Pediatric back pain

1

Discuss the epidemiology of back pain in children compared with adults.

Traditionally, back pain in children was considered uncommon, and thought to be associated with a definable cause. Current data show that back pain is a frequent complaint in the pediatric population and that the probability of identifying a specific cause is low. Back pain is much less common before age 10, increases during adolescence, and approaches adult population rates by age 18 years. Diagnosis of a definable cause of back pain symptoms is possible in less than 20% of pediatric patients. Spinal pain in adolescence is considered to be a risk factor for spinal pain as an adult. Risk factors associated with pediatric back pain include growth acceleration, female gender, family history of back pain, backpack use, and previous back injury. Both high and low levels of physical activity are associated with increased risk of developing back pain.

2

What is the differential diagnosis of back pain in children?

• 1.

  Mechanical and traumatic disorders

  • Muscle strain

  • Overuse syndrome

  • Fracture

  • Spondylolysis/spondylolisthesis

  • Juvenile degenerative disc disease

• 2.

  Neurologic

  • Herniated disc

  • Slipped vertebral apophysis

  • Congenital spinal stenosis

• 3.

  Developmental disorders

  • Scheuermann kyphosis

  • Spondylolysis/spondylolisthesis

• 4.

  Infectious disorders

  • Discitis

  • Epidural abscess

  • Vertebral osteomyelitis

  • Tuberculosis

  • Sacroiliac joint infection

• 5.

  Rheumatologic disorders

  • Juvenile rheumatoid arthritis

  • Reactive arthritis

  • Ankylosing spondylitis

  • Fibromyalgia

• 6.

  Neoplastic disorders

  • Benign primary spine tumors

  • Malignant primary spine tumors

  • Metastatic tumors

  • Spinal cord/canal tumors

  • Tumors of muscle origin

• 7.

  Referred pain from visceral disorders

  • Pneumonia

  • Pyelonephritis

  • Retrocecal appendicitis

  • Pancreatitis

• 8.

  Nonspecific or idiopathic back pain

• 9.

  Psychogenic pain

3

What are some of the most common causes of back pain in skeletally immature patients referred to a tertiary pediatric orthopedic clinic or the emergency department?

• In the clinic : Nonspecific back pain, spondylolysis or spondylolisthesis, herniated nucleus pulposus, Scheuermann disease, spinal tumors, or infection.

• In the emergency room : Nonspecific back pain, minor trauma, spine fracture, spine infection, referred pain from visceral disorders, urinary tract infection, sickle cell crises, spondylolysis/spondylolisthesis, rheumatologic disorder, or spine tumors.

4

Why is the child’s age often helpful in narrowing the diagnosis of back pain?

No diagnosis is unique to a single age group. However, some generalizations can help in determining the most likely diagnosis:

• Younger than age 10 : Disc space infection, vertebral osteomyelitis, and tumors (Langerhans cell histiocytosis, leukemia, astrocytoma, neuroblastoma)

• Older than age 10 : Nonspecific back pain, spondylolysis, spondylolisthesis, Scheuermann kyphosis, fractures, lumbar disc herniation, apophyseal ring injury, osteoid osteoma, tumors, and spinal infections

5

What information should be obtained during a history for evaluation of back pain?

• Duration of pain symptoms (acute, >1 month, chronic)

• Location of pain (cervical vs. thoracic vs. lumbar; axial vs. radicular)

• Frequency of symptoms (intermittent, constant)

• Aggravating and alleviating factors

• Timing

• History of trauma

• Recreational activities, especially sports involving hyperextension

Red flags that should prompt further workup include:

• A history of constitutional symptoms (fever, unintentional weight loss, night sweats, malaise)

• Neurologic symptoms (numbness, weakness, bowel or bladder symptoms, gait difficulty)

• Nonmechanical pain (constant pain, night pain, pain at rest especially if not relieved by nonsteroidal antiinflammatory medications [NSAIDs])

• Pain in a child younger than age 4 years

6

How should the physical examination be performed?

The physical examination must take place with the child undressed and appropriately gowned. All systems should be examined thoroughly. The child should be observed for posture, stance, and gait. The spine should be assessed for tenderness, alignment, and flexibility. A forward bend test should be performed to assess for symmetry and flexibility. Spinal deformity (kyphosis, scoliosis) should prompt further assessment. Suspicion of underlying disease is prompted by spinal tenderness, decreased spinal range of motion, spasticity, hamstring tightness, or skin abnormalities (hemangioma, midline hair patch). The single-leg hyperextension test is a useful provocative test for diagnosis of symptomatic spondylolysis and is performed by instructing the patient to stand on one leg while extending the lumbar spine. The neurologic examination should carefully document motor strength, sensation, deep tendon reflexes, and symmetry of abdominal reflexes. The musculoskeletal examination includes assessment of all muscle groups for tenderness or limited range of joint motion.

7

What laboratory tests are useful during the evaluation of back pain in children?

Useful laboratory tests include a complete blood count (CBC) with differential, erythrocyte sedimentation rate (ESR), and C-reactive protein. These tests are recommended for young children with a history of night pain or constitutional symptoms. A blood smear test may be added to screen for leukemia. Laboratory tests for rheumatologic disorder are not routinely obtained, but when a rheumatologic disorder is considered in the differential diagnosis, additional tests include a rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP), antinuclear antibody (ANA), and HLA-B27.

8

What imaging studies play a role in evaluation of the child with back pain?

Posteroanterior (PA) and lateral radiographs of the entire spine are the preferred initial imaging study for a child with back pain. If an advanced imaging study is indicated based on clinical assessment and results of initial radiographs, the next study that should be performed is magnetic resonance imaging (MRI). Use of a technetium bone scan and computed tomography (CT) are limited to specific clinical indications due to higher radiation exposure associated with these studies.

9

When are radiographs indicated for evaluation of the child with back pain?

PA and lateral complete spinal radiographs are usually obtained after completion of a detailed history and physical examination. Additional radiographic views such as oblique or flexion-extension views are generally not indicated in the pediatric population as they do not provide additional diagnostic information and result in increased radiation exposure.

10

When is an MRI scan indicated for evaluation of a child with back pain?

MRI is the advanced imaging modality of choice for evaluation of the spinal column and neural axis. Indications for spinal MRI include back pain and an abnormal neurologic examination, radicular pain, constant pain, night pain, pain lasting >4 weeks, or back pain with constitutional symptoms. MRI is useful for defining spinal pathologies such as fracture, tumor, infection, disc herniation, spinal cord abnormalities, spondylolysis, spondylolisthesis, and Scheuermann disease. Use of contrast is indicated when infection, inflammation, or tumors are suspected. As MRI does not deliver ionizing radiation and is noninvasive, it is preferred over CT, CT-myelography, and technetium bone scans whenever possible. Disadvantages associated with MRI include the need for anesthesia when the study is performed in very young children and the danger of attributing symptoms to imaging findings that are clinically irrelevant.

11

When is a CT scan indicated for evaluation of a child with back pain?

Spinal CT provides the clearest three-dimensional depiction of bone detail of any imaging modality. However, CT does not visualize soft tissue as well as MRI, and is associated with significant radiation exposure. As CT is rapidly performed, it is a preferred modality for emergency-room evaluation. It can often be performed in young children without the need for sedation, unlike MRI. CT plays a role in assessment of spinal fractures, spondylolysis, spondylolisthesis, and spinal tumors. CT performed in combination with myelography is indicated when visualization of the spinal canal and neural elements are needed and MRI is not feasible.