100+ Free Cert Rheumatology(SA) Paed Practice Questions

Explanation: This patient presents with classic oligoarticular Juvenile Idiopathic Arthritis (JIA), defined by the ILAR criteria as arthritis affecting 4 or fewer joints in the first 6 months of disease. Young girls (<6 years old) with ANA positivity and oligoarticular onset carry the highest risk (up to 30%) of developing chronic, asymptomatic anterior uveitis. Because this form of uveitis is insidious and painless, regular slit-lamp screening every 3 months is essential to detect early band keratopathy, posterior synechiae, cataracts, or glaucoma before irreversible vision loss occurs.

Explanation: Intra-articular corticosteroid injection, specifically using triamcinolone hexacetonide (TAH), is the gold-standard first-line therapy for active oligoarticular JIA. TAH is significantly superior to triamcinolone acetonide in inducing long-term clinical remission and preventing leg-length discrepancy or muscle atrophy without systemic corticosteroid side effects.

Explanation: This constellation of daily quotidian fever (spiking once or twice daily with temperature returning to normal), evanescent salmon-pink macular rash coincident with fever spikes, lymphadenopathy, organomegaly, arthritis, profound acute-phase reactant elevation (hyperferritinemia, neutrophilia, thrombocytosis, high ESR/CRP), and negative autoantibodies is classic for systemic Juvenile Idiopathic Arthritis (sJIA).

Explanation: Macrophage Activation Syndrome (MAS) is a severe, life-threatening form of secondary hemophagocytic lymphohistiocytosis (HLH) occurring in sJIA. Key diagnostic clues include a sudden paradoxically dropping ESR (due to hypofibrinogenemia from liver consumption/dysfunction), unremitting fever, profound hyperferritinemia (>684 ng/mL, often tens of thousands), cytopenias in ≥2 lineages, coagulopathy (low fibrinogen, elevated D-dimer), hepatic dysfunction, and neurological symptoms.

Explanation: Enthesitis-Related Arthritis (ERA) predominantly affects older boys (>6 years old) and is strongly associated with HLA-B27 positivity and a positive family history of HLA-B27-associated spondyloarthropathies. ERA features enthesitis (inflammation at tendon/ligament insertions such as Achilles, plantar fascia, patellar tendon) and asymmetric lower limb arthritis. Unlike oligoarticular JIA (which causes painless, insidious chronic anterior uveitis), ERA causes acute, symptomatic, painful, red anterior uveitis.

Explanation: Methotrexate is a folate antagonist that inhibits dihydrofolate reductase. Co-administration of folic acid (either 1 mg daily or 5 mg given 24-48 hours after methotrexate) significantly reduces methotrexate-induced gastrointestinal side effects (nausea, vomiting), stomatitis/oral ulceration, and hepatic transaminase elevation without compromising anti-rheumatic efficacy.

Explanation: Anti-TNF agents (such as etanercept, adalimumab, infliximab) significantly increase the risk of reactivation of latent Mycobacterium tuberculosis infection (LTBI), which is endemic in South Africa. Mandatory baseline screening includes a detailed history, Tuberculin Skin Test (TST) or IGRA (Quantiferon-TB Gold), and a chest X-ray. If LTBI is identified, prophylactic anti-tuberculosis therapy (e.g., isoniazid) must be commenced prior to initiating biologic anti-TNF therapy.

Explanation: According to ILAR criteria, Juvenile Psoriatic Arthritis is diagnosed if a child has arthritis and psoriasis, OR arthritis plus at least 2 of the following 3 minor criteria: (1) dactylitis ('sausage digit'), (2) nail pitting or onycholysis, and (3) psoriasis in a first-degree relative. This patient fulfills arthritis plus all 3 minor criteria.

Explanation: Tocilizumab is a humanized monoclonal antibody directed against the IL-6 receptor (both soluble and membrane-bound). Interleukin-6 plays a central role in driving the systemic inflammation, fever spikes, acute phase reactants, and anemia of sJIA. Tocilizumab is approved for both systemic and polyarticular JIA.

Explanation: Anakinra is a recombinant non-glycosylated human interleukin-1 receptor antagonist (IL-1Ra). Because IL-1-beta is a major driver of the hyperinflammatory storm in sJIA and MAS, high-dose IV/subcutaneous Anakinra provides rapid control of MAS and is a cornerstone therapy alongside high-dose pulse methylprednisolone and ciclosporin.