Back pain in children and adolescents: Causes

INTRODUCTION — Most back pain in children and adolescents is nonspecific and commonly caused by benign musculoskeletal conditions (eg, Scheuermann kyphosis) and trauma (table 1A). Less common, but potentially serious, causes include infections (eg, vertebral osteomyelitis), malignant tumors (eg, Ewing sarcoma), and inflammatory arthritis (table 1B). Potentially serious causes of back pain often are associated with warning signs (table 2).

The causes of back pain in children and adolescents (table 1A-B) will be reviewed here. The epidemiology and evaluation of back pain in children are discussed separately. (See "Back pain in children and adolescents: Evaluation".)

NONSPECIFIC MUSCULOSKELETAL PAIN AND MUSCLE STRAIN — Nonspecific musculoskeletal pain and paraspinal muscle strain are the most common causes of back pain in children and adolescents, together accounting for at least 50 percent of cases, depending on the study population [1-7]. Children with nonspecific musculoskeletal pain and muscle strain do not have warning signs of potentially serious causes (table 2).

Factors that have been associated with nonspecific paraspinal back pain in children and adolescents include:

●Older age and sports participation [8-10]

●Use of an especially soft mattress (has also been associated with back stiffness in the morning) [11]

●Large breasts (see "Breast disorders in children and adolescents", section on 'Juvenile breast hypertrophy')

●Sports equipment (eg, improper bicycle seat positioning, lack of cushioned insoles for running) [12]

●Spinal morphology (eg, increased thoracic kyphosis) and range of motion [13]

●Depression, anxiety, and psychosocial distress [2,14,15] or comorbid medical disorders (eg, asthma, headache) [16]

Although heavy backpacks have been associated with back pain in some observational studies [17-21], in a systematic review of five prospective studies, backpack characteristics (eg, weight, method of carrying) were not associated with increased risk of back pain in children and adolescents [22].

Muscle strain may be related to overuse or acute injury. It is exacerbated by twisting or lifting.

Nonspecific paraspinal muscle pain and muscle strain generally resolve without sequelae, although some children and adolescents develop prolonged and occasionally disabling pain similar to chronic back pain in adults [23].

THORACIC SPINE PAIN

Scheuermann (juvenile) kyphosis — Scheuermann kyphosis is a structural deformity of the thoracic spine [24].

●Epidemiology – In case series, Scheuermann kyphosis is a common diagnosis in children and adolescents who present to specialty clinics with back pain, accounting for up to 20 percent of cases [4,25]. The estimated prevalence ranges from 4 to 8 percent [24,26]. It is more common in males than females [26]. Tall males are at increased risk for severe disease.

●Pathogenesis – The pathogenesis of Scheuermann kyphosis is uncertain. A genetic component is suggested by greater concordance in monozygotic than dizygotic twins [27]. In some cases, the wedging may reflect compression fractures associated with transient osteoporosis or increased compressive stress on the spine due to a relatively short sternum [26,28]. An association with sports or heavy lifting is controversial.

●Clinical features – Scheuermann kyphosis typically occurs in early adolescence and affects the thoracic spine. It may be associated with spondylolysis [29] and, rarely, myelopathy [30-32]. Pain generally is subacute without a clear episode of precipitating trauma, although it may be chronic or intermittent. The pain is worse with flexion, after activity, and at the end of the day; it improves with rest. Scheuermann kyphosis may improve with skeletal maturity. However, in one series, 38 of 47 patients (81 percent) exhibited progression of kyphosis at a mean of 30 years after initial nonsurgical management, at a rate averaging 0.45° per year; since only 47 of the 113 eligible patients consented for reimaging, it may be that this finding is skewed toward more severe patients [33]. Nevertheless, long-term follow-up studies typically suggest increased back pain and lower health-related quality of life in adulthood [33-35].

Patients with Scheuermann kyphosis have a rigid kyphosis with a relatively sharp angulation when the child bends over, best viewed from the side of the patient (figure 1). The curvature does not flatten with forward bending, extension, or lying supine (in contrast to the curvature of poor posture) [6,36]. There may be a compensatory increase in lumbar lordosis and tightening of the hamstrings manifest by limited passive straight leg raising and forward bending. The physical examination is neither sensitive nor specific for Scheuermann kyphosis [26].

●Imaging – Standing lateral spine radiographs are necessary for the diagnosis, which requires anterior wedging of ≥5° in at least three adjacent vertebral bodies (image 1) [24]. Degeneration of the vertebral end plates also may be seen (image 2). In patients with lumbar pain, concomitant spondylolysis should be considered [29]. (See 'Spondylolysis and spondylolisthesis' below.)

●Treatment – Scheuermann kyphosis usually can be treated with conservative management: strengthening and stretching exercises, analgesics, and avoidance of precipitants. Bracing or other orthopedic interventions, including surgical correction and fusion, may be warranted if pain is persistent or the kyphosis exceeds 60° [24,37,38].

THORACIC OR LUMBAR SPINE PAIN

Scoliosis — Scoliosis is an abnormal lateral curvature of the spine. It can be idiopathic or result from congenital spinal anomalies (eg, tethered cord, syringomyelia), muscular spasm or paralysis, infection (eg, vertebral osteomyelitis), tumors (eg, osteoid osteoma), or other causes. Scoliosis is a common diagnosis in children and adolescents who present to specialty clinics with back pain, accounting for 27 percent of cases in one series [25].

Although patients with adolescent idiopathic scoliosis may complain of back pain [39,40], back pain should not be attributed to scoliosis without excluding other causes of back pain. The clinical features, evaluation, diagnosis, and treatment of adolescent idiopathic scoliosis are discussed separately. (See "Adolescent idiopathic scoliosis: Clinical features, evaluation, and diagnosis" and "Adolescent idiopathic scoliosis: Management and prognosis".)

Osteoid osteoma — Osteoid osteoma is a benign bone-forming tumor and the most common tumor that presents with back pain in children. It generally occurs in the second decade of life and is more common in males than females.

Osteoid osteoma is classically characterized by nocturnal pain that is promptly relieved with nonsteroidal anti-inflammatory drugs (NSAIDs) [41]. However, pain may not be present early in the course, and in some patients pain is not relieved with NSAIDS. Ten to 20 percent of osteoid osteomas localize to the spine [42,43]. Osteoid osteoma of the spine may be associated with scoliosis secondary to bony deformity or muscle spasm.

Osteoid osteoma is diagnosed with radiographs, computed tomography, and/or magnetic resonance imaging (MRI) that demonstrate dense sclerotic bone surrounding a radiolucent osteoid nidus [41,44]. However, lesions in the spine may not be recognized on radiographs and MRI may demonstrate spinal cord edema and soft tissue inflammation, findings more suggestive of other tumors [41].

Osteoid osteoma is discussed in greater detail separately. (See "Nonmalignant bone lesions in children and adolescents", section on 'Osteoid osteoma'.)

Other tumors of the spine or spinal cord — Other tumors that may affect the spine or spinal cord are listed below [37,45]. Children with malignant spinal tumors may have systemic symptoms (eg, fever, weight loss, malaise). Those with secondary spinal tumors (eg, leukemia, neuroblastoma) may have a history of malignancy. Children with spinal cord tumors may have abnormal neurologic findings (eg, difficulty walking, sphincter dysfunction).

●Ewing sarcoma (see "Clinical presentation, staging, and prognostic factors of Ewing sarcoma")

●Osteosarcoma (see "Osteosarcoma: Epidemiology, pathology, clinical presentation, and diagnosis", section on 'Clinical presentation')

●Osteoblastoma (see "Nonmalignant bone lesions in children and adolescents", section on 'Osteoblastoma')

●Aneurysmal bone cyst (see "Nonmalignant bone lesions in children and adolescents", section on 'Aneurysmal bone cyst')

●Leukemia (see "Overview of the clinical presentation and diagnosis of acute lymphoblastic leukemia/lymphoma in children")

●Lymphoma (see "Overview of Hodgkin lymphoma in children and adolescents")

●Neuroblastoma (see "Clinical presentation, diagnosis, and staging evaluation of neuroblastoma", section on 'Clinical presentation')

●Langerhans cell histiocytosis (eosinophilic granuloma) (see "Clinical manifestations, pathologic features, and diagnosis of Langerhans cell histiocytosis", section on 'Lytic bone lesions')

●Neurofibroma (see "Neurofibromatosis type 1 (NF1): Pathogenesis, clinical features, and diagnosis", section on 'Tumors')

Vertebral osteomyelitis — Vertebral osteomyelitis is most common in adolescents but may occur in any age group. Clinical features may include pain unrelated to activity, fever, and ill appearance.

Examination findings include tenderness with percussion of the spinal dorsal process, spasm of the paraspinous muscles around the involved vertebrae, and pain with flexion or extension of the spine. Children with vertebral osteomyelitis are more likely to be febrile and ill appearing than children with discitis. (See "Hematogenous osteomyelitis in children: Clinical features and complications", section on 'Vertebral bodies and intervertebral discs' and 'Discitis' below.)

Vertebral osteomyelitis may occur as a complication of infective endocarditis.

Identification of a causal agent is crucial in selection of appropriate therapy. (See "Hematogenous osteomyelitis in children: Evaluation and diagnosis", section on 'Microbiology' and "Hematogenous osteomyelitis in children: Management", section on 'Antimicrobial therapy'.)

Tethered cord — Tethered cord occurs in children of all ages. Associated clinical features include neurologic abnormalities (eg, bladder dysfunction, leg weakness, calf muscle atrophy, diminished or absent deep tendon reflexes, dermatomal sensory loss, foot drop), recent onset scoliosis with severe pain, back pain exacerbated by exercise in older children, or refusal to perform certain activities in younger children. (See "Closed spinal dysraphism: Clinical manifestations, diagnosis, and management", section on 'Tethered cord syndrome'.)

Syringomyelia — Syringomyelia is a fluid-filled, gliosis-lined cavity within the spinal cord. It occurs in children of all ages and may be associated with congenital anomalies (eg, Arnold-Chiari malformation type 1) or spinal infection, inflammation, tumor, or trauma. Most lesions are between C2 and T9. The clinical presentation is variable and includes no symptoms, recent onset scoliosis with severe pain, and progressive central spinal cord deficits. Syringomyelia is diagnosed with MRI. (See "Disorders affecting the spinal cord", section on 'Syringomyelia'.)

Transverse myelitis — Transverse myelitis occurs in children of all ages and may be associated with infection or systemic inflammatory autoimmune disorders (eg, systemic lupus erythematosus, ankylosing spondylitis). Clinical features include abnormal motor, sensory, and/or autonomic findings. (See "Transverse myelitis: Etiology, clinical features, and diagnosis", section on 'Clinical features'.)

Vaso-occlusive pain — Vaso-occlusion and/or collapse of vertebral bodies from avascular necrosis and osteoporosis (image 3) may cause back pain in patients with sickle cell disease. In an observational study of 225 children who were evaluated in the emergency department for back pain, 13 percent had sickle cell disease with vaso-occlusive pain [1]. (See "Acute and chronic bone complications of sickle cell disease".)

Chronic nonbacterial osteomyelitis — Chronic nonbacterial osteomyelitis/chronic recurrent multifocal osteomyelitis (CNO/CRMO) is an inflammatory disorder of the bone with a peak onset between age 7 and 12 years. It is a rare cause of back pain in children.

CNO/CRMO may affect the thoracic or lumbar spine or the pelvis. The initial presentation is similar to that of osteomyelitis (eg, localized pain with increased inflammatory markers, occasionally with low-grade fever); however, by definition, blood and bone cultures do not demonstrate an infectious pathogen. Associated findings include psoriasis, palmoplantar pustulosis, acne, inflammatory bowel disease, and spondyloarthropathy. (See "Chronic nonbacterial osteomyelitis (CNO)/chronic recurrent multifocal osteomyelitis (CRMO)".)

Spinal epidural abscess — Epidural abscess is a rare infection of the central nervous system that requires prompt recognition and proper management to avoid potentially disastrous complications. (See "Spinal epidural abscess".)

The classic diagnostic triad consists of fever, spinal pain, and neurologic deficits, but few patients have all three at presentation. The symptoms of an untreated epidural abscess typically progress from back pain (often focal and severe), to root pain (described as "shooting" or "electric shocks"), to neurologic deficits (motor weakness, sensory changes, and bowel and bladder dysfunction), and finally paralysis, which quickly may become irreversible. The key to diagnosis of epidural abscess is consideration of the diagnosis. MRI is the preferred imaging modality.

Intervertebral disc calcification — Intervertebral disc space calcification is an idiopathic, presumably postinflammatory condition that typically affects preadolescent children from infancy onward [46,47]. It also may occur in patients with alkaptonuria [48]. (See "Disorders of tyrosine metabolism", section on 'Alkaptonuria'.)

Intervertebral disc calcification generally involves the cervical and/or thoracic discs. It may be an incidental imaging finding or associated with torticollis or back pain [47].

The clinical course usually is benign, although disc herniation may occur [46]. Spontaneous resolution is common [49]. (See 'Intervertebral disc herniation' below.)

LUMBAR, LUMBOSACRAL, OR SACROILIAC PAIN

Spondylolysis and spondylolisthesis — Spondylolysis (also known as "pars defect") is a unilateral or bilateral fracture in the vertebral pars interarticularis, usually in the lower lumbar vertebrae, particularly L5 (figure 2) [50,51]. With bilateral defects, the vertebral body can slip anteriorly, a condition known as spondylolisthesis (figure 3). In case series, spondylolysis (with or without spondylolisthesis) is one of the most common diagnoses in children and adolescents who present to specialty clinics with back pain, accounting for 12 to 16 percent of cases [4,25].

Spondylolysis is acquired as the bone "fatigues" from recurrent microtrauma during excessive lumbar hyperextension or repeated lumbar flexion and extension. The most common spondylolytic defects occur at the isthmus [36].

Risk factors for spondylolysis and spondylolisthesis include participation in sports that require repetitive flexion/extension or hyperextension of the spine (eg, gymnastics, dance, diving, weightlifting, figure skating, volleyball, soccer, football [linemen], and racquet sports). (See "Spondylolysis and spondylolisthesis in child and adolescent athletes: Clinical presentation, imaging, and diagnosis", section on 'Epidemiology and risk factors'.)

Spondylolysis usually presents in early adolescence and is more common in males than females. It may be asymptomatic but typically manifests as aching low back pain that is exacerbated by hyperextension and relieved with rest. The pain may extend into the buttocks and posterior thighs.

Examination findings include:

●Lumbosacral tenderness, particularly with extension or lateral bending.

●Hamstring tightness (limited passive straight-leg raising and forward bending).

●Positive one-legged hyperextension test – While standing on one leg and bending backward, pain is experienced in the ipsilateral back (picture 1); this test is neither sensitive nor specific for spondylolysis.

Spondylolysis may progress to spondylolisthesis, generally during the adolescent growth spurt. Progression is correlated with persistent back pain, flattening of normal lumbar lordosis, knee-flexed/hip-flexed gait (Phalen-Dickson sign), and lack of healing. (See "Spondylolysis and spondylolisthesis in child and adolescent athletes: Clinical presentation, imaging, and diagnosis", section on 'Clinical presentation and examination'.)

Imaging and treatment of spondylolysis are discussed separately (algorithm 1). (See "Spondylolysis and spondylolisthesis in child and adolescent athletes: Clinical presentation, imaging, and diagnosis", section on 'Diagnostic imaging' and "Spondylolysis and spondylolisthesis in child and adolescent athletes: Management".)

Hyperlordotic low back pain — Hyperlordotic low back pain (also called posterior element overuse syndrome, mechanical low back pain, or muscular low back pain) is a common cause of low back pain in adolescents [13]. It is associated with repeated extension and rotation of the spine and weak core muscles [52,53]. Clinical features include pain with extension and rotation, paraspinal muscle tenderness, and focal tenderness over the lower lumbar spine.

Intervertebral disc herniation — Intervertebral disc herniation is an uncommon cause of back pain in children and adolescents.

●Pathogenesis – Intervertebral bodies provide support and mobility for the vertebral bodies. They are composed of a tough, ligamentous outer annulus and a gelatinous inner nucleus pulposus. Intervertebral pressure and degeneration of the ligamentous fibers can lead to tearing of the annulus, herniation of the nucleus pulposus, and radicular symptoms if a nerve root is compressed. Degenerative changes without herniation are associated with pain in some adolescents and an incidental finding in others [54-56].

●Epidemiology – Herniation of the nucleus pulposus uncommon in adolescents and rare in children <10 years of age [57]. Risk factors include acute trauma, Scheuermann kyphosis, family history of disc herniation, and overweight/obesity [58-60]. Sports associated with an increased risk of disc herniation include weightlifting, wrestling, gymnastics, and collision sports (table 3) [61].

●Clinical features and diagnosis – L4-L5 and L5-S1 are the most frequently involved intervertebral discs (table 4). Pain may be exacerbated by prolonged sitting, Valsalva, and activity [6]. Additional clinical features of degenerative disc disease in children may include [58,62-65]:

•Lumbar pain, exacerbated with forward bending

•Sciatica (pain radiating below the knees)

•Limitation of spinal flexibility

•Limitation of passive straight-leg raising

•Leg pain is often worse than back pain

Severe midline disc herniations can compromise the cauda equina and result in bladder dysfunction, saddle-area anesthesia, and other findings, sometimes in the absence of compromised strength or reflexes. (See "Back pain in children and adolescents: Evaluation", section on 'Neurologic evaluation'.)

Disc herniation is usually confirmed with MRI [44]. However, the importance of imaging findings associated with disc degeneration remains unclear; herniated discs often are identified in MRI studies of patients without complaints of back pain. (See "Evaluation of low back pain in adults".)

●Treatment – Initial treatment is conservative, although surgical therapy generally is successful if indicated for severe or progressive neurologic deficits or intractable pain [66].

Apophyseal ring fracture — Apophyseal ring fracture (also called endplate avulsion fracture or slipped vertebral apophysis) occurs at the junction between the vertebral body and the cartilaginous ring apophysis before complete fusion, with avulsion of a bony fragment that is displaced into the spinal canal [57].

Apophyseal ring fracture generally occurs in adolescents and is more common in males than females. It is associated with weight lifting, activities requiring lumbar hyperflexion (eg, dancing), collision sports, wrestling, Scheuermann kyphosis, and intervertebral disc herniation [6,67].

Clinical features include acute onset of intermittent, progressive back pain that radiates to the buttocks or lower extremities, positive straight leg-raising test. Leg pain is often worse than back pain.

Discitis — Discitis refers to inflammation of the intervertebral disc. It is a rare cause of back pain in children.

●Etiology – The etiology of discitis is controversial. The general consensus, backed by scant supportive evidence, is that discitis in children usually represents low-grade infection and is on one end of the spectrum of vertebral osteomyelitis [68-71].

Although disc biopsy is not necessary for diagnosis, as many as 60 percent of biopsied discs grow bacteria, usually Staphylococcus aureus [68]. Other identified pathogens include Kingella kingae and Mycobacterium tuberculosis [71,72]. Despite the frequency of positive cultures, children often recover without antibiotic therapy [73,74].

●Epidemiology – Discitis is rare. At a single academic medical center, the incidence was one to two cases per 32,500 pediatric hospitalizations and clinic visits per year [73]. However, given the mild and nonspecific presentation of discitis, it may be underdiagnosed.

Discitis typically occurs in children younger than three to five years, but cases may occur through adolescence [69,75]. In small case series, the mean age ranged from 2.8 to 4.5 years [69,70]. The lower lumbar discs are affected most commonly, but any disc (and occasionally more than one) may be involved.

●Clinical features – Discitis typically presents with the gradual onset of irritability and back pain, limp, or refusal to crawl or walk, without systemic toxicity; fever usually is absent or low grade, although it is more common in children presenting after the age of four years [69,72,76-79]. In some patients, abdominal pain and/or vomiting may be the only complaints. Most patients have had symptoms for three or more weeks by the time discitis is diagnosed [69,70,76]. The diagnosis is occasionally made incidentally on radiographs performed to exclude intra-abdominal pathology [73].

Examination findings include [36,75,80,81]:

•Refusal to bend forward

•Percussion tenderness over the involved spine

•Hip pain and stiffness

•Loss of lumbar lordosis

•Neurologic findings (eg, decreased muscle strength or reflexes)

•Ileus (with high lesions: T8-L1)

●Laboratory features – Blood cultures usually are sterile, and the white blood cell count generally is normal. However, the erythrocyte sedimentation rate is elevated in ≥90 percent of patients [68,71,73].

●Imaging – Plain radiographs are normal at illness onset; within two to three weeks they show narrowing of the intervertebral space [44,76]. Narrowing of the joint space may be followed by destruction of the adjacent vertebral end plates and herniation of the nucleus pulposus into the vertebral body. Spontaneous anterior fusion is common in older children. Vertebral body compression or wedging is noted rarely; in severe cases, there may be complete destruction of vertebral bodies and adjacent discs [82].

Diagnosis of discitis is best made by MRI, which can define the inflammation and exclude alternative diagnoses such as vertebral osteomyelitis and tumor [77,83,84]. MRI frequently documents involvement of the disc and both adjacent vertebral end plates, suggesting significant overlap between discitis and vertebral osteomyelitis [68]. Bone scan also can localize the inflammation, but lack of specificity and imperfect sensitivity limit its utility [85]. (See "Hematogenous osteomyelitis in children: Evaluation and diagnosis", section on 'Advanced imaging'.)

●Management – Management for discitis is not standardized. Aspiration of the affected disc for culture usually is not performed. Limited retrospective data suggest that initial treatment with intravenous antibiotics until the child shows clinical improvement, followed by oral antibiotics, is associated with a somewhat earlier response and fewer relapses than is treatment with oral antibiotics or analgesia alone [68,79,86].

Empiric antibiotic therapy should be directed against S. aureus and K. kingae (eg, an antistaphylococcal agent [nafcillin/oxacillin, clindamycin, vancomycin] and a third-generation cephalosporin [cefotaxime, ceftriaxone]). Immobilization, either through bed rest or, occasionally, bracing or casting, may assist with pain control [73].

The long-term outcome usually is good, although anomalies of the disc space and adjacent vertebrae (often asymptomatic) are common findings on long-term follow-up, occurring in 50 of 55 patients in two series [87,88].

Lumbosacral transitional vertebrae (Bertolotti syndrome) — Low back pain in association with lumbosacral transitional vertebrae is called "Bertolotti syndrome" [89]. Lumbosacral transitional vertebrae is an anatomic variation in which the transverse process of the lowest lumbar vertebra fuses to varying degrees with the first segment of the sacrum. The estimated prevalence ranges from 4 to 36 percent, with a mean of 12 percent. Associated clinical features include gradual onset, poorly localized unilateral low back pain, and increased lumbar lordosis [6,89].

Sacroiliac joint infection — Bacterial arthritis of the sacroiliac joint usually occurs in late childhood. Clinical features include pain when pressure is applied over the sacrum or during a digital rectal examination and with maneuvers that twist the pelvis (ie, the FABERE test) (figure 4). (See "Bacterial arthritis: Clinical features and diagnosis in infants and children", section on 'Clinical features'.)

Inflammatory arthritis — Systemic inflammatory conditions that affect the spine and manifest as back pain include:

●Ankylosing spondylitis (see "Spondyloarthritis in children")

●Psoriatic arthritis (see "Psoriatic juvenile idiopathic arthritis: Pathogenesis, clinical manifestations, and diagnosis")

●Arthritis of inflammatory bowel disease (see "Clinical manifestations and complications of inflammatory bowel disease in children and adolescents")

●Reactive arthritis (see "Reactive arthritis")

It is important to establish the diagnosis of these conditions because therapy can provide symptomatic relief and may prevent structural injury. There may be a family history of inflammatory arthritis.

The hallmark of inflammatory disease is morning stiffness [90]. After a night's rest, the patient awakes with axial discomfort and limited mobility that improves with a hot shower or bath and usual activity and returns after periods of prolonged inactivity ("gelling"). Severe pain is most unusual. Some patients experience aching nocturnal pain that makes it uncomfortable to turn over in bed. In a series of adult patients <50 years of age with >3 months of back pain, clinical features that were helpful in distinguishing inflammatory from noninflammatory back pain included morning stiffness for >30 minutes, improvement of back pain with exercise but not with rest, awakening with back pain only during the second half of the night, and alternating buttock pain [91]. The combination of ≥2 of these clinical features was 70 percent sensitive and 81 percent specific for inflammatory back pain. The combination of ≥3 of these clinical features was 34 percent sensitive and 97 percent specific for inflammatory back pain.

On examination, sacroiliac joint tenderness may be present. Pain may be elicited by maneuvers that stress the sacroiliac joints. These maneuvers include application of simultaneous medial pressure on the anterior iliac spines and the FABERE test (figure 4) [92]. Pain from pelvic torque with the FABERE test in the absence of pain with passive motion of the hip joint suggests discomfort arising from the sacroiliac joint, but this test is neither sensitive nor specific. Full physical examination may reveal other clues to the presence of a spondyloarthropathy, such as arthritis in other joints, enthesitis (tenderness at sites of tendon insertions, most commonly at the Achilles tendon insertions), or findings suggestive of psoriasis in the skin or fingernails. (See "Spondyloarthritis in children", section on 'Clinical presentation'.)

Although inflammatory spondylitis often is human leukocyte antigen (HLA)-B27 related, testing for HLA-B27 is of limited utility because HLA-B27 is common in the normal population and absent in some patients with spondylitis [93,94]. (See "Back pain in children and adolescents: Evaluation", section on 'Targeted laboratory evaluation'.)

Sacroiliac joint changes may be observed on plain radiographs in advanced disease, but findings are typically absent at disease onset. Magnetic resonance imaging, without intravenous contrast, is the preferred first-line diagnostic modality (ie, without prior plain radiograph) because it is more sensitive for detection of early disease and avoids gonadal radiation [95-97].

PARASPINAL MUSCLE PAIN

Viral myalgia — Mild to moderate diffuse myalgias often occur during the prodrome or early phase of acute viral infections. The back is commonly involved. In an observational study of 225 children who were evaluated in the emergency department for back pain, 4 percent were diagnosed with viral illness [1]. (See "Overview of viral myositis", section on 'Clinical manifestations'.)

Pyomyositis — Paraspinous muscle abscess (pyomyositis) is characterized by fever and muscle tenderness localized to a single muscle group. It is classically an infection of young children (age 2 to 5 years) and young adults (age 20 to 45 years) in the tropics but is increasingly reported in temperate climates. Predisposing factors for pyomyositis include immunodeficiency, trauma, injection drug use, concurrent infection, and malnutrition. (See "Primary pyomyositis", section on 'Clinical manifestations'.)

REFERRED PAIN — Back pain that is not in the midline may be referred pain from:

●Pyelonephritis – Symptoms of urinary tract infection include fever, urinary symptoms (dysuria, urgency, frequency, incontinence, macroscopic hematuria), abdominal pain, and flank pain. Urinalysis and urine culture are necessary for diagnosis. (See "Urinary tract infections in infants and children older than one month: Clinical features and diagnosis", section on 'Older children'.)

●Pneumonia – Pneumonia is suggested by fever, cough, tachypnea, and pleuritic chest pain, but these findings may be absent. (See "Community-acquired pneumonia in children: Clinical features and diagnosis", section on 'Clinical presentation'.)

●Pelvic inflammatory disease – Pelvic inflammatory disease is an acute infection of the upper genital tract structures (uterus, oviducts, ovaries) that may occur in sexually active females. Pelvic examination is necessary for diagnosis. (See "Pelvic inflammatory disease: Clinical manifestations and diagnosis".)

●Nephrolithiasis – Nephrolithiasis may cause flank pain in children and adolescents. (See "Kidney stones in children: Clinical features and diagnosis", section on 'Pain'.)

●Pancreatitis – Acute pancreatitis is characterized by acute, steady upper abdominal pain. Approximately one-half of patients have band-like radiation to the back, and most have nausea and vomiting. Other features include restlessness, agitation, and relief on bending forward. (See "Clinical manifestations and diagnosis of acute pancreatitis" and "Clinical manifestations and diagnosis of chronic and acute recurrent pancreatitis in children".)

●Ureteropelvic junction obstruction – Patients with ureteropelvic junction obstruction may present with flank pain that increases during brisk diuresis (eg, after consumption of caffeine or alcohol). They also may have nausea and vomiting. (See "Congenital ureteropelvic junction obstruction".)

●Cholecystitis – Clinical features of cholecystitis include steady and severe abdominal pain in the right upper quadrant or epigastrium that may radiate to the right shoulder or back; nausea; vomiting; and anorexia. Symptoms may be precipitated by ingestion of fatty food. (See "Acute calculous cholecystitis: Clinical features and diagnosis".)

WIDESPREAD PAIN (NOT LIMITED TO THE BACK)

Pain amplification/chronic pain syndromes — Pain amplification/chronic pain syndromes (eg, fibromyalgia, complex regional pain syndrome) account for 10 to 15 percent of referrals to pediatric rheumatology practices [98-100]. Complaints limited to the back are uncommon. Most children with pain amplification/chronic pain syndromes are adolescents [101].

Hallmarks of pain amplification/chronic pain syndromes include discordance between reported symptoms and physical findings, frequent school absences, and withdrawal from social activities with peers. Pain prolonged over the course of years is common. (See "Fibromyalgia in children and adolescents: Clinical manifestations and diagnosis" and "Complex regional pain syndrome in children".)

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: Spondylolysis and spondylolisthesis".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

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

●Basics topics (see "Patient education: Scoliosis (The Basics)" and "Patient education: Kyphosis in children (The Basics)")

●Beyond the Basics topic (see "Patient education: Back pain in children and adolescents (Beyond the Basics)")

SUMMARY

●Common causes – Most back pain in children and adolescents is caused by benign musculoskeletal conditions and trauma (table 1A). Less common but potentially serious causes of back pain include infections, malignant tumors, and inflammatory arthritis (table 1B). Potentially serious causes of back pain often are associated with warning signs (table 2). (See 'Introduction' above.)

Nonspecific musculoskeletal pain and paraspinal muscle strain are the most common causes of back pain in children and adolescents. (See 'Nonspecific musculoskeletal pain and muscle strain' above.)

●Thoracic pain – Scheuermann kyphosis (figure 1 and image 2) is a common cause of thoracic spine pain in adolescents. (See 'Scheuermann (juvenile) kyphosis' above.)

●Thoracic or lumbar spine pain – Scoliosis and osteoid osteoma are common causes of thoracic or lumbar spine pain in children and adolescents. Other causes include vertebral osteomyelitis; tethered cord; syringomyelia; transverse myelitis; vaso-occlusive pain in children with sickle cell disease; chronic nonbacterial osteomyelitis/chronic recurrent multifocal osteomyelitis; spinal epidural abscess; and intervertebral disc calcification. (See 'Thoracic or lumbar spine pain' above.)

●Lumbar, lumbosacral, or sacroiliac pain – Spondylolysis (figure 2) and hyperlordotic low back pain are common causes of lumbar or lumbosacral spine pain in children and adolescents. Other causes include intervertebral disc herniation, apophyseal ring fracture, discitis, and lumbosacral transitional vertebrae (Bertolotti syndrome). Causes of sacroiliac pain in children and adolescents include sacroiliac joint infection and inflammatory arthritis. (See 'Lumbar, lumbosacral, or sacroiliac pain' above.)

●Paraspinal pain – Causes of paraspinal muscle pain include viral myalgia (common) and pyomyositis. (See 'Paraspinal muscle pain' above.)

●Referred pain and pain not limited to the back – Other causes of back pain in children include referred pain (eg, from pneumonia, severe pelvic inflammatory disease, pyelonephritis, nephrolithiasis, pancreatitis, ureteropelvic junction obstruction, cholecystitis) and pain amplification/chronic pain syndromes (eg, fibromyalgia). (See 'Referred pain' above and 'Pain amplification/chronic pain syndromes' above.)