WBR0775

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pathophysiology
Sub Category	SubCategory::Gastrointestinal, SubCategory::Musculoskeletal/Rheumatology
Prompt	[[Prompt::A 48 year old woman presents to the clinic for 3 weeks of difficulty swallowing associated with severe chest pain. The woman explains that she doesn’t remember when her symptoms started, but they have been gradually increasing. Initially she had minor difficulty swallowing liquids that progressed to solid and liquid dysphagia. She explains that she sometimes has associated chest pain that resembles a heart attack and comes on every time she swallows. She has lost 11 pounds in the last 2 weeks because she has stopped eating. Physical exam is mostly unremarkable except for the findings on both her hands shown below. What antibody is most likely to be positive in this patient? ]]
Answer A	AnswerA::Anti-ribonucleoprotein antibody
Answer A Explanation	AnswerAExp::Anti-ribonucleoprotein is usually detected in 40% of patients with SLE.
Answer B	AnswerB::Anti-Jo1 antibody
Answer B Explanation	AnswerBExp::Anti-Jo1 antibodies are found in 30-40% of patients with polymyositis and to a lesser extent in patients with dermatomyositis.
Answer C	AnswerC::Anticentromere antibody
Answer C Explanation	AnswerCExp::Anticentromere is seen in 60-70% of patients with limited scleroderma (CREST) and around 10% of patients with the diffuse form.
Answer D	AnswerD::Anti-double stranded DNA antibody
Answer D Explanation	AnswerDExp::Anti-dsDNA antibodies are very specific for SLE and are involved in the pathogenesis of lupus nephritis.
Answer E	AnswerE::Anti-histone antibody
Answer E Explanation	AnswerEExp::Anti-histone antibodies are seen in drug induced lupus.
Right Answer	RightAnswer::C
Explanation	[[Explanation::Scleroderma defines a systemic disease that is characterized by thickening and fibrosis of the skin and internal organs to varying extents depending on the subtypes. Two major forms of scleroderma exist: Limited scleroderma (CREST Syndrome) and diffuse scleroderma. CREST syndrome defines a milder form referring to a clinical pentad of Calcinosis, Raynaud's phenomenon, Esophageal dysfunction, Sclerodactyly, and Telangiectasia, hence the term. The diffuse form is usually more rapidly progressive, involving large areas of skin and several internal organs. The prognosis of CREST syndrome is usually better than the diffuse form although both can be complicated by pulmonary hypertension. The etiology for both forms is unknown. Patients with CREST syndrome usually have anti-centromere antibodies while patients with diffuse scleroderma have anti-topoisomerase antibodies (anti-scl70). Treatment is symptomatic. Learning objective: CREST syndrome is the limited form of scleroderma presenting with calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia. Patients are usually is positive for anti-centromere antibody. References: Gabrielli A, Avvedimento EV, Krieg T. Scleroderma. N Engl J Med. 2009;360(19):1989-2003. Educational Objective: References: ]]
Approved	Approved::No
Keyword	WBRKeyword::CREST Syndrome, WBRKeyword::Limited Scleroderma, WBRKeyword::Systemic sclerosis, WBRKeyword::Anti-centromere antibody
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