WBR0190

Author	[[PageAuthor::Mahmoud Sakr M.D. (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Immunology, MainCategory::Pathophysiology
Sub Category	SubCategory::Cardiology, SubCategory::Dermatology
Prompt	[[Prompt::A neonate with severe bradycardia is rushed to the operating room for pacemaker placement. He is born to a 25-year-old African-American mother with a medical history remarkable for chronic . An EKG prior to the procedure revealed complete heart block. The baby is also noted to have several erythematous annular lesions with slight central atrophy and raised active margins that are located primarily on the scalp and periorbital area. Screening of which of the following antibodies may have helped in early treatment and prevention of this emergency situation:]]
Answer A	AnswerA::Anti-SSA/Ro and/or anti-SSB/La antibodies
Answer A Explanation	AnswerAExp::Neonatal lupus (NL) is presumed to result from transplacental passage of maternal anti-SSA/Ro and/or anti-SSB/La antibodies.
Answer B	AnswerB::Anti-RNP antibodies
Answer B Explanation	AnswerBExp::Anti-RNP antibodies are autoantibodies associated with mixed connective tissue disease and are also detected in nearly 40% of Lupus erythematosus patients. However, they're not the most common type of autoantibodies associated with NL
Answer C	AnswerC::Anti-double-stranded DNA (dsDNA) antibodies
Answer C Explanation	[[AnswerCExp::Anti-dsDNA antibodies are very specific for SLE, with studies quoting nearly 100%, and are therefore used in the diagnosis of SLE. Higher titres of anti-dsDNA antibodies are more suggestive of SLE and lower titres can be found in people without the disease. In contrast to the high specificity, estimates of 25-85% have been observed for the sensitivity of anti-dsDNA in SLE. However, they're not the most common type of autoantibodies associated with NL]]
Answer D	AnswerD::Anti-ribosomal P protein antibodies
Answer D Explanation	[[AnswerDExp::Anti-ribosomal P protein antibodies are autoantibodies directed against three phosphorylated protein (“P protein”) components of ribosomes are present in a minority of patients with systemic lupus erythematosus (SLE) and are highly specific for SLE, not NL]]
Answer E	AnswerE::Antiphospholipid antibodies
Answer E Explanation	[[AnswerEExp::Antiphospholipid syndrome is an autoimmune, hypercoagulable state caused by antiphospholipid antibodies. APS provokes blood clots (thrombosis) in both arteries and veins as well as pregnancy-related complications such as miscarriage, stillbirth, preterm delivery, or severe preeclampsia.]]
Right Answer	RightAnswer::A
Explanation	[[Explanation::Neonatal lupus is responsible for 80 to 95 percent of all cases of congenital complete heart block diagnosed in utero or in the neonatal period. The characteristic skin rash, and maternal history of SLE in addition to congenital heart block makes the diagnosis of neonatal lupus very likely. Neonatal lupus (NL) is presumed to result from transplacental passage of maternal anti-SSA/Ro and/or anti-SSB/La antibodies. Most infants with complete heart block have a mother with anti-SSA/Ro and anti-SSB/La antibodies. Screening for those antibodies would have been appropriate and may have lead initiation of in utero mineralcorticoids which has a potential usefulness in improving outcomes of neonates with NL. Educational Objective: Maternal antibodies against Ro and La are associated with complete congenital hear block in newborns. References: First Aid 2014 page 425 Finkelstein Y, Adler Y, Harel L, Nussinovitch M, Youinou P. Anti-Ro (SSA) and anti-La (SSB) antibodies and complete congenital heart block. Ann Med Interne (Paris). 1997;148(3):205-8.]]
Approved	Approved::Yes
Keyword	WBRKeyword::Lupus, WBRKeyword::Neonatal lupus, WBRKeyword::Systemic lupus erythematosus, WBRKeyword::Autoimmune, WBRKeyword::Autoantibody, WBRKeyword::Rheumatology
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