Symptom-Based Diagnosis in Pediatrics (CHOP Morning Report) 1st Ed.

CHAPTER 5. BACK, JOINT, AND EXTREMITY PAIN

MEGAN AYLOR

DEFINITION OF THE COMPLAINT

Back, joint, and extremity pain are worrisome symptoms in children. Although benign musculoskeletal disease accounts for many cases, more sinister diagnoses should be ruled out. The inability of young children to clearly describe the location and nature of the pain contributes to diagnostic difficulties. Since the diverse complaints of back, extremity, and joint pain frequently share a common etiology, a uniform approach to such symptoms facilitates accurate diagnosis.

COMPLAINT BY CAUSE AND FREQUENCY

Back pain, or discomfort anywhere along the spinal and paraspinal area, reflects potential pathology in a wide range of organ systems, including musculoskeletal, central nervous system, pulmonary, vascular, and intraabdominal or retroperitoneal structures (Table 5-1). Young children who cannot accurately localize pain require indirect symptom assessment. For example, refusal to walk, irritability with repositioning, and reluctance to participate in specific activities often provide the earliest clues to identifying back pain.

TABLE 5-1. Causes of back pain in childhood by etiology.

Infectious/Inflammatory

Vertebral ostemyelitis

Spinal epidural abscess

Diskitis

Paraspinal pyomyositis

Pneumonia

Pyelonephritis

Orthopedic

Scheuermann (juvenile) kyphosis

Spondylolysis/spondylolisthesis

Scoliosis

Intravertebral disk herniation

Trauma

Muscle strain

Rheumatologic

Juvenile ankylosing spondylitis

Juvenile rheumatoid arthritis

Neoplastic

Osteoid osteoma

Neuroblastoma

Ganglioneuroma

Lymphoma

Leukemia

Eosinophilic granuloma

Miscellaneous

Sickle cell disease

Nephrolithiasis

Alteration in gait or changes in the use of a limb also suggest an underlying extremity or joint disorder (Table 5-2). Examining one joint above and below the site of the chief complaint can prevent missing a diagnosis in cases of referred pain. For example, knee pain may be the presenting symptom for hip pathology. Joint and extremity symptoms can also represent referred pain from a spinal or paraspinal process. The radicular symptoms of nerve root entrapment in the lumbar spine may present as foot pain.

TABLE 5-2. Causes of joint or extremity pain in childhood by etiology.

Infectious/Inflammatory

Bacterial arthritis

Lyme arthritis

Disseminated Neisseria gonorrhoeae

Osteomyelitis

Pyomyositis

Acute rheumatic fever

Reactive/postinfectious arthritis

Immunization

Orthopedic

Trauma

Osteochondritis dessicans

Chondromalacia patella

Overuse syndromes

Osgood-Schlatter

Rheumatologic

Systemic juvenile idiopathic arthritis

Systemic lupus erythematosus

Dermatomyositis

Neoplastic

Leukemia

Lymphoma

Bone/soft tissue tumors

Metastatic malignancy

Hematologic

Sickle cell disease

Hemophilia

Miscellaneous

Kawasaki disease

Serum sickness

Behçet disease

Sarcoidosis

Henoch-Schönlein purpura

Guillain-Barré syndrome

Evaluation of back, extremity, and joint pain requires an understanding that extensive interplay of symptoms, findings, and etiologies exists among these diagnostic groups. Any patient with pain that interferes with activity, has associated neurologic symptoms (weakness, changes in reflexes, or bowel/bladder control), or has worrisome associated symptoms (weight loss, fever, worsening pain over time) should prompt a diagnostic evaluation.

CLARIFYING QUESTIONS

Routine inquiry into the onset, location, duration, character, radiation, and intensity of the pain may help clarify the diagnosis. Caretaker observations may supplement the history, especially in nonverbal patients. The timing of symptom onset relative to a traumatic injury can pose a particular diagnostic challenge. Many children with nontraumatic abnormalities will first notice a symptom following an insignificant injury. For example, a child with a spinal tumor may fall off a bicycle and complain of leg pain, when in fact the tumor was present for weeks, and the progressive paresis caused the child to fall from the bike. Incidental injuries are present in almost all children’s recent history and may be associated with the underlying problem, but may not necessarily be the primary cause.

Some particularly helpful questions are listed below:

• What is the age of the patient?

—In younger children, especially those under 5 years of age, back pain is often a manifestation of a serious underlying disorder. In contrast, older adolescents are more likely to have nonspecific musculoskeletal disorders similar to adults with back pain.

• What is the timing of the pain?

—Mechanical strains and stresses are often improved at night, and resolve within several weeks. However, spondylolysis, spondylolithesis, and Scheuermann disease may also improve with rest. Pain that worsens at night is more typical of neoplastic or infectious etiologies.

• Are there systemic symptoms?

—Fever, malaise, and weight loss are more suggestive of an inflammatory, neoplastic, or infectious etiology.

• Are there any neurologic findings?

—Bowel or bladder dysfunction, weakness, and changes on deep tendon reflexes are worrisome for spinal pathology such as syringomyelia, ruptured disc, or spinal cord tumor.

• Is there decreased range of motion of the back?

—Stiffness of the spine is an unusual finding in young children and may indicate infection, inflammation, or tumor. In adolescents, muscle spasm from overuse injuries limit the range of motion, but this finding resolves quickly.

• Is a deformity of the back noticeable?

—Deformity of the normal spinal curvature may represent primary spinal pathology, a congenital or idiopathic process, or muscular abnormalities that contribute to progressive scoliosis or kyphosis. Splinting during acute pneumonia leads to transient abnormal lateral curvature of the thoracic spine. Midline skin lesions such as a hemangioma, sacral dimple, or hairy patch may be useful clues to underlying spinal dysraphism.