L:\usmle review 7 - Sinoe medical homepage.

(A)
(B)
(C)
(D)
(E)
CREST syndrome
Diffuse form of scleroderma
Drug-induced lupus
Sjögren syndrome
Systemic lupus erythematosus (SLE)
41. The correct answer is C. 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 (choice A) 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 (choice B), 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.
Sjögren syndrome (choice D) is characterized by dry eyes and dry mouth. Sjögren 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 (choice E) 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).
42. A 55-year-old hypertensive man develops sudden onset of excruciating pain beginning in the
anterior chest, and then radiating to the back. Over the next 2 hours, the pain moves downward
toward the abdomen. Which of the following is the most likely diagnosis