A 58-year-old hypertensive man started on hydralazine 6 months ago presents with fever, arthralgia, and pleuritic chest pain. ANA is positive at 1:320, anti-histone antibodies are strongly positive, and anti-dsDNA antibodies are negative. Serum creatinine and complement levels are normal. Which is the most appropriate next step?

• A Start prednisolone and hydroxychloroquine
• B Perform renal biopsy
• C Start cyclophosphamide for lupus nephritis prophylaxis
• D Stop hydralazine and observe for symptom resolution ✓

Explanation

Drug-induced lupus presents weeks to months after exposure with constitutional symptoms, arthralgia, and serositis, with positive anti-histone antibodies, negative anti-dsDNA, normal complement, and absence of renal and CNS involvement. Hydralazine and procainamide carry the highest risk. The definitive treatment is withdrawal of the offending drug, after which symptoms resolve over weeks without immunosuppression. Prednisolone is reserved only for severe symptoms, and biopsy or cyclophosphamide would be considered in idiopathic SLE with organ involvement, not here.

Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.