Chapter 147 Evaluation of Suspected Rheumatic Disease
Rheumatic diseases are defined by the constellation of results of the physical examination, autoimmune marker and other serologic tests, tissue pathology, and imaging. Defined diagnostic criteria exist for most rheumatic diseases. Recognition of clinical patterns remains essential for diagnosis because there is no single diagnostic test and results may be positive in the absence of disease. Further clouding diagnosis, children sometimes present with partial criteria that evolve over time or with features of more than one rheumatic disease (overlap syndromes). The primary mimics of rheumatic diseases are infection and malignancy but also include metabolic, orthopedic, and chronic pain conditions. Exclusion of possible mimicking disorders is essential before initiation of treatment for a presumptive diagnosis, especially corticosteroids. After careful evaluation has excluded nonrheumatic causes, referral to a pediatric rheumatologist for confirmation of the diagnosis and treatment should be considered.
There are no classic symptoms of a rheumatic disease, but common symptoms include joint pain, fever, fatigue, and rash. Presenting signs and symptoms help direct the evaluation and limit unnecessary testing. Once a differential diagnosis is developed on the basis of history and physical findings, a directed assessment assists in determining the diagnosis.
Arthralgias are common in childhood and are a frequent reason for referral to pediatric rheumatologists. Arthralgias without physical findings for arthritis suggest infection, malignancy, orthopedic conditions, benign syndromes, or pain syndromes such as fibromyalgia (Table 147-1). Although rheumatic diseases may manifest as arthalgias, arthritis is a stronger predictor of the presence of rheumatic disease and a reason for referral to a pediatric rheumatologist. The timing of joint pain along with associated symptoms including poor sleep and interference with normal activities provides important clues. Poor sleep, debilitating generalized joint pain that worsens with activity, school absences, and normal physical and laboratory findings in an adolescent suggest a pain syndrome (e.g. fibromyalgia). If arthralgia is accompanied by a history of dry skin, hair loss, fatigue, growth disturbance, and/or cold intolerance, testing for thyroid disease is merited. Nighttime awakenings due to severe pain along with decreased platelet count or white blood cell count or, alternatively, a very high white blood cell counts may lead to the diagnosis of malignancy, especially marrow-occupying lesions such as acute lymphocytic leukemia and neuroblastoma. Pain with physical activity suggests a mechanical problem such as an overuse syndrome or orthopedic condition. An adolescent girl presenting with knee pain aggravated by walking up stairs and on patellar distraction likely has patellofemoral syndrome. Children aged 3 to 10 yr who have a history of episodic pain that occurs at night after increased daytime physical activity and that is relieved by rubbing but who have no limp or complaints in the morning likely have growing pains. There is often a positive family history for growing pains, which may aid in this diagnosis. Intermittent pain in a child, especially a girl aged 3 to 10 yr, that is increased with activity and is associated with hyperextensible joints on exam is likely benign hypermobility syndrome. Many febrile illnesses cause arthralgias that improve when the temperature normalizes, and arthralgias are part of the diagnostic criteria for acute rheumatic fever (ARF; Chapter 176.1).
|SYMPTOM||RHEUMATIC DISEASE(S)||POSSIBLE NONRHEUMATIC DISEASES CAUSING SIMILAR SYMPTOMS|
|Fevers||Systemic JIA, SLE, vasculitis, acute rheumatic fever, sarcoidosis, MCTD||Malignancies, infections and post-infectious syndromes, inflammatory bowel disease, periodic fever syndromes, Kawasaki disease, HSP|
|Arthralgias||JIA, SLE, rheumatic fever, JDM, scleroderma, sarcoidosis||Hypothyroidism, trauma, endocarditis, other infections, pain syndromes, growing pains, malignancies, overuse syndromes|
|Weakness||JDM, myositis secondary to SLE, MCTD, and deep localized scleroderma||Muscular dystrophies, metabolic and other myopathies, hypothyroidism|
|Chest pain||Juvenile rheumatoid arthritis, SLE (with associated pericarditis or costochondritis)||Costochondritis (isolated), rib fracture, viral pericarditis, panic attack, hyperventilation|
|Back pain||Spondyloarthropathy, juvenile ankylosing spondylitis||Vertebral compression fracture, diskitis, intraspinal tumor, spondylolysis, spondylolisthesis, bone marrow–occupying malignancy, pain syndromes, osteomyelitis, muscle spasm, injury|
|Fatigue||SLE, JDM, MCTD, vasculitis, JIA||Pain syndromes, chronic infections, chronic fatigue syndrome, depression|
HSP, Henoch-Schönlein purpura; JDM, juvenile dermatomyositis; JIA, juvenile idiopathic arthritis; MCTD, mixed connective tissue disease; SLE, systemic lupus erythematosus.