Joint swelling in child is termed arthritis, whereas joint pain without signs of inflammation is referred to as arthralgia. Rheumatologists call pain at ligament and tendon insertions endthesopathy. Arthritis occurs in about 2 in 1000 children. The causes of swollen joints in children are numerous. In most cases, the diagnosis is established through the approach outlined below.
History Ask the patient and family about systemic symptoms, night pain, morning stiffness, other illnesses, family history, duration, severity, and general health.
Examination Perform a careful screening examination. Is the child systemically ill? Carefully examine all extremities to determine if any other large or small joints are involved. Note the degree of inflammation, localization of tenderness, joint range of motion, and any fixed deformities.
Laboratory studies If one suspects juvenile rheumatoid arthritis, order a CBC, ESR, CRP, ANA, RF, and urinalysis. Order other studies to help separate your short-list differential diagnosis.
Imaging Start with conventional radiographs and add other studies as appropriate.
Joint aspiration Joint aspiration is indicated if an infectious etiology is included in the differential diagnosis.
Clinical Types of Joint swelling in child
Polyarticular JRA occurs in two clinical patterns: young girls and those in adolescence with multiple small and large joint involvement.
Pauciarticular JRA is the most common type of juvenile arthritis. The patient is most likely a 1- to 4-year-old girl. About a quarter have no pain but are seen because of a swollen joint such as the knee, ankle, and fingers. ANA is positive in 70%, RF negative. About 20% have iritis. Early referral of these patients to an ophthamologist is essential.
Systemic JRA occurs in boys and girls usually between 3 and 10 years. These children are febrile, toxic; have severe myalgias, enlarged nodes, liver, and spleen; and sometimes have pericarditis, myocarditis, disseminated intravascular coagulation, and polyarthritis. Some cases resolve in months; others persist, causing joint destruction and disability.
Seronegative spondyloarthropathies Seronegativity is an absence of a rheumatoid factor. These disorders include ankylosing spondylitis, reactive synovitis, Reiter syndrome, and those associated with inflammatory bowel disease and psoriasis. These patients are frequently HLA-B27 positive and are usually adolescent boys. These patients may have low-grade systemic signs of fever, weight loss, and malaise.
Ankylosing spondylitis This condition is most common in adults but does occur in older children. Inflammation involves the spine, SI, and large joints. Back pain and morning stiffness in joints are common complaints. Stiffness on forward bend test is found. Laboratory findings usually include a mildly elevated ESR and CRP, a positive HLA-B27, and negative ANA and RF. Radiographic changes are late.
Reiter syndrome The triad of urethritis, arthritis, and conjunctivitis are usually found. Painful photophobic iritis can occur. The disease usually follows dysentery or a sexually transmitted disease.
Intraarticular triamcinolone hexacetonide (steroid) injections are effective in reducing synovitis and sometimes preventing joint destruction.
Confusion with trauma A swollen joint is frequently thought to be secondary to an injury. As injuries are a daily occurrence in the lives of children, a history of an injury is common. Swollen joints are seldom the result of an injury. They require evaluation and an accurate diagnosis.
Iritis can accompany pauciarticular and some polyarticular forms of JRA. The iritis is usually asymptomatic and can lead to blindness. Children with these forms of arthritis should be referred to an ophthalmologist. The risk of iritis makes an early diagnosis of arthritis of great importance.
Missing septic etiology Permanent joint damage is most likely to occur quickly from septic arthritis. Septic arthritis of the hip is most difficult to differentiate. Monarticular arthritis of the hip is seldom due to JRA.
Missing leukemia Bone and joint complaints are the initial symptoms in 20% of children with leukemia. Leukemia causes bone pain, systemic illness, high ESR, and anemia.