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PE21.1-5 | Rheumatology — Graded Quiz
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A 6-year-old boy presents with palpable purpura over the buttocks and lower extremities, severe colicky abdominal pain with guaiac-positive stools, and arthritis of bilateral ankles. Urinalysis reveals 3+ haematuria and proteinuria. A renal biopsy is performed. Which finding on immunofluorescence confirms the diagnosis?
Dominant or co-dominant IgA mesangial deposits on immunofluorescence is the defining histological feature of IgA vasculitis (HSP) nephritis and is required for EULAR/PRINTO/PRES classification. It mirrors IgA nephropathy (Berger's disease) histologically.
HSP nephritis (IgA vasculitis nephritis) is histologically identical to IgA nephropathy. The EULAR/PRINTO/PRES 2010 classification requires IgA-dominant or co-dominant deposits on biopsy OR skin biopsy showing IgA deposits in vessel walls when clinical picture supports the diagnosis.
Granular IgG/C3 is seen in post-streptococcal GN or lupus nephritis. Linear IgG is anti-GBM disease (Goodpasture's). Pauci-immune pattern characterises ANCA-associated vasculitis (e.g. granulomatosis with polyangiitis). HSP requires IgA-dominant deposits.
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An 8-year-old previously well girl presents with fever for 8 days, conjunctival injection, strawberry tongue, hand oedema, and a polymorphous rash. Echo shows LAD Z-score of +4.8. She receives IVIG 2 g/kg over 12 hours, but fever persists 36 hours after IVIG completion. What is the most appropriate next step?
Correct. IVIG resistance (fever persisting ≥36 h after IVIG infusion) occurs in 10–15% of Kawasaki patients. The standard first step for IVIG-resistant Kawasaki is a second dose of IVIG 2 g/kg. Corticosteroids (infliximab or prednisolone) are considered for patients who fail a second IVIG course.
Kawasaki IVIG resistance: defined as persistent or recrudescent fever ≥36–48 h after completing IVIG infusion. Management stepladder: second IVIG 2 g/kg → corticosteroids (infliximab or pulse methylprednisolone) → infliximab or cyclosporine for refractory cases. Risk-scoring tools (Egami, Kobayashi, Sano) predict resistance.
High-dose aspirin in Kawasaki is used as an anti-inflammatory (80–100 mg/kg/day) in the acute phase in some protocols, but it is not the treatment for IVIG resistance. Simply observing delays treatment while coronary aneurysm risk persists. Prednisolone is a second-step consideration after second IVIG failure.
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A 14-year-old girl with SLE presents with acute deterioration: confusion, fever of 38.9°C, haemoglobin 7.5 g/dL (positive direct Coombs), platelets 45,000/µL, serum creatinine 2.8 mg/dL, and ferritin 32,000 ng/mL. Which life-threatening complication must be immediately excluded?
Correct. This clinical picture — fever, cytopenias (haemolytic anaemia, thrombocytopenia), renal failure, confusion, and markedly elevated ferritin (>10,000 ng/mL) — is the hallmark of Macrophage Activation Syndrome (MAS), a life-threatening haemophagocytic lymphohistiocytosis (HLH) variant. MAS complicates systemic JIA and SLE; very high ferritin is the key biomarker. It requires immediate recognition and aggressive treatment with high-dose steroids ± cyclosporine.
MAS (HLH variant) complicates SLE and systemic JIA. Cardinal triad: fever + cytopenias (≥2 lines) + extreme hyperferritinaemia (often >10,000 ng/mL). The HScore calculator helps quantify probability. Treatment: high-dose corticosteroids + cyclosporine; etoposide for refractory cases. Mortality is 10–20% without prompt treatment.
Class IV lupus nephritis causes renal failure but does not typically produce multi-lineage cytopenias with extreme hyperferritinaemia. Hydroxychloroquine does not cause this acute catastrophic picture. APS causes thrombosis, not a haemophagocytic picture. MAS is the diagnosis.
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A 3-year-old girl has had swelling and morning stiffness of the right knee for 10 weeks. Slit-lamp examination reveals anterior uveitis with cells and flare bilaterally. ANA is positive at 1:320. RF and anti-CCP are negative. She has no psoriasis. What is the highest risk factor for significant visual impairment in this child?
Correct. While young age, ANA positivity, and oligoarticular pattern are all risk factors for developing uveitis in JIA, the single most important determinant of visual outcome is timely detection through regular slit-lamp screening. JIA-associated uveitis is typically asymptomatic (no red eye, no pain) — by the time symptoms appear, structural damage (band keratopathy, posterior synechiae, cataract, glaucoma) may already be present.
JIA-associated uveitis is a 'silent' chronic anterior uveitis. Ophthalmology screening frequency per ACR/AAP guidelines: every 3 months for high-risk (oligoarticular, ANA+, <7 yr onset, ≤4 yr disease duration); every 6 months for intermediate risk. Topical steroids + mydriatics initially; methotrexate/anti-TNF for refractory cases.
Young age, ANA positivity, and oligoarticular pattern are risk factors for developing uveitis, but visual impairment is prevented by screening, not merely by identifying risk factors. The critical actionable intervention is regular asymptomatic screening.
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A 5-year-old boy meets classic Kawasaki Disease criteria. He is given IVIG 2 g/kg and high-dose aspirin (80 mg/kg/day in 4 divided doses). Fever resolves within 24 hours. Echocardiogram at day 2 shows no coronary abnormality. When should aspirin be changed to low-dose (3–5 mg/kg/day) and when should echocardiography be repeated?
Correct. In the absence of coronary abnormalities, high-dose aspirin is typically continued until the patient is afebrile for 48–72 hours (some protocols until day 14) and then reduced to anti-platelet low-dose (3–5 mg/kg/day). Follow-up echocardiography is performed at approximately 2 weeks and again at 6–8 weeks after illness onset to detect late-onset coronary changes.
Kawasaki aspirin protocol: high-dose (80–100 mg/kg/day) during acute phase → low-dose anti-platelet (3–5 mg/kg/day) once afebrile, continued for 6–8 weeks. Echo mandatory at diagnosis, 2 weeks, and 6–8 weeks. If no coronary abnormalities by 8 weeks, aspirin is stopped. Duration extended if coronary aneurysm persists.
High-dose aspirin is not stopped at 48 hours without transitioning to low-dose antiplatelet therapy, and echo at symptom recurrence misses silent coronary change. Continuing high-dose aspirin for 6 weeks is unnecessarily prolonged. Reducing aspirin immediately post-IVIG loses anti-inflammatory benefit during the acute inflammatory phase.
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A 13-year-old girl with 2-year history of SLE (on hydroxychloroquine + low-dose prednisolone) presents with pleuritic chest pain, fever, and an ECG showing diffuse ST elevation with PR depression. Echocardiography reveals a 10 mm pericardial effusion. Anti-dsDNA is elevated; C3/C4 are low. What is the most appropriate initial management?
Correct. This is an SLE flare with serositis (pleuropericarditis) and active serological markers (elevated anti-dsDNA, low C3/C4). The treatment is immunosuppressive — pulse IV methylprednisolone (10–30 mg/kg/day for 3 days) followed by higher-dose oral prednisolone. NSAIDs and colchicine treat idiopathic/viral pericarditis, not active lupus.
SLE flare with serositis is distinguished from viral pericarditis by active serology (elevated anti-dsDNA, low C3/C4) and systemic lupus features. Treatment is immunosuppressive (pulse steroids). Anti-dsDNA and complement (C3/C4) are the best serological flare markers — track them longitudinally.
NSAID monotherapy is insufficient for SLE-related serositis with active disease markers. Pericardiocentesis is reserved for tamponade (haemodynamic compromise, 10 mm effusion without tamponade does not require pericardiocentesis). Colchicine addresses idiopathic/viral pericarditis, not SLE immunopathology.
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A 7-year-old girl presents with 10 weeks of joint swelling in the right knee and left wrist (2 joints). She is ANA positive. Her paediatrician plans to start treatment. Which statement about methotrexate in JIA is MOST accurate?
Correct. Methotrexate (10–15 mg/m²/week, oral or SC; max 20–25 mg/week) is the first-line conventional DMARD for JIA across subtypes including polyarticular and extended oligoarticular disease. Folic acid (1–5 mg/day, given on non-MTX days) must always accompany MTX to reduce mucositis and liver toxicity, regardless of tolerance.
Methotrexate remains the cornerstone first-line DMARD for JIA (polyarticular and extended oligoarticular). Always co-prescribe folic acid. Monitor LFTs, CBC at baseline and at regular intervals. Screen for varicella immunity before starting MTX; live vaccines are contraindicated during treatment.
NSAIDs are a first-line symptomatic treatment but an NSAID trial is not a prerequisite before MTX in polyarticular or inadequately controlled oligoarticular disease. MTX is used in oligoarticular JIA with extended disease or uveitis. Folic acid reduces adverse effects of MTX and must always be co-prescribed.
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A 10-year-old boy has had palpable purpura over the lower limbs, abdominal pain, and arthritis for 3 days. He is referred by the paediatrician for consideration of corticosteroids. Which indication MOST strongly supports the use of corticosteroids in HSP?
Correct. In HSP (IgA vasculitis), corticosteroids are indicated for severe gastrointestinal involvement — particularly intractable abdominal pain, significant GI bleeding, or suspected intussusception — to shorten the duration of GI symptoms. Corticosteroids do NOT prevent or treat HSP nephritis.
HSP management summary: NSAIDs for arthritis pain; adequate hydration; corticosteroids ONLY for severe abdominal involvement (or severe orchitis). Corticosteroids do NOT prevent nephritis (evidence from RCTs is negative). Severe HSP nephritis (ISKDC Grade III–V) needs nephrology management with immunosuppression (prednisolone ± azathioprine or cyclophosphamide).
Persistent purpura alone is not a corticosteroid indication — it resolves spontaneously. Arthritis is treated with NSAIDs, not steroids. Microscopic haematuria alone does not warrant corticosteroids; significant proteinuria or nephritic-nephrotic overlap triggers nephrology input. Severe abdominal pain is the clearest indication.
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A 15-year-old girl with SLE develops bilateral malar rash, oral ulcers, and anti-dsDNA of 1:640. She has 3+ proteinuria. The paediatrician plans to confirm lupus nephritis with biopsy. Which combination of serological tests, if BOTH positive, is most specific for SLE (distinct from other autoimmune diseases)?
Correct. Anti-dsDNA (high specificity ~95%, correlates with disease activity and nephritis) combined with anti-Sm (the most specific SLE antibody, ~99% specific) provides the highest composite specificity for SLE. Both are included in SLICC 2012 and EULAR/ACR 2019 immunological criteria.
SLE antibody specificity ranking: anti-Sm (~99%) > anti-dsDNA (~95%) > anti-ribosomal P > anti-Ro/La. Anti-dsDNA is clinically most useful because it correlates with disease activity (especially nephritis). Complement C3/C4 fall with active disease and should be monitored alongside anti-dsDNA.
ANA + anti-Ro: anti-Ro is also found in primary Sjögren's syndrome — not specific to SLE as a combination. ANA + anti-histone: the hallmark of drug-induced lupus. Anti-Ro + anti-La: typical of Sjögren's syndrome and neonatal lupus, not most specific for idiopathic SLE.
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A rheumatology clinic reviews three children: Child 1: 2-year-old boy, fever ≥5 days, unilateral cervical lymph node 2 cm, bilateral conjunctivitis, macular rash, red cracked lips. Child 2: 8-year-old girl, arthritis in 6 joints for 6 months, RF positive, anti-CCP positive. Child 3: 4-year-old girl, arthritis in both knees (2 joints) for 12 weeks, ANA positive, no systemic features. Which child is at GREATEST risk for developing chronic asymptomatic uveitis causing silent vision loss?
Correct. Child 3 has oligoarticular JIA with ANA positivity — the single highest-risk profile for chronic asymptomatic anterior uveitis in paediatric rheumatology. Young age (<6 years at onset), ANA positivity, and oligoarticular subtype confer a uveitis risk of up to 30%. Child 1 (Kawasaki) has coronary risk, not uveitis. Child 2 (RF+ polyarticular) has low uveitis risk but high joint destruction risk.
Paediatric uveitis risk stratification by JIA subtype: highest risk = oligoarticular + ANA+ + age <7 yr at onset + <4 yr disease duration (screen every 3 months). Knowing which subtype carries which complication risk (uveitis vs coronary aneurysm vs joint destruction) is essential for clinical recognition and referral.
Kawasaki Disease causes coronary artery aneurysm, not chronic uveitis. RF-positive polyarticular JIA (resembling adult RA) carries low uveitis risk. Oligoarticular JIA with ANA positivity in a young child is the highest uveitis-risk profile in paediatric rheumatology.
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