USMLE · Question #441
A 57-year-old woman with a history of hypertension and arthritis is referred to a rheumatologist for evaluation. A complete blood count (CBC) is normal, and a mini-chem panel shows no electrolyte abno
The correct answer is C. Drug-induced lupus. The single finding of high autoantibody titers to histones, without any other autoantibodies, is characteristic of drug-induced lupus. The most commonly implicated drugs are procainamide, hydralazine (given for hypertension), and isoniazid. Patients typically have milder disease
Question
A 57-year-old woman with a history of hypertension and arthritis is referred to a rheumatologist for evaluation. A complete blood count (CBC) is normal, and a mini-chem panel shows no electrolyte abnormalities. Her erythrocyte sedimentation rate (ESR) is elevated, and an antinuclear antibody test (ANA) is positive. Further antibody studies are performed, and the results are shown below. Anti-histones high titer Anti-double stranded DNA not detected Anti-single stranded DNA not detected Anti-SSAnot detected Anti-SSB not detected Anti-SCI-70not detected Anti-Smith not detected Anti-centromere not detected Anti-RNP not detected. Which of the following diseases is suggested by these results?
Options
- ACREST syndrome
- BDiffuse form of scleroderma
- CDrug-induced lupus
- DSj
- ESystemic lupus erythematosus (SLE)
How the community answered
(41 responses)- A5% (2)
- B2% (1)
- C78% (32)
- D2% (1)
- E12% (5)
Explanation
The single finding of high autoantibody titers to histones, without any other autoantibodies, is characteristic of drug-induced lupus. The most commonly implicated drugs are procainamide, hydralazine (given for hypertension), and isoniazid. Patients typically have milder disease than in systemic lupus erythematosus (SLE) and tend to have arthritis, pleuropericardial involvement, and, less commonly, rash. CNS and renal disease are not usually observed. CREST syndrome is a milder variant of scleroderma characterized by calcinosis, Raynaud phenomenon, esophageal dysmotility, sclerodactyly and telangiectasia. Anti-centromere antibodies are diagnostic. The diffuse form of scleroderma, also known as systemic sclerosis, causes fibrosis of the skin and internal viscera. This disorder is characterized by anti-SCI-70 and often low titers of many other autoantibodies. Sj gren syndrome is characterized by dry eyes and dry mouth. Sj syndrome in isolation is characteristically positive for anti-SS-A and anti-SS-B. If it accompanies rheumatoid arthritis, anti-RNP will be positive as well. SLE is a multisystem disorder that is distinguished from drug-induced lupus by the presence of a wide variety of autoantibodies, including anti-double stranded DNA (Anti dsDNA).
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