to 90 percent of external contamination is typically removed. At this point, the patient can undergo urgent medical assessment and treatment as needed. Once emergency treatment has been given, the patient should undergo a whole-body radiologic survey [13]. Contaminated areas should be marked in permanent marker and recorded on a radiation contamination assessment form.

Further decontamination is performed in the following order [1,12,13]:

●First, decontaminate open wounds – Contaminated wounds can lead to rapid incorporation of radioactive substances into the body and are a high priority. Embedded metallic fragments can be highly radioactive and should be removed with tongs or forceps rather than the fingers (to increase the distance to the exposure source) [14]. "Hot" particles are microscopic particles that can be highly radioactive and difficult to detect and/or dislodge, but such particles can sometimes be localized by placing a thick piece of lead between the suspected site and the radiation detector; if the particle is properly localized, the radiation count should decrease. Localized particles can usually be removed by mechanical means, although sometimes punch biopsy of the skin is necessary. Debris from wounds should be stored in lead containers and surveyed for radioactivity.

Once radioactive shrapnel or other foreign bodies are removed, these wounds should be managed similarly to infected wounds with some modifications; the area around the wound should be cleansed and covered with waterproof surgical drapes. The wound should be gently irrigated with lukewarm water or normal saline, and the runoff captured in a waterproof container that is marked as radioactive. Vigorous scrubbing should be avoided. Liquid materials from the wound should be removed by blotting once with sterile gauze, discarding the contaminated dressing, and repeating as needed. To obtain accurate results, contaminated drapes and dressings should be removed before each episode of monitoring [15]. The wound is surveyed again to determine if all contamination has been removed.

Contaminated burns should be treated as any other thermal or chemical burn [5]; contaminants may slough off with the burn eschar. Thus, dressings and bed linens should be considered contaminated [15].

●Next, survey and decontaminate the face and facial orifices (eyes, nose, mouth, and ears) – With a cotton-tipped applicator, gently swab the ears, nose, and mouth and survey for radioactivity. The mouth, nose, eyes, and ears require special attention in decontamination because of the potential for more rapid absorption of radioactive material from these sites [12,15]:

•Frequent mouth rinsing and tooth brushing with toothpaste are encouraged if radioactive material has entered the oral cavity; gargling with a 3 percent hydrogen peroxide solution also may be helpful.

•The eyes should first be evaluated for open globe and intraocular foreign bodies. (See "Open globe injuries: Emergency evaluation and initial management", section on 'Initial emergency assessment and treatment'.)

Irrigation is then performed as for chemical exposures with collection and proper disposal of irrigation fluid (see "Topical chemical burns: Initial evaluation and management", section on 'Patient with eye exposure'). The eyes should be rinsed by directing a stream of water from the inner canthus to the outer canthus. Care should be taken to avoid contamination of the nasolacrimal duct.

•If the auditory canals have been contaminated and the tympanic membrane is intact, an ear syringe can be used to rinse the auditory canal.

•For nasal contamination, the patient should blow their nose followed by gentle lukewarm saline irrigation with the patient leaning forward; swallowing must not occur to prevent internal contamination.

●Finally, decontaminate intact skin and hair – Decontamination of intact skin should proceed from areas with highest to lowest radioactivity. Clean wounds should be covered with waterproof dressings to avoid contamination during irrigation. Decontamination should be performed with sponging of lukewarm water and a mild soap; cold water should be avoided because it closes the pores and can trap radioactive materials, while hot water should be avoided because it opens the pores and causes vasodilation, increasing the risk of absorption [15]. Care should be taken to avoid further abrasion or erythema of the skin, which also may increase absorption [1,2,13]. Areas that are sponged should be resurveyed frequently until the counts are consistent with background levels (eg, two to three times background level) or decontamination results in no further decrease in radiation measurements.

Hair may need to be clipped if washing is insufficient for decontamination; it should not be shaved because shaving may cause open wounds and internal incorporation of radioactive substances. Liquids and materials used for decontamination should be stored in marked containers for disposal.

After decontamination, the patient should be dried and placed on a clean stretcher or in a wheelchair that is pushed by an individual who was not involved in the decontamination. The patient can then be evaluated by emergency department personnel for further care [2].

All equipment used in decontamination should be surveyed before leaving the decontamination area. Individuals who leave the decontamination area should follow a clearly marked path in order to minimize cross-contamination. Personnel leaving the decontamination area should deposit all gloves, masks, hats, scrub suits, and shoe covers into marked, designated receptacles before leaving. The radiation safety specialist should collect dosimeters after they have been labeled with appropriate identifying information [1,2,13].

Once patient decontamination is complete, all tape and protective coverings should be removed and disposed of in labeled bags, and the area should be rechecked. As they exit the decontamination room, decontamination personnel enter the buffer zone, where they remove their outer protection, turning the garments inside out. They label their dosimeter badges and turn them in to the radiation officer [3]. When decontamination is complete, the radiation safety inspector performs a final sweep of the entrance, the transferring area, the buffer zone, and the treatment area to ensure that no excessive radiation remains before the treatment team leaves the contamination area.

Internal contamination — Nasal swabs and excreta (urine and feces) should be examined for radioisotopes to detect internal contamination via ingestion, inhalation, or absorption through the skin or mucous membranes [12]. If the radiation incident involved an explosion or fire, inhalation of radioactive material should be assumed. Patients with external contamination who have undergone endotracheal intubation are also considered to have internal contamination. Clothing should be placed in labeled bags, and equipment used to transport or care for the patient should remain separate and can be surveyed for radiation and decontaminated if necessary.

If internal contamination has occurred or is suspected, samples of feces, urine, wound secretions, or emesis should be obtained as soon as possible upon arrival to the treating facility. Urine and feces should continue to be tested for four days [3]. If internal contamination has occurred, urine and feces may contain radioactive material, creating a potential contamination hazard, and appropriate precautions must be taken. Any patient with wound contamination or who has imbedded radioactive fragments should undergo evaluation for internal contamination. The swabs should be placed in bags, labeled with the anatomic collection site, and assessed for radioactivity with a GM counter or alpha-radiation detection device. Hospital staff must take appropriate precautions while handling these samples as they may be radioactive.

Management of internal contamination varies with the radioactive element and its chemical form. Isotope identifiers are available from state radiation departments, National Guard Civil Support Teams, and some hazardous materials (HAZMAT) units. Absorption can be prevented by binding the substance in a resin or forming a complex with it, reducing absorption from the bowel, and/or facilitating elimination by decreasing bowel transit time or forcing diuresis [1-3,5]. Information regarding these agents, as well as expert guidance about the management of internal contamination, is available at https://orise.orau.gov/reacts/, the National Council on Radiation Protection [11], poison control centers, or by calling REAC/TS at its 24-hour emergency number (865-576-1005). In the United States, consultation with REAC/TS is sometimes necessary before the US Food and Drug Administration (FDA) will release certain medications for management [3].

Examples of radioactive isotopes and potential medications to prevent or reduce internal contamination include:

●Radioactive iodine – Patients who were potentially exposed to radioactive iodine may be treated with supersaturated potassium to block thyroid deposition. Potassium iodide is most effective when administered soon after exposure. For this reason, it may be stockpiled near sites at heightened risk (eg, within a 10-mile radius of nuclear power plants) [5,16,17]. When administered immediately before and 2, 8, and 24 hours after exposure, potassium iodide prevents 100, 80, 40, and 7 percent, respectively, of the radioiodine deposition [18]. A single dose provides protection for approximately 24 hours [19]. (See "Radiation-induced thyroid disease", section on 'Potassium iodide for thyroid protection in a nuclear accident'.)

The treatment with potassium iodide is prioritized by age with infants, children, and pregnant and breastfeeding women given priority due to their heightened risk of thyroid cancer [19]. Repeated doses of potassium iodide should be avoided in neonates and pregnant women; these patients should be prioritized for evacuation away from further exposure.

More information on dose and available preparations (including instructions on how to mix the tablets with food or drink to make them palatable for infants and small children) can be found at the FDA website and the Centers for Disease Control and Prevention. (See "Radiation-induced thyroid disease", section on 'Potassium iodide for thyroid protection in a nuclear accident'.)

●Cesium, rubidium, thallium – Prussian blue (ferrihexacyano-ferrate II) should be administered to patients contaminated with substances such as cesium-137, rubidium-82, or thallium-201 to prevent recycling of the radioactive substance [3].

●Plutonium, yttrium – Patients with potential incorporation of the transuranics (eg, plutonium-239 or yttrium-90) can receive calcium or zinc diethylene triamine penta-acetate (DTPA) for chelation [3].

●Uranium – Sodium bicarbonate can be helpful in alkalinizing the urine of patients contaminated with uranium to reduce the risk of acute tubular necrosis [3].

●Strontium – Oral calcium or aluminum phosphate solutions can block the absorption of strontium through competitive inhibition [3].

Exposed patients (no contamination) — Patients exposed to radiation but who are not contaminated pose no contamination risk to others [1,2]. These patients warrant evaluation and further care per the Radiation Emergency Assistance Center/Training Site algorithm (algorithm 1).

The predominant clinical manifestations and severity of injuries should inform the decision to monitor and manage an individual as an outpatient, inpatient, or in a specialized center (eg, burn unit, transplantation unit) (algorithm 2). In some cases, management decisions for high-risk individuals must be made before all results of the assessment of radiation injury are available. (See "Clinical manifestations, evaluation, and diagnosis of acute radiation exposure", section on 'Estimation of radiation exposure'.)

Patients with grade ≥2 hematologic toxicity (table 3) or grade ≥3 cutaneous (table 4), gastrointestinal (table 5), or cerebrovascular (table 6) toxicity should be hospitalized. Most patients with grade ≥3 hematologic toxicity should be managed in a critical care setting, such as a transplantation unit or intensive care unit, while those with grade ≥3 cutaneous complications may benefit from management in a specialized burn unit. In addition, patients with trauma and radiation exposure have a "combined injury" with a worse prognosis than the same level of trauma or radiation exposure alone, which may elevate the anticipated medical support needed [20].

Patients who are known to have received a lethal dose of gamma radiation (eg, ≥10 gray [Gy]) or with multiorgan failure should receive pain control, antiemetics, antiepileptics, and other aspects of palliative care in a proper inpatient or outpatient setting.

Unexposed patients — For patients whose evaluation found no evidence of radiation exposure, management should be based on the nature and extent of other injuries. Unless other physical injuries require hospitalization, the patient can generally be discharged for outpatient follow-up. All patients, including those who have insignificant or no exposure, may have significant psychosocial needs, and reassurance and counseling should be offered to all individuals [4].

It is important to recognize that even if a patient did not suffer radiation injury or other trauma, anxiety from being present at a radiation exposure event or witnessing other patients' injuries may cause significant psychological trauma. Fear that is out of proportion to the actual danger is common and is fostered by misconceptions about the health effects of radiation [5]. Anxiety is increased because exposure to ionizing radiation cannot be perceived by the affected individual, and the onset of symptoms is generally delayed. Emotional stress and anxiety caused by perceived radiation exposure may cause nausea, vomiting, and/or diarrhea that can be indistinguishable from effects of radiation exposure.

Guidance for psychological and emotional issues encountered during radiation emergencies is available here [21].

ESTIMATION OF RADIATION EXPOSURE — The clinical manifestations, diagnosis, and evaluation of acute radiation exposure are discussed in detail separately. (See "Clinical manifestations, evaluation, and diagnosis of acute radiation exposure".)

For patients with suspected radiation exposure, initial laboratory studies should include:

●Complete blood count (CBC) with differential; the time of CBC collection must be carefully noted because of important time-related changes in the lymphocyte count (table 3). Serial CBCs should be obtained every 6 to 12 hours for at least three samples, and then once daily.

●Chemistries (eg, electrolytes, renal and liver function tests) should be monitored daily unless the patient's clinical condition requires more frequent monitoring.

●Baseline prothrombin time (PT), partial thromboplastin time (PTT), type and screen, and urinalysis.

●Twenty-four hours after any significant exposure, a blood sample should be drawn into a lithium heparin tube and sent to an appropriate referral lab for chromosomal aberration analysis for assessment of prognosis.

●For some patients with evidence of substantial radiation exposure (eg, aplasia, early onset of mental status changes, vomiting, or skin burns), blood for human leukocyte antigen (HLA) typing should be obtained before the lymphocyte count falls, in the event that hematopoietic stem cell transplantation may be required.

Blood studies should be drawn from an uncontaminated skin area. All samples should be labelled as radioactive before sending for analysis.

Assessment of the extent of radiation injury based upon physical findings and laboratory studies can help to determine the most appropriate site for evaluation and management. There is no consensus regarding the optimal tool for assessment of radiation injury, and no studies have directly compared various models. Consultation with physicians who have expertise in radiation biodosimetry (eg, nuclear medicine or radiation oncology specialists), whenever available, is advised.

In facilities with limited in-house radiation safety resources, radiation safety personnel can be accessed through a regional poison control center or the Radiation Emergency Assistance Center and Training Site (REAC/TS) at Oak Ridge, Tennessee (https://orise.orau.gov/reacts/; telephone: 865-576-1005 [emergency number] or 865-576-3131 [general information]). To obtain emergency consultation with a medical toxicologist, in the United States, call 1-800-222-1222, or the nearest international regional poison center. Contact information for poison centers around the world is provided separately. (See 'Additional resources' below.)

We suggest use of an assessment and management tool based upon the Medical Treatment Protocols for Radiation Accident Victims (METREPOL) [22] in the first 48 hours after radiation injury, which uses the timing, type, and severity of clinical findings to stratify patients for further evaluation and management [23]. METREPOL provides tools for diagnosis and triage of persons exposed to radiation in small- and medium-sized radiation accidents; it was not developed to address triage and management in very large incidents.

An acceptable alternative approach for patients who have been exposed to whole-body radiation is to evaluate the severity of injury to various organ systems and estimate the biodose based on clinical and laboratory findings:

●Response category – Response is assigned based on the severity of clinical findings of skin (table 4), gastrointestinal tract (table 5), cerebrovascular system (table 6), and hematologic system (table 3 and algorithm 2).

●Radiation biodose – Radiation biodose (ie, severity of exposure to ionizing radiation) may be estimated based on the time of onset of vomiting, dynamics of the absolute lymphocyte count, and extent of chromosomal abnormalities (table 7). The United States Armed Forces Radiobiology Research Institute has developed the Biological Assessment Tool to integrate these clinical, laboratory, and dosimetric data [24,25]. A version of this tool is available at the United States Department of Health and Human Service Radiation Emergency Medical Management (REMM) website.

The Radiation Injury Treatment Network has also developed general guidelines for assessment and management of hematopoietic injury [26].

ONGOING MANAGEMENT

Partial-body exposure — In acute partial-body exposure, one part of the body receives the majority of exposure. This type of injury comprises the majority of gamma radiation exposure incidents (eg, from industrial accidents in which radioactive sources were handled inappropriately). Decontamination should be performed as needed (ie, if the patient was also exposed to alpha or beta particles). (See 'Exposed and contaminated patients' above.)

The skin is the area most commonly involved, and management depends on the severity of the exposure. (See 'Cutaneous syndrome' below.)

Acute radiation syndrome

Multidisciplinary management — Management of acute radiation syndrome is best provided by a multidisciplinary team. Depending on the findings from the clinical evaluation and screening laboratory studies (algorithm 2), a trauma surgeon, burn specialist, dermatologist, gastroenterologist, neurologist, and/or hematologist may participate in care. Information regarding risk level should be provided to medical caregivers by the medical center's radiation safety officer. Consultation with experts in radiation accident management is encouraged and is available through the Radiation Emergency Assistance Center and Training Site (REAC/TS) at https://orise.orau.gov/reacts/; telephone: 865-576-1005 (emergency number) or 865-576-3131 (general information) [15].

Manifestations of acute radiation syndrome (ARS) are discussed separately (see "Clinical manifestations, evaluation, and diagnosis of acute radiation exposure", section on 'Clinical manifestations'). Over time, each patient should be stratified according to the severity of clinical findings (table 3 and table 4 and table 5 and table 6) and estimated radiation exposure.

Hematopoietic syndrome — Management of hematopoietic radiation injury may require a multidisciplinary team, including hematologist/oncologists, radiation oncologists, physicians skilled in hematopoietic cell transplantation, and other medical specialists [26-28]. Disposition to an outpatient, inpatient, or specialty center (eg, transplantation unit) setting is informed by the severity of the injury (algorithm 2), as described above. (See 'Exposed patients (no contamination)' above.)

Stratification of care — Management of hematopoietic toxicity is stratified according to the degree of myelosuppression as determined by complete blood count with differential and signs of bleeding (table 3). (See "Clinical manifestations, evaluation, and diagnosis of acute radiation exposure", section on 'Estimation of radiation exposure'.)

Treatment of radiation-induced hematologic toxicity should consider the severity of hematopoietic injury, age and medical fitness, other radiation-induced organ toxicity, the presence of combined injury (burns or trauma), and institutional resources:

●Grade ≤1 without other toxicity/adverse features – For grade ≤1 (estimated ≤3 gray [Gy] exposure) with no other radiation-induced organ toxicity, thermal burns, or trauma, the patient can generally be managed as an outpatient; no specific hematologic intervention is needed.

●Grade ≤1 with other toxicity/adverse features – For grade ≤1 with combined injury (eg, burns or trauma), age ≤12 years, or age ≥60 years, hospitalization is warranted due to increased risk for hematopoietic toxicity; if myelosuppression occurs, it is typically manageable with cytokine therapy and supportive care.

●Grade 2 – For grade 2 (estimated >3 to ≤7 Gy exposure), the patient should generally be hospitalized, and toxicity is typically manageable with prompt use of hematopoietic cytokines and aggressive supportive care. (See 'Supportive care for hematopoietic ARS' below.)

●Grade 3 or 4 – For grade 3 to 4 (estimated >7 to ≤10 Gy exposure), the patient should be hospitalized (ideally in a transplantation or other specialty unit) to receive aggressive supportive care and may benefit from allogeneic hematopoietic cell transplantation (HCT). (See 'Hematopoietic cell transplantation' below.)

●Grade 4 – For grade 4 toxicity in patients with estimated exposure >10 Gy, radiation injury is likely to be fatal due to multiorgan failure (eg, cerebrovascular and gastrointestinal toxicity), and care should be directed at palliation of symptoms.

These suggestions are consistent with those of the World Health Organization, American, and European expert panels [27,29-31].

Supportive care for hematopoietic ARS — The clinician should obtain consultation from specialists who have expertise in the assessment and management of hematopoietic ARS (eg, hematologists, radiation oncologists, and/or radiologists). For patients who were exposed to <7 Gy radiation, hematopoietic ARS can generally be managed with supportive care, including transfusions, growth factors (cytokines), and management of infections.

Hematopoietic failure in irradiated victims is managed with the same principles used to manage other patients with pancytopenia, with the recognition that symptoms requiring treatment (eg, bleeding, anemia) may not develop until 21 to 30 days after exposure [14]. (See "Treatment of aplastic anemia in adults", section on 'Supportive care'.)

●Transfusion support for anemia and/or thrombocytopenia – Blood product support may be required for management of cytopenias from radiation-induced bone marrow suppression and/or bleeding (eg, gastrointestinal and other blood loss). Guidelines for transfusion of red cells and platelets should follow those recommended for patients recovering from chemotherapy (table 8). (See "Indications and hemoglobin thresholds for RBC transfusion in adults" and "Platelet transfusion: Indications, ordering, and associated risks", section on 'Indications for platelet transfusion'.)

If time and resources permit, all cellular blood products should be:

•Leukoreduced and/or pathogen-reduced – Leukoreduction can lessen febrile nonhemolytic transfusion reactions and the immunosuppressive effects of blood transfusions. (See "Red blood cell transfusion in infants and children: Selection of blood products", section on 'Leukoreduced red blood cells' and "Practical aspects of red blood cell transfusion in adults: Storage, processing, modifications, and infusion", section on 'Pre-storage leukoreduction' and "Platelet transfusion: Indications, ordering, and associated risks", section on 'Leukoreduction'.)

•Irradiated or pathogen-reduced - Irradiation (ie, 25 Gy) or techniques for pathogen-reduction prevent transfusion-associated graft-versus-host disease (ta-GVHD), which can be life-threatening in immunosuppressed patients. Ta-GVHD is almost uniformly fatal, and the fever, pancytopenia, skin rash, diarrhea, and abnormal liver function may be difficult to distinguish from other organ toxicities seen in victims of radiation injury. (See "Transfusion-associated graft-versus-host disease", section on 'Methods to inactivate viable T cells'.)

●Cytokines – Cytokine support for patients who experienced substantial radiation exposure and/or hematopoietic toxicity should be given as soon as possible after suspected or confirmed exposure (preferably <24 hours) [27,29]. The levels of exposure/hematopoietic injury for which cytokine support is warranted are described above. (See 'Stratification of care' above.)

•Myeloid cytokine – For patients with grade ≥3 hematologic toxicity or with suspected or confirmed radiation exposure ≥2 Gy, we recommend treatment with a myeloid cytokine (eg, granulocyte colony-stimulating factor [G-CSF], granulocyte-macrophage colony-stimulating factor [GM-CSF]). This recommendation is based on faster neutrophil recovery and possible improved survival according to case series and individual case reports of victims of radiation accidents [31-33].

Details of cytokine dosing and administration are provided here [34]. Cytokine therapy may be associated with increased adverse effects in patients with sickle cell disease, significant coronary artery disease, and acute respiratory distress syndrome. (See "Introduction to recombinant hematopoietic growth factors", section on 'Toxicity of colony-stimulating factors'.)

•Add romiplostim to myeloid cytokine – For the population described above (ie, grade ≥3 hematologic toxicity or ≥2 Gy exposure), we suggest adding romiplostim (which is thought to enhance hematopoietic stem and progenitor cell recovery) to a myeloid cytokine.

Romiplostim has not been evaluated in humans with radiation injury, but it is beneficial for treatment of aplastic anemia and refractory immune thrombocytopenia. In nonhuman primates exposed to toxic levels of radiation, treatment with romiplostim alone, pegfilgrastim alone, or romiplostim plus pegfilgrastim was associated with superior overall survival (OS; 100 versus 45 percent OS at day 45) and improved hematologic parameters compared with untreated controls [35]. OS at day 60 was 73 percent for romiplostim alone, 88 percent for romiplostim plus pegfilgrastim, and 33 percent for controls [36].

Romiplostim doses ≥10 mcg/kg in humans have been associated with grade 3 hepatotoxicity, mild headache, and muscle spasms. (See "Clinical applications of thrombopoietic growth factors", section on 'Romiplostim (Nplate, Romiplate)' and "Treatment of aplastic anemia in adults", section on 'Refractory AA'.)

Romiplostim is approved by the US Food and Drug Administration (FDA) for treatment of adults and children (including neonates) who are acutely exposed to myelosuppressive doses of radiation [37].

Cytokine therapy should begin promptly (based on level of injury/exposure) and should not be delayed if a complete blood count (CBC) is not immediately available. Treatment should continue until the absolute neutrophil count (ANC) is ≥1000/microL. Cytokines are most beneficial in patients with an absorbed dose of <5 Gy [31]. Depending on radiation dose, the neutrophil count may rise steadily, or cytopenias may improve only transiently, causing an "abortive rise" in neutrophil count.

•Limited role for erythropoiesis-stimulating agents (ESA) – As discussed above, blood transfusions are the primary therapy for anemia caused by acute radiation syndrome. A benefit has not been proven in this setting for recombinant ESA (eg, erythropoietin alfa, darbepoetin). A weak recommendation for the use of ESAs was made by the World Health Organization panel of experts [30]. Use of ESAs is discussed separately. (See "Role of erythropoiesis-stimulating agents in the treatment of anemia in patients with cancer", section on 'Formulations and dosing'.)

●Infection prevention – Radiation injury causes susceptibility to local and systemic infection due to immune suppression, neutropenia, and breaches in cutaneous and mucosal barriers. Bacterial infections are the most common cause of infections in this setting, but individuals are also at risk for fungal and viral infections. Susceptibility to infections rises with ANC <500/microL and longer duration of neutropenia (table 9 and figure 2).

Patients with fever (ie, ≥38.0°C [100.4°F]) or other evidence of infection and neutropenia (ANC <500/microL) should receive empiric broad-spectrum intravenous antibiotics within 60 minutes of triage and at full doses, adjusted for renal and/or hepatic function. A diagnostic evaluation should be obtained quickly but should not delay administration of empiric antibiotic treatment. Recommendations for management, including antibiotic choice, are described separately. (See "Treatment of neutropenic fever syndromes in adults with hematologic malignancies and hematopoietic cell transplant recipients (high-risk patients)", section on 'Empiric therapy'.)

For afebrile/asymptomatic individuals with ANC <500/microL, prophylactic broad-spectrum antibiotic therapy (eg, a fluoroquinolone) should be given until the patient develops a fever (or otherwise fails treatment), develops toxicity, or neutrophils recover to ANC >500/microL. Prophylaxis is discussed separately. (See "Prophylaxis of infection during chemotherapy-induced neutropenia in high-risk adults" and "Prophylaxis of invasive fungal infections in adults with hematologic malignancies".)

Hematopoietic cell transplantation — HCT is not generally recommended for the management of patients with hematopoietic syndrome; it should be offered to only those individuals who have failed to improve hematologically after ≥2 weeks of supportive hematologic care (eg, cytokine therapy and transfusions) and who have no serious injury to other organ systems (eg, gastrointestinal [GI], neurovascular, or cutaneous systems) and have a suitable donor [30,31]. There is no consensus regarding specific guidelines for use of HCT in this setting, and a decision to proceed with transplantation must be individualized based upon severity of injuries, comorbid illnesses, graft availability, adequate medical infrastructure, institutional practice, and patient preference. This decision should weigh the benefits of hematopoietic recovery and immune reconstitution against the risks of graft-versus-host disease (GVHD) and other transplant-related toxicity. It is strongly influenced by the level of radiation exposure. Patients exposed to >7 to <10 Gy are most likely to benefit from allogeneic HCT. For patients with lower levels of exposure and toxicity, transfusion, cytokines, and management of infectious risks may be sufficient, whereas patients with >10 Gy exposure are likely to die from multiorgan failure independent of hematopoietic toxicity.

A well-matched sibling or unrelated donor is the preferred graft source, but alternative sources (eg, umbilical cord blood, haploidentical donor) may expand the pool of candidates for allogeneic HCT in this setting. For some patients a syngeneic (ie, identical twin) or autologous graft (eg, certain at-risk military personnel who had cells stored for emergency purposes, patients with stored stem cells as a potential backup for treatment of a prior malignancy, patients with their own umbilical cord blood in long-term storage) is available.

Existing evidence suggests that the outcome of HCT for hematopoietic syndrome is poor. Review of HCT in three radiation accidents reported that most transplant recipients developed nonhematopoietic organ failure. A separate review of radiation incident registries indicated that, of 31 patients who underwent HCT, 27 patients died and the remaining four patients survived with a rejected allograft [30].

Given the similarities between patients with hematopoietic radiation injury syndrome and those undergoing hematopoietic cell transplantation, many of the fundamentals in supportive care, prophylaxis, blood product support, and infection management remain the same. (See "Prevention of infections in hematopoietic cell transplant recipients" and "Hematopoietic support after hematopoietic cell transplantation" and "Overview of infections following hematopoietic cell transplantation".)

Gastrointestinal syndrome — Manifestations of GI ARS are influenced by the nature and extent of the exposure and may include diarrhea, abdominal cramps and pain, GI bleeding, life-threatening electrolyte disturbances, and infections (table 5). (See "Clinical manifestations, evaluation, and diagnosis of acute radiation exposure", section on 'Gastrointestinal'.)

Aggressive fluid resuscitation with frequent monitoring of serum chemistries and fluid balance is crucial for patients with GI syndrome because life-threatening electrolyte disturbances may occur. Further GI losses should be managed with prophylactic antiemetics (eg, ondansetron) and, for severe diarrhea, loperamide [30]. Consultation with gastroenterologists should be obtained, and parenteral nutrition should be initiated to promote tissue anabolism. Prophylactic antibiotics (eg, fluoroquinolones) are indicated for the first two to four days after radiation exposure [30]. Subsequently, antibiotics are necessary for treatment if bacteremia develops. Despite these measures, irreversible septic shock remains the overwhelming cause of death in severe GI ARS.

Central nervous system syndrome — Patients exposed to doses of radiation that are high enough to cause severe (eg, grade 3 to 4) central nervous system (CNS) syndrome (eg, impaired consciousness, seizures) have an extremely poor prognosis. Manifestations of the neurologic ARS are described separately. (See "Clinical manifestations, evaluation, and diagnosis of acute radiation exposure", section on 'Neurovascular syndrome'.)

Management should focus on symptom relief (eg, headache, other pain, delirium), treatment of increased intracranial pressure caused by diffuse cerebral edema, and avoidance of factors that might exacerbate the neurologic deficits. (See "Delirium and acute confusional states: Prevention, treatment, and prognosis", section on 'Management' and "Evaluation and management of elevated intracranial pressure in adults" and "Elevated intracranial pressure (ICP) in children: Management".)

Cutaneous syndrome — Cutaneous ARS ranges from transient erythema and pruritus to blistering, ulceration, and sloughing of skin, depending on the nature and extent of exposure (table 4); ie, whole body versus partial body. The extent of cutaneous injuries should be carefully documented (figure 1A and figure 1B). (See "Clinical manifestations, evaluation, and diagnosis of acute radiation exposure", section on 'Cutaneous'.)

Management depends on the severity and the extent of the exposure:

●Minor cutaneous injury is described separately. (See "Treatment of minor thermal burns".)

●Patients who received partial-body doses <5 Gy usually have damage limited to erythema, severe xerosis, vesiculation, and loss of hair with eczematous changes that may be permanent. These injuries may need to be treated at a burn center, and healing may take one to two months.

●For patients who received doses ≥5 Gy, wet gangrene and ulceration may develop due to damage to the underlying vasculature and connective tissue. For patients with severe and/or extensive cutaneous ARS, care may be most effectively delivered by a multidisciplinary team (eg, burn specialists, dermatology, plastic surgery, orthopedists, occupational and physical therapists, and psychologists) in a specialty burn unit. (See "Overview of the management of the severely burned patient" and "Emergency care of moderate and severe thermal burns in adults" and "Moderate and severe thermal burns in children: Emergency management".)

FOLLOW-UP — There is no optimal schedule of follow-up for all patients after radiation injury, and monitoring should be individualized based on the manifestations and complications of radiation injury and should respond to the concerns of the individual. While acute radiation syndrome (ARS) is typically resolved within the first two months, monitoring for long-term sequelae (eg, cancer surveillance) should be implemented.

Victims of radiation accidents experience a great deal of psychologic stress related to perceived radiation injury and concern about future cancer risk [5]. All victims, regardless of the degree of exposure, should have follow-up arranged with providers who can address these concerns (eg, environmental health or radiation specialists, psychologists, primary care clinicians).

Children who received radiation exposure to the thyroid gland should have their thyroid glands checked regularly. The frequency and method of follow-up of irradiated patients depends upon their estimated risk and the clinical findings at the initial evaluation. (See "Radiation-induced thyroid disease", section on 'Surveillance for structural thyroid abnormalities'.)

Patients with ocular exposure, particularly to neutron radiation, should undergo regular examination for cataract development [38]. (See "Cataract in children", section on 'Clinical features'.)

PEDIATRIC CONSIDERATIONS — The approach to initial and ongoing management of children with radiation injury is similar to adults, with a few notable exceptions [19,39]:

●Whenever possible, children should be kept with their caregiver or close relative throughout their medical care to provide reassurance and to decrease psychological stress.

●During decontamination, children, especially infants and preschool children, are prone to hypothermia and warrant frequent monitoring of core body temperature.

●Special dosing is necessary for potassium iodide to block thyroid incorporation of radioactive iodine in neonates, breastfeeding infants, older infants, and children. (See 'Internal contamination' above.)

●Internal decontamination may be harder to document in infants and children because of the difficulty in obtaining accurate 24-hour urine and fecal samples and because the radiation detection device must be recalibrated for smaller body size.

●Depending on age, pull-ups or diapers may need to be collected and measured for radiation contamination. Nasogastric tube placement for bowel irrigation may be needed as children are unlikely to tolerate the amounts of solution necessary.

●Clinical Decision Guide values for use of blocking or chelating agents, other than potassium iodide, should be 20 percent of adult values because of increased radiosensitivity in infants and children.

ADDITIONAL RESOURCES — Further guidance on the management of radiation exposure is available as follows:

United States and international organizations

●United States Health and Human Services: Radiation Emergency Medical Management – This website provides comprehensive guidance on diagnosis and treatment of a wide variety of radiation emergencies, including nuclear reactor accidents, nuclear explosions, and radiological dispersal devices (eg, radiologic dispersal device [RDD]/dirty bomb) at https://remm.hhs.gov/index.html.

●Oak Ridge Institute for Science and Education – Hospital triage and medical aspects of radiation incidents, including detailed procedure demonstrations for decontamination, are available at https://orise.orau.gov/resources/reacts/index.html.

●US Food and Drug Administration (FDA) – Information on dose and available preparations (including instructions on how to mix the tablets with food or drink to make them palatable for infants and small children) can be found at https://www.fda.gov/drugs/bioterrorism-and-drug-preparedness/potassium-iodide-ki.

●World Health Organization (WHO) – WHO maintains a website that provides useful information and documents for download in the event of an international radiation accident or emergency. The WHO report on national stockpiles for radiological and nuclear emergencies can be found here.

Regional poison control centers — In the United States, regional poison control centers are available to provide radiation exposure information and resources (eg, access to local radiation safety officers). To obtain emergency consultation with a medical toxicologist, in the United States, call 1-800-222-1222. In addition, some hospitals have medical toxicologists available for bedside consultation. Contact information for poison centers around the world is provided separately. (See "Society guideline links: Regional poison control centers".)

Society guideline links — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Radiation exposure in children".)

SUMMARY AND RECOMMENDATIONS

●Facility planning and preparation – Successful management of radiation exposure, for an individual or a community, requires knowledge of the principles of radiation safety, advance preparation, and planning at both the regional and health care facility levels. Our approach to radiation patient care and decontamination is consistent with the Radiation Emergency Assistance Center/Training Site (REAC/TS) algorithm (algorithm 1). (See 'Facility planning and preparation' above.)

●Initial facility actions – Essential facility actions during a radiation emergency include (see 'Initial management' above):

•Activate the facility's emergency medical response plan and obtain the predesignated facility radiation safety personnel (ie, predesignated facility staff from Nuclear Medicine, Radiation Oncology, Radiology, and Radiation Safety). For external resources, contact a regional poison control center (in the United States, call 1-800-222-1222 ) or REAC/TS at Oak Ridge, Tennessee (https://orise.orau.gov/reacts/; telephone: 865-576-1005 [emergency number] or 865-576-3131 [general information]).

•Deploy facility supplies, personal protective equipment, and radiation measurement and monitoring devices (table 1); obtain a background radiation reading in the emergency department. (See 'Personal protective equipment' above and 'Radiation measurement and detection devices' above.)

•If large numbers of casualties are expected, establish a triage site external to the emergency department and the hospital (eg, ambulance bay or triage tent) and set up an external assessment center that is remote to the emergency department for decontamination and care of patients with minor injuries (eg, most ambulatory patients) and for radiation survey of uninjured individuals. (See 'Facility response' above.)

•Ensure radiation safety measures that limit radiation contamination and exposure of patients, hospital personnel, hospital equipment, and the facility. (See 'Radiation safety personnel' above.)

●Initial patient stabilization – Key principles for patient stabilization and triage include (see 'Initial stabilization' above):

•Critically ill patients should be stabilized and receive lifesaving treatment in the facility without delay, including emergency resuscitation and surgery as needed. Other patients should have serious injuries addressed before decontamination.

•Unless they have undergone a radiologic survey and decontamination prior to arrival at the receiving facility, assume all patients are contaminated. These individuals require repeated radiologic surveys before and after decontamination in the receiving facility.

•In a mass-casualty event, persons who are externally contaminated and with minor or no traumatic injury should be relocated to a site remote from the emergency department for decontamination.

●Hospital-based triage – Timely triage should establish the severity of mechanical trauma, burns, and other injuries. The nature and intensity of radiation exposure should also be estimated based upon history. Health care providers should work in teams during triage and should be monitored for radiation exposure with physical dosimetry under the direction of the radiation safety officer. (See 'Hospital triage' above.)

●Categorize patients based on exposure – Once medical classification has been assigned based upon history and, when indicated, a survey for radiation contamination with documentation of findings (figure 1A-B), patients should be further categorized and treated according to the following determinations:

•Radiologically exposed and contaminated (externally or internally) – These patients require decontamination. Methods of radiologic decontamination and important modifications for children who warrant external and/or internal decontamination are provided above. (See 'Exposed and contaminated patients' above and 'Pediatric considerations' above.)

•Radiologically exposed (total or partial body exposure) without contamination – These patients pose no contamination risk to others. They require estimation of exposure and treatment according to type and severity of radiation injury. (See 'Exposed patients (no contamination)' above and 'Ongoing management' above.)

•Unexposed to radiation – Management should be based on the nature and extent of other injuries and degree of psychologic distress. (See 'Unexposed patients' above.)

All patients, including those who have insignificant or no exposure, may have significant psychosocial needs; reassurance and counseling should be offered to all individuals.

●Laboratory evaluation – For patients with suspected radiation exposure, initial laboratory studies should include (see 'Estimation of radiation exposure' above):

•Red blood cell type and screen

•Initial and serial measures of:

-Complete blood count (CBC) with differential

-Electrolytes, glucose, blood urea nitrogen and creatinine

-Liver enzymes and liver function tests, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), fractionated bilirubin, total serum protein, albumin

•Baseline prothrombin time (PT)/international normalized ratio (INR) and partial thromboplastin time (PTT)

•Baseline urinalysis

Blood studies should be drawn from an uncontaminated skin area. All samples should be labelled as radioactive before sending for analysis.

●Clinical manifestations – Radiation injury can affect the skin, hematopoietic system, gastrointestinal (GI) tract, brain, and other organ systems, but initial symptoms are nonspecific (table 10). (See "Clinical manifestations, evaluation, and diagnosis of acute radiation exposure".)

●Ongoing management – A summary of ongoing management is provided above. A treatment algorithm for the diagnosis and treatment of acute radiation syndrome is available through the Radiation Emergency Medical Management website; treatment guidelines are available through the Radiation Injury Treatment Network. (See 'Ongoing management' above.)

These patients typically require multidisciplinary care and should be managed by or in consultation with experts in management of radiologic injury. Disposition to an outpatient, inpatient, or specialized center (eg, burn unit, transplantation unit) setting is informed by the predominant clinical manifestations and severity of injuries (algorithm 2). (See 'Multidisciplinary management' above.)

●Hematopoietic toxicity – Management of hematopoietic toxicity is stratified according to the degree of myelosuppression as determined by CBC with differential and signs of bleeding (table 3). (See 'Hematopoietic syndrome' above.)

•Stratification of care – Specific treatments and preferred site of care are stratified according to the severity of hematopoietic injury, age, medical fitness, other radiation-induced organ toxicity, the presence of combined injury (burns or trauma), and institutional resources, as detailed above. (See 'Stratification of care' above.)

•Transfusions – Transfusion support for anemia and/or thrombocytopenia should utilize leukoreduced and irradiated or pathogen-reduced cellular blood products, whenever possible. (See 'Supportive care for hematopoietic ARS' above.)

•Cytokine support (see 'Supportive care for hematopoietic ARS' above):

-In a patient with grade ≥3 hematologic toxicity or ≥2 Gy suspected or confirmed radiation exposure, we recommend administration of a myeloid cytokine (eg, granulocyte colony-stimulating factor [G-CSF], granulocyte-macrophage colony-stimulating factor [GM-CSF]) (Grade 1C).

-In a patient with grade ≥3 hematologic toxicity or ≥2 Gy exposure (as above), we suggest adding romiplostim to a myeloid cytokine (Grade 2C).

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Joseph Y Allen, MD, who contributed to earlier versions of this topic review.