Acute appendicitis in children: Management

INTRODUCTION — This topic will review the management of appendicitis in children. The evaluation, diagnosis, and diagnostic imaging of acute appendicitis in children and management of appendicitis in adults are discussed separately:

●(See "Acute appendicitis in children: Clinical manifestations and diagnosis".)

●(See "Acute appendicitis in children: Diagnostic imaging".)

●(See "Management of acute appendicitis in adults".)

TERMINOLOGY — Acute appendicitis is classified as follows [1]:

●Uncomplicated – Uncomplicated appendicitis refers to an appendix that is inflamed but has an intact wall.

●Complicated – Complicated appendicitis refers to an appendix that is gangrenous or perforated with bacterial peritonitis.

During evaluation, clinical findings and diagnostic imaging may differentiate between uncomplicated and complicated appendicitis. However, the distinction may not be possible prior to surgery. For this reason, the modifiers "early" and "advanced" are sometimes used preoperatively:

●Early appendicitis – Patients with "early" or uncomplicated appendicitis have a recent onset (one to two days) of abdominal pain that, over time, has migrated from the periumbilical region to the right lower quadrant with one or more of the following (see "Acute appendicitis in children: Clinical manifestations and diagnosis", section on 'Clinical suspicion'):

•Low-grade fever, vomiting, and anorexia associated with right lower quadrant tenderness on physical examination.

•Elevation of white blood cell count, absolute neutrophil count, and/or C-reactive protein.

•Some patients with early appendicitis may have equivocal findings of appendicitis by history and physical examination but have diagnostic imaging that confirms the diagnosis. (See "Acute appendicitis in children: Diagnostic imaging", section on 'Imaging approach'.)

●Advanced appendicitis – Patients with "advanced" or complicated appendicitis have significant peritonitis indicated by rebound, guarding, or rigid abdomen; a palpable mass upon examination suggesting a phlegmon or abscess; and/or evidence of perforation or abdominal abscess on diagnostic imaging (image 1) [2,3]. However, in some patients, perforation is only discovered intraoperatively.

APPROACH — Most children with appendicitis warrant appendectomy. A minority of children with uncomplicated appendicitis and findings suggesting a low likelihood of perforation may be candidates for nonoperative management. (See 'Uncomplicated appendicitis' below and 'Nonoperative management' below.)

Similarly, appendectomy is recommended for all children with complicated appendicitis and ill-appearing children with perforation and a phlegmon or abscess. Selected well-appearing children with an appendiceal phlegmon or abscess without an appendicolith may undergo delayed appendectomy after a course of intravenous antibiotics with or without percutaneous abscess drainage. (See 'Complicated appendicitis' below and 'Abscess or phlegmon' below.)

Whenever available, a pediatric surgeon or surgeon with pediatric expertise should care for children who are ≤5 years old or have medical conditions that increase operative risk [4].

UNCOMPLICATED APPENDICITIS — Uncomplicated appendicitis is defined as appendicitis without evidence of gangrene or perforation. (See 'Terminology' above.)

Appendectomy — Most children with uncomplicated appendicitis warrant prompt surgery. For children with uncomplicated appendicitis who have any one of the following risk factors for perforation, we recommend appendectomy:

●Abdominal pain for ≥48 hours

●White blood cell (WBC) count >18,000/microL

●Elevated C-reactive protein

●Appendicolith present on imaging

●Appendix diameter >1.1 cm on imaging

●Preoperative concern for rupture based upon clinical findings

For children with appendicitis and none of these risk factors, we suggest against nonoperative management (NOM). NOM does remain an option for selected low-risk patients, depending upon caregiver preference after shared decision-making with the managing pediatric surgeon as described in the algorithm (algorithm 1). A minority of children with early appendicitis meet criteria for NOM. (See 'Nonoperative management' below.)

The rationale for timely removal of an inflamed appendix is that it prevents progression to rupture with peritonitis in some children and is curative [5-7]. Perforated appendicitis is associated with a significantly increased risk of morbidity (eg, surgical site infections, paralytic ileus) and mortality. Timely appendectomy substantially reduces these risks and has been the standard approach since the 1890s [8]. (See 'Post-appendectomy complications' below.)

Appendectomy also permits direct pathologic examination of the appendix and diagnosis of rare but important coexisting conditions (such as a carcinoid tumor) or alternative diagnoses (such as terminal ileitis or ovarian torsion) that change subsequent management [9].

Preoperative care — Key aspects of preoperative care for children with early appendicitis include fluid therapy, analgesia, and antibiotic prophylaxis:

●Fluid therapy – Intravenous (IV) hydration is given according to hydration status:

•Signs of dehydration – For patients with signs of dehydration, replete with balanced crystalloid solutions (eg, normal saline or lactated Ringer's) as described separately. (See "Treatment of hypovolemia (dehydration) in children in resource-abundant settings".)

Ensure rehydration based upon clinical response and no major electrolyte abnormalities before surgery.

•No signs of dehydration – Patients without dehydration may receive lactated Ringer's with additional potassium as needed infused at a rate of 1 to 1.5 times maintenance. (See "Treatment of hypovolemia (dehydration) in children in resource-abundant settings".)

●Analgesia – Pain management should be guided by the patient's self-assessment of pain severity whenever possible. For patients with mild pain, acetaminophen or, if the surgeon agrees, ketorolac often provides good analgesia. For patients with moderate to severe pain, preoperative administration of IV opioids (eg, morphine) is typically the best choice. (See "Pain in children: Approach to pain assessment and overview of management principles" and "Approach to the management of acute perioperative pain in infants and children".)

●Antibiotic treatment – We recommend administration of broad-spectrum antibiotics to cover colonic flora as soon as the diagnosis of appendicitis is established [10,11]. If more than 1-2 hours have passed since the last dose of antibiotics most surgeons give an additional dose 30 to 60 minutes before the incision. However, a recent retrospective review suggests that redosing of prophylactic antibiotics prior to incision does not appear to be necessary in most patients unless cefoxitin is used [12].

Acceptable antibiotic choices include:

•Cefoxitin

•Ceftriaxone and metronidazole

•Cefotetan

•Ciprofloxacin and metronidazole in patients allergic to penicillins and cephalosporins

•Piperacillin and tazobactam

Patients with simple appendicitis do not require further doses of antibiotics after appendectomy. By contrast, antibiotics should be continued postoperatively in children with complicated (gangrenous or perforated) appendicitis. (See 'Postoperative care' below.)

•Rationale and efficacy for prophylactic antibiotics – The effectiveness of prophylactic antibiotics in patients with early appendicitis is supported by a meta-analysis of four placebo-controlled trials that included 1090 children with appendicitis [11]. Among children with early appendicitis (n = 648), prophylactic antibiotics reduced the risk of intra-abdominal abscesses (0.2 versus 1.2 percent, odds ratio [OR] 0.14, 95% CI 0.02-0.98). While these trials did not detect a significant reduction in postoperative wound infections, numerous other randomized trials (most involving adult patients) have demonstrated that prophylactic antibiotics reduce surgical site infections. These data are discussed separately. (See "Management of acute appendicitis in adults", section on 'Prophylactic antibiotics' and "Antimicrobial prophylaxis for prevention of surgical site infection in adults".)

Whether additional doses of antibiotics are more effective than a single preoperative dose was not addressed by this meta-analysis. However, a systematic review by the American Pediatric Surgical Association concluded that evidence is lacking to support postoperative antibiotics in children with nonperforated appendicitis. Most experts agree that additional doses of antibiotics in these patients are unnecessary [13].

The inclusion of piperacillin and tazobactam for prophylaxis of uncomplicated appendicitis in children differs from joint guidelines for prophylaxis for simple appendectomy proposed by the Infectious Diseases Society of America, the Surgical Infection Society, The American Society of Health-System Pharmacists, and the Society for Healthcare Epidemiology of America [14] but is consistent with guidelines proposed by the American Pediatric Surgical Association [13]. The use of piperacillin and tazobactam for such patients is based upon the frequent difficulty in identifying whether the appendix is perforated in children based on imaging prior to operation. However, in an observational study of almost 18,000 children with uncomplicated appendicitis, of whom one-third received extended-spectrum antibiotics (primarily piperacillin and tazobactam), treatment failure, defined as readmission within 30 days related to a complication of appendicitis, occurred in approximately 1 percent of all patients and was not reduced in the patients receiving extended-spectrum antibiotics (adjusted odds ratio [aOR] 1.32, 95% CI 0.9-2.0) [15].

Timing of operation — In the past, appendicitis has been considered a surgical emergency that requires prompt appendectomy to avoid perforation and other complications. However, evidence from observational studies suggests that adverse outcomes (eg, perforation, complications, or operating time) are not increased for children who receive timely administration of antibiotics and undergo appendectomy less than 24 hours after diagnosis [16-19]. For example, in a multicenter, prospective, observational study of almost 1000 children 3 to 18 years of age with appendicitis, duration of time ≤24 hours between emergency department evaluation and operation was not associated with a significant increase in appendiceal perforation on adjusted analysis, including children without perforation on computed tomography (CT) of the abdomen during initial evaluation [17]. A retrospective observational study of over 2400 children undergoing appendectomy at 23 children's hospitals also found no association between time to appendectomy ≤24 hours and complicated appendicitis or postoperative complications [18].

On the other hand, operative delay beyond 48 hours after admission has been associated with increased risk for surgical site infections and 30-day complications [16]. In addition, a retrospective study of over 850 children with imaging demonstrating nonperforated appendicitis at diagnosis found an increased risk of perforation associated with increasing time from emergency department diagnosis to surgery [20]. However, the duration of symptoms was not considered in this study, and other studies have found that limiting the total duration of symptoms prior to appendectomy rather than the time from diagnosis to surgery appears to be of greatest importance in preventing perforation and other adverse outcomes [21,22]. As an example, in a prospective observational study that evaluated 230 children who underwent appendectomy, patients with symptoms for ≥48 hours had a significantly higher rate of perforation when compared with patients with symptoms ≤48 hours (46 versus 12 to 18 percent) [21]. When evaluated according to time from diagnosis, the perforation rate, length of stay, and operating time were not significantly different.

Laparoscopic or open approach — For children undergoing appendectomy for uncomplicated appendicitis, we recommend a laparoscopic approach rather than open appendectomy.

Evidence supporting laparoscopic over open appendectomy comes from randomized trials and observational studies [23-25]. In a meta-analysis of ten randomized trials comparing laparoscopic versus open appendectomy in 1245 children with acute appendicitis, laparoscopy reduced hospital length of stay (mean difference 19 hours) and lowered the risk of wound infection (2 versus 8 percent; OR 0.25, 95% CI 0.15-0.42) [24]. Rates of intra-abdominal abscesses were also lower in the laparoscopy group, but the difference was not statistically significant (1.4 versus 2.6 percent; OR 0.54, 95% CI 0.24-1.22). In the single trial that reported time to return to normal activities, laparoscopy resulted in earlier resumption of normal activities (mean difference 0.5 day sooner) [24,26]. The mean difference in operative time in these trials was 7 to 11 minutes longer for laparoscopy, which is of marginal clinical significance.

Intraoperative considerations — Important intraoperative considerations arise based upon the appearance of the appendix:

●Abnormal appendix with no visible gangrene or perforation – Recommended techniques include [1]:

•If a segment of omentum is firmly attached to the appendix, divide it a few centimeters away and remove it with the appendix.

•Ligate the base of the appendix close to the cecum. There is no proven benefit to inversion of the stump.

•Aspirate all purulent fluid.

•Close all incisions and trocar sites that are larger than 5 mm primarily.

●Perforated appendix – In some patients thought to have early appendicitis based upon preoperative clinical findings, a perforated appendix will be encountered. Intraoperative considerations for patients with complicated (advanced) appendicitis are discussed separately. (See 'Intraoperative considerations' below.)

●Normal appendix – When an apparently normal appendix is found, it should be removed. Removal of an appendix that appears grossly normal is generally recommended because microscopic inflammation may be noted on pathologic examination [27]. Removal of the appendix will also significantly diminish concern for the diagnosis of appendicitis if the patient develops another episode of abdominal pain, although stump appendicitis remains possible.

Evidence for other possible causes of abdominal pain, including Meckel's diverticulitis, terminal ileitis, mesenteric adenitis, omental torsion, renal mass or obstruction, cholecystitis, or tubal or ovarian pathology should be sought if the appendix appears to be normal.

●Carcinoid tumor – Rarely, a carcinoid tumor will be seen or palpated in the appendix at the time of appendectomy and is typically discovered during pathologic examination [28]. Further management depends upon the size of the tumor and pathologic characteristics as discussed separately. (See "Staging, treatment, and post-treatment surveillance of non-metastatic, well-differentiated gastrointestinal tract neuroendocrine (carcinoid) tumors", section on 'Appendix'.)

Postoperative care — The principal management issues after appendectomy in children with acute uncomplicated appendicitis include adequate pain control and resumption of oral intake:

●Analgesia – Evidence is lacking to guide optimal post-appendectomy pain management, and practice varies widely [29]. Close attention to pain assessment and resolution of pain is essential, regardless of the regimen chosen. (See "Pain in children: Approach to pain assessment and overview of management principles", section on 'Severity assessment'.)

In our experience, adequate pain control is frequently achieved by wound blocks at the time of surgery and a postoperative regimen of scheduled parenteral or oral acetaminophen and nonsteroidal antiinflammatory drugs (NSAIDs). Opioid medication is rarely needed for rescue therapy. This opioid-free approach is now widely used in patients undergoing minimally invasive surgery with same-day discharge and avoids side effects such as drowsiness and constipation.

In an observational study of over 260 children post appendectomy, a protocol consisting of cold therapy to incision sites in the post-anesthesia care unit, prompt pain assessment upon arrival to the acute care ward, and a pain regimen alternating acetaminophen and ibuprofen with oxycodone for rescue therapy reduced post-operative oral opioid use, number of prescribed opioid doses at discharge, and return visits for pain or constipation compared with historical controls [30]. Recently, several institutions have launched quality improvement interventions that promote opioid stewardship and enhanced recovery after surgery (ERAS) principles for pediatric appendectomy, as well as other simple outpatient procedures. In a single center study, there was high adherence to an over-the-counter pain medication regimen after appendectomy with high rates of parental satisfaction reported [31].

In the past, use of NSAIDs was discouraged because of the theoretical risk of bleeding. However, in studies of their use after other operations where hemorrhage is more likely to occur (eg, tonsillectomy), NSAIDs have not been associated with increased bleeding [32]. In one observational study of 186 children undergoing appendectomy for early appendicitis using a single-incisional laparoscopic technique, pain control with oral NSAIDs was adequate for most patients [33].

●Oral intake and diet – For most patients, oral fluids can be introduced as soon as the child is awake. Diet may be advanced to solid food as tolerated. If admitted, most children with uncomplicated appendicitis can go home within 24 to 48 hours. Some centers now discharge these patients on the day of surgery once adequate pain control and ability to tolerate liquids and solids are confirmed.

●Antibiotics – Uncomplicated appendicitis does not require post-operative antibiotics. Postoperative antibiotics for gangrenous or perforated appendicitis is discussed separately. (See 'Postoperative care' below.)

Same-day discharge — Evidence suggests that selected children with early appendicitis may be discharged on the same day of surgery with high caregiver satisfaction and without an increase in complications, urgent revisits, or readmissions when compared with overnight hospitalization [33-35].

Nonoperative management — Appendectomy for early appendicitis remains the treatment of choice for most children diagnosed with appendicitis. When performed by a pediatric surgeon or surgeon with pediatric expertise, NOM may be an option for selected children who can verbally describe their symptoms, have a reliable and reproducible abdominal examination, meet strict criteria, and after shared decision-making between the managing pediatric surgeon and the parent/primary caregiver [36-39].

●Patient selection and antibiotic regimens – Patient selection for NOM, advantages and disadvantages of NOM, and sample antibiotic regimens are provided in the algorithm (algorithm 1). (See 'Nonoperative management' above.)

Only a minority of children diagnosed with appendicitis are potential candidates for NOM. For example, in one large, nonrandomized, multicenter trial, approximately 20 percent of children presenting with appendicitis met criteria [37]. Among children who initially receive NOM, appendectomy still occurs in up to 18 percent within 14 days of presentation and in up to 33 percent by one year [37,40-42]. Given the significant risk of failure, NOM may be most appropriate in children who are at low risk for perforation and who have comorbidities that raise the risk of appendectomy or general anesthesia.

Antibiotic protocols vary widely but typically include one to two days of inpatient broad spectrum IV therapy (eg, piperacillin-tazobactam, ceftriaxone and metronidazole, or ciprofloxacin and metronidazole) until resolution of symptoms and normalization of WBC count occur followed by oral antibiotics (eg, amoxicillin-clavulanic acid or ciprofloxacin and metronidazole) as an outpatient [43].

●Efficacy – Prospective, nonrandomized, and randomized trials in children report early and one-year success rates for NOM (ie, resolution of symptoms, no surgery during initial hospitalization, and no recurrent appendicitis) of 85 to 91 percent and 67 to 87 percent, respectively [37,40-42], with the highest success rates achieved when strict criteria for NOM are used [42]. In the largest of these studies, a prospective, multicenter, nonrandomized controlled trial of over 1000 children with appendicitis (370 who received NOM per caregiver preference), complication-free treatment success was 85 percent during early NOM at initial admission and 67 percent at one-year follow-up [37]. Compared with surgery, children undergoing NOM had fewer days of disability at one year (7 versus 11 days) but higher rates of emergency department visits (25 versus 7 percent) and readmissions (23 versus 3 percent). The negative appendectomy rate was 7.5 percent in the surgical group and 1.4 percent in children receiving NOM who underwent surgery after initial hospitalization. However, the generalizability of this study is limited by high loss to follow-up in both treatment groups.

Among children who undergo NOM, a significant portion may experience early failure (need for appendectomy within 14 days of initial presentation). Among patients who fail NOM, the likelihood of perforation at operation may be increased. For example, in a large, retrospective study of >7400 children reported to a national hospital database and undergoing NOM, 18 percent had early failure and 2 percent had late failure (median time 4.2 years) [40]. At the time of failure, 46 percent had a diagnosis of perforated appendicitis, which was higher than the proportion of children undergoing appendectomy at the index visit (38 percent). Patients undergoing NOM also had higher rates of emergency department visits and hospitalizations. Because this study relied on diagnosis codes from an administrative database, these rates may not be accurate. The higher rates of revisits and hospital admissions in children undergoing NOM are consistent with the prospective trial discussed below. Further data from a prospective trial is necessary to confirm the risk of perforated appendicitis in children who fail NOM.

With respect to caregiver values and preferences, one online survey of over 1700 parents found that 85 percent of caregivers would prefer surgery over nonoperative management if their child had appendicitis, primarily due to concerns about the potential for perforation and death [38]. However, in another study, when presented with education and treatment options, especially the low risk of perforation and mortality if nonoperative management is used, only about 60 percent of caregivers still preferred surgery [39].

The use of NOM in children may be increasing. In a retrospective study of a United States hospital administrative database of >73,500 children treated for nonperforated appendicitis over nine years, 14 percent were managed nonoperatively with an increase from 3 percent in the first quarter of 2011 to 33 percent in the first quarter of 2020 [40]. In a separate study of over 2000 children treated for appendicitis in the United Kingdom and Ireland during the early period of the COVID-19 pandemic, nonoperative treatment was performed in 28 percent of children during the pandemic compared with none in the pre-pandemic cohort (over 600 children) [44]. However, since emergency health restrictions related to the COVID-19 pandemic have eased, experience in our institutions is that NOM has returned to pre-pandemic levels.

COMPLICATED APPENDICITIS — Complicated appendicitis means that the appendix is gangrenous or perforated. Management of complicated appendicitis depends upon whether or not the patient has an abscess or phlegmon and their clinical status as described below. (See 'Terminology' above.)

No abscess or phlegmon

Appendectomy — For children with complicated appendicitis and no abscess or phlegmon, we recommend early appendectomy rather than interval appendectomy.

This recommendation is based upon more rapid recovery and fewer complications when these patients undergo appendectomy at initial presentation [45-47]. For example, in a patient-level metanalysis of 2 trials (171 children), children with complicated appendicitis and no abscess who had early appendectomy had fewer adverse effects than those who received empiric antibiotics followed by interval appendectomy (OR 0.28, 95% CI 0.10 to 0.77) [46]. In a separate trial not included in this metaanalysis, adverse effects were also lower in patients with complicated appendicitis who had early appendectomy and resulted in lower hospital charges and costs [48].

Preoperative care and surgical approach — The preoperative care and surgical approach for children with complicated appendicitis and no abscess or phlegmon is the same as for uncomplicated appendicitis. (See 'Preoperative care' above.)

For these patients, we recommend a laparoscopic approach rather than open appendectomy. Evidence supporting laparoscopic appendectomy in children with complicated appendicitis comes from randomized trials and observational studies [25,49-51]. For example, in a systematic review and meta-analysis of 4 randomized trials and 36 observational studies, laparoscopic appendectomy (over 2800 children) was associated with shorter hospital length of stay and lower risk of any postoperative complication, including lower risk of surgical site infection and lower risk of bowel obstruction compared with open appendectomy (over 3300 children) [50].

Intraoperative considerations — Variation exists among pediatric surgeons regarding the intraoperative management of complicated appendicitis in children [52]. We, along with most others, follow these general principles [1]:

●A search should be made for an appendicolith in the pelvis or periappendiceal area when the appendix is grossly perforated, especially if one was noted on the preoperative imaging.

●We do not routinely culture the stump, free pus, or peritoneal fluid because the results almost never alter treatment.

●The base of the appendix should be ligated close to the cecum.

●A drain should be inserted if there is a well-formed abscess cavity or if the stump closure is tenuous.

●Aspiration of obvious purulent material is recommended for children with perforated appendicitis, but data are conflicting as to whether or not the addition of intraoperative irrigation is effective in reducing postoperative abscess formation and/or wound infection [53-56].

●Wounds should be irrigated generously and closed primarily.

Postoperative care — Postoperative care of complicated appendicitis without phlegmon or abscess focuses on empiric antibiotic therapy, pain control, and nutrition:

●Empiric antibiotics – Children with perforated or gangrenous appendicitis require intravenous (IV) antibiotic therapy postoperatively designed to cover expected colonic flora after appendectomy. For most children with complicated appendicitis, we suggest piperacillin/tazobactam as recommended by the American Pediatric Surgical Association guidelines [13]. However, some experts use ceftriaxone and metronidazole instead of piperacillin/tazobactam. For patients with penicillin allergy, we use ciprofloxacin and metronidazole.

•Duration of antibiotics and use of oral antibiotics – Our approach is to continue IV antibiotics in children with complicated appendicitis until they meet the following criteria:

-Afebrile

-Pain well controlled on oral analgesics

-Tolerating a regular diet

-Ambulating

-Benign abdominal examination (no mass or tenderness)

We discharge patients with complicated appendicitis when they meet our discharge criteria even if they have been treated for fewer than five days. Children who are still febrile, have a white blood cell (WBC) count ≥12,000/mm³, and/or are unable to tolerate a regular diet five to seven days after surgery warrant diagnostic imaging studies to assess for an abdominal or pelvic abscess [57]. (See 'Post-appendectomy complications' below.)

Although a minimum of five days of IV antibiotics is recommended by the American Pediatric Surgical Association (APSA) guidelines [13,58], several studies published after these guidelines have reported good outcomes with durations of IV antibiotics <5 days in selected patients [59,60]. For example, in an observational study of 510 children with complicated appendicitis, length of stay and rates of abscess formation or readmission were not significantly different for patients who met the above clinical criteria but did not receive oral antibiotics at discharge [60].

•Efficacy – The efficacy of antibiotic therapy in the treatment of gangrenous or perforated appendicitis was established in placebo-controlled trials conducted in the 1970s to 1990s demonstrating that IV antibiotic therapy reduces wound infection and intra-abdominal abscess formation [11]. While most of these trials involved adult patients, it is reasonable to expect that the same benefits apply to pediatric patients.

Evidence is inconsistent regarding the optimal regimen and growing resistance of organisms isolated from patients with complicated appendicitis has been observed [61]. Thus, some experts suggest a simple antibiotic regimen such as cefuroxime and metronidazole or ampicillin-sulbactam as the initial preoperative antibiotic with administration of an extended spectrum regimen such as piperacillin/tazobactam if intraoperative appendicitis severity is high [62].

In a small randomized trial of 162 children with perforated appendicitis, individuals assigned to piperacillin/tazobactam compared with ceftriaxone and metronidazole had lower rates of intraabdominal abscess, postoperative imaging, and fewer emergency room visits [63]. However, in a separate observational study of over 7000 children with complicated appendicitis, treatment failure, defined as readmission within 30 days related to a complication of appendicitis, occurred in approximately 6 percent of all patients with complicated appendicitis and was increased in patients who received extended spectrum antibiotics [15]. Other cohort studies also suggest similar outcomes for patients who receive ceftriaxone and metronidazole compared with extended spectrum coverage regimens such as piperacillin/tazobactam, ertapenem alone, or ertapenem combined with cefoxitin [64,65].

●Pain control – Postoperative pain following laparoscopic appendectomy is typically well-controlled in most patients with scheduled acetaminophen and supplemental ketorolac, although some patients may require rescue doses of opioids on an as needed basis. Oral analgesics such as acetaminophen or ibuprofen, with rescue hydrocodone or oxycodone can be substituted once the child is drinking well.(See "Pain in children: Approach to pain assessment and overview of management principles", section on 'Opioids' and "Pain in children: Approach to pain assessment and overview of management principles", section on 'Nonopioid analgesics'.)

●Nutrition – Parenteral nutrition support is usually not needed in children with complicated appendicitis. However, it is indicated in previously healthy children who are unable to eat after one week [66]. Those who are already malnourished should begin parenteral nutrition within 48 to 72 hours following surgery. (See "Parenteral nutrition in infants and children".)

●Intestinal dysfunction – Some patients with complicated appendicitis may experience paralytic ileus or, less commonly, a mechanical intestinal obstruction from fibrinous adhesions. Nasogastric drainage should be instituted for patients with persistent vomiting or abdominal distension.

Abscess or phlegmon — The approach to patients with an appendiceal phlegmon or abscess varies depending upon their clinical appearance.

●Ill-appearing – Ill-appearing patients with evidence of an appendiceal phlegmon or abscess require empiric antibiotics. For these patients, we recommend prompt appendectomy. (See 'Appendectomy' above.)

●Well-appearing – Well-appearing children with a delayed presentation (more than five to seven days from the onset of the illness) who have a well-localized abscess or inflammatory mass (phlegmon) should receive empiric antibiotics as for children with complicated appendicitis and no phlegmon or abscess. We suggest piperacillin/tazobactam as recommended by the American Pediatric Surgical Association guidelines [13]. However, some experts use ceftriaxone and metronidazole instead of piperacillin/tazobactam. For patients with penicillin allergy, we use ciprofloxacin and metronidazole.

Because of the high risk of morbidity including postoperative infection, intestinal fistula, small bowel obstruction, and recurrence, immediate appendectomy is typically avoided in well-appearing children [3]. Instead, the patient receives nonoperative management (NOM) with antibiotics until signs and symptoms resolve. These children should also undergo imaging upon admission to identify candidates for image-guided percutaneous drainage. Significant abscesses (>3 to 4 cm in diameter) are typically drained under image guidance by an interventional radiologist. Even multiple intra-abdominal abscesses may be managed in this fashion [67].

Children undergoing initial nonoperative management should have steady improvement in abdominal pain, fever, appetite, and intestinal function. After resolution of the initial infection, for most well-appearing children, we suggest interval appendectomy at 10 to 12 weeks [68]. Interval appendectomy is most likely to benefit children with an appendicolith because they may have an increased risk of recurrence [69]. In well-appearing children without an appendicolith, the surgeon should involve parents/primary caregivers in shared decision-making. For children who undergo nonoperative management, the risk of recurrence ranges from 7 to 23 percent in observational studies and small pediatric trials [3,70,71]. In addition, the potential for delayed diagnosis of underlying pathology (eg, Crohn disease or carcinoid tumor) in children who do not have interval appendectomy is approximately 1 to 2 percent [3,68,71].

By contrast, the risk of serious postoperative complications in children undergoing interval appendectomy such as wound infection, abscess formation, bowel obstruction, or prolonged ileus is approximately 3 to 6 percent [70,72].

DISCHARGE CRITERIA (ALL PATIENTS) — The timing of discharge is based on the clinical condition of the patient. Children, regardless of how their appendicitis was treated, who are afebrile, tolerating a regular diet, and free of pain or well controlled on non-narcotic analgesics are ready for discharge. This typically requires a longer stay for patients with complicated appendicitis, but the criteria are similar.

Patients who meet these criteria appear to be at lower risk for post-appendectomy complications. For example, in a case-control study comparing children with perforated appendicitis who developed intra-abdominal abscesses with those who did not, none of the patients who were afebrile and eating on the third postoperative day developed intra-abdominal abscesses [73].

POST-APPENDECTOMY COMPLICATIONS — Children with uncomplicated appendicitis have a risk of wound infection or abscess of approximately 1 to 5 percent [23,24].

Up to 55 percent of children with complicated appendicitis may experience a complication such as infection, bowel obstruction, or unplanned hospital re-admission [74]. The risk of abscess is higher in children with body mass index >95^th percentile [75,76].

Early

●Infection – Infections that occur after appendectomy include wound infection (rate 2 to 9 percent) and intra-abdominal/pelvic abscesses (rate approximately 5 percent) [77-80]. Infectious complications are more likely after operation for complicated appendicitis.

The typical symptoms of postoperative infection are fever, anorexia, inability to tolerate a normal diet, and pain in and around the incision site(s) or in the abdomen and pelvis. Patients with these symptoms should be seen promptly, preferably in consultation with the surgeon or surgical service who performed the appendectomy. If there is no obvious wound infection on physical examination, an abdominal and pelvic ultrasound should be obtained. Once the presence of an abscess is identified, a CT scan of the abdomen and pelvis is often indicated to precisely define the problem (because there may be more than one purulent collection) and to serve as a guide to the feasibility of image-guided drainage.

Wound abscesses are treated by opening the wound to permit drainage and healing by secondary intention.

Most abdominal and pelvic abscesses can be treated by percutaneous drainage under ultrasound or CT guidance. Pelvic abscesses, which point into the rectum, may be treated by transrectal drainage.

●Intestinal dysfunction – Intestinal dysfunction is the second most common complication of appendicitis [1]. Causes include paralytic ileus, constipation, mechanical obstruction, and rarely, intussusception. In the first few days after appendectomy, intestinal dysfunction is usually caused by paralytic ileus from peritonitis which usually resolves with gut rest including nasogastric suction and intravenous (IV) fluids. Parenteral nutrition support is indicated if the patient is unable to eat for more than five to seven days [66]. (See 'Postoperative care' above.)

Constipation typically occurs later than paralytic ileus, often after discharge. Multiple factors may contribute, including reduced appetite, changes in diet, reduced physical activity, and narcotic drugs. A presumptive diagnosis of constipation can be established by phone conversation, and treatment can be initiated on an outpatient basis, but if intake is poor, especially if accompanied by vomiting, the child should be seen promptly for a thorough clinical assessment.

Plain abdominal radiographs are very useful in distinguishing paralytic ileus from constipation. In paralytic ileus, radiographs show diffuse bowel dilation. With constipation, excess stool and gas can be seen in the colon with little to no small bowel dilation.

Late

●Small bowel obstruction – Mechanical small bowel obstruction from postoperative and postinflammatory adhesions occurs in less than 1 percent of children [81]. This is rare in the early post-operative period; most patients with a complete bowel obstruction present several weeks after appendectomy.

●Stump appendicitis – Stump appendicitis refers to the inflammation of residual appendiceal tissue months to years after an appendectomy [82-84]. This rare condition has been attributed to incomplete appendectomy that leaves an excessively long stump after open or laparoscopic surgery. Clinical findings are similar to acute appendicitis, and the diagnosis should be considered in any patient with right lower quadrant pain despite the prior history of appendectomy.

A retrospective observational report found three patients out of 2185 developed stump appendicitis following primary appendectomy [84]. Ultrasound or CT of the abdomen with contrast assists in establishing the diagnosis. A review of 36 case reports found that the median time to presentation is one year after initial operation with a range of four months to 50 years [83]. Perforation occurred in 70 percent of patients.

●Mortality – Because of advances in diagnostic imaging and sepsis care, mortality caused by appendicitis is low (<0.1 percent) [85].

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: Appendicitis in children".)

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Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Appendicitis in adults (The Basics)" and "Patient education: Appendicitis in children (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Uncomplicated appendicitis (inflamed appendix with an intact wall) – Most children with uncomplicated appendicitis warrant prompt surgery:

•The management of uncomplicated appendicitis in children is provided in the algorithm (algorithm 1). For children with uncomplicated appendicitis and any one of the following risk factors for perforation, we recommend appendectomy within 24 hours of diagnosis (Grade 1B) (see 'Appendectomy' above and 'Timing of operation' above):

-Abdominal pain for ≥48 hours

-White blood cell (WBC) count >18,000/microL

-Elevated C-reactive protein

-Appendicolith present on imaging

-Appendix diameter >1.1 cm on imaging

-Preoperative concern for rupture based upon clinical findings

For children with appendicitis and none of these risk factors, we suggest appendectomy (Grade 2C). Nonoperative management (NOM) remains an option for selected low-risk patients depending upon caregiver preference after shared decision-making between the parent/primary caregiver and the managing pediatric surgeon. NOM may be most appropriate for children who are at low risk for perforation and who have comorbidities that raise the risk of appendectomy or general anesthesia. (See 'Nonoperative management' above.)

•Preoperative management includes intravenous (IV) rehydration, correction of electrolyte abnormalities, and timely administration of prophylactic antibiotics. (See 'Preoperative care' above.)

•For children with uncomplicated appendicitis, we recommend a dose of prophylactic broad-spectrum antibiotics prior to surgery (Grade 1B). For most patients, we suggest cefoxitin, piperacillin/tazobactam, or ceftriaxone plus metronidazole rather than other regimens (Grade 2C). Antibiotics are given as soon as the diagnosis is established and at least 30 to 60 minutes before surgery. (See 'Preoperative care' above.)

•For children with uncomplicated appendicitis who are undergoing appendectomy, we recommend a laparoscopic rather than open procedure (Grade 1B). (See 'Laparoscopic or open approach' above.)

•At operation, an apparently normal appendix requires removal. A careful search for other causes of abdominal pain including tubo-ovarian pathology in females should be performed. (See 'Intraoperative considerations' above.)

•Following surgery, oral fluids may be offered as soon as the child is awake. Analgesia may be given orally as well. Most children can go home within 24 hours. (See 'Postoperative care' above.)

●Complicated appendicitis (gangrenous or perforated appendix) – Management of complicated appendicitis depends on whether the patient has an abscess or phlegmon and their clinical status:

•No abscess or phlegmon – For children with complicated appendicitis who do not have an appendiceal phlegmon or abscess, we recommend urgent appendectomy rather than delayed appendectomy (Grade 1B). We also recommend laparoscopic appendectomy rather than an open technique (Grade 1B). (See 'Appendectomy' above and 'Preoperative care and surgical approach' above.)

Preoperative management of children with advanced appendicitis includes replacement and maintenance fluid therapy, analgesia, and IV broad-spectrum antibiotics as for children with uncomplicated appendicitis.

Children with perforated or gangrenous appendicitis require broad-spectrum antibiotic therapy postoperatively. We suggest empiric coverage with piperacillin/tazobactam rather than other agents (Grade 2C). The optimal duration of antibiotic therapy is uncertain; usual practice is to continue treatment until the patient is afebrile and tolerating a regular diet. Children who are still febrile and/or unable to tolerate a regular diet 7 to 10 days after surgery may have an abdominal or pelvic abscess and should have diagnostic imaging studies. (See 'Postoperative care' above.)

Other postoperative management issues include pain control, nutrition, and management of intestinal dysfunction. (See 'Postoperative care' above.)

•Abscess or phlegmon – The approach to children with an appendiceal phlegmon or abscess varies depending upon their clinical appearance (see 'Abscess or phlegmon' above):

-Ill-appearing – Ill-appearing patients with an appendiceal mass or phlegmon require immediate appendectomy.

-Well-appearing – Patients who present more than five to seven days from the onset of the illness with a well-localized abscess or inflammatory mass (phlegmon) should receive empiric antibiotics as for patients with complicated abscess and no phlegmon or abscess. Immediate appendectomy is typically avoided.

For most well-appearing patients managed with initial nonoperative treatment, we suggest interval appendectomy 10 to 12 weeks after resolution of the initial episode (Grade 2C). Interval appendectomy is most likely to benefit children with an appendicolith, because they have increased risk of recurrence. In well-appearing children without an appendicolith, the surgeon should involve parents/primary caregivers in shared decision-making to weigh the risk of post-operative complications with interval appendectomy versus potential recurrence or delayed diagnosis of underlying pathology (eg, Crohn disease or carcinoid tumor) with NOM. (See 'Abscess or phlegmon' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges David E Wesson, MD, who contributed to earlier versions of this topic review.