WBR0082

Revision as of 16:18, 5 August 2014 by YazanDaaboul (talk | contribs)
Jump to navigation Jump to search
 
Author [[PageAuthor::Aditya Govindavarjhulla (Reviewed by Jad Al Danaf, Rim Halaby, M.D. [1], and Yazan Daaboul)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Microbiology
Sub Category SubCategory::Reproductive
Prompt [[Prompt::A 26-year-old G1P0 pregnant woman who received no prenatal care presents to her physician's office at 8 weeks gestation for low-grade fever, rash, and cough that started on the day of presentation. She just returned from a trip to Africa where she was exposed 4 days ago to her sick niece who had fever, cough, and a 3-day maculopapular rash that "looked like measles". Further history reveals the patient did not receive her childhood vaccinations due to religious beliefs. She does not smoke or drink alcohol. She does not take any medications and has no known allergies. Her blood pressure is 110/72 mmHg, heart rate is 80/min, temperature is 38.3 °C (100.9 °F), and respiratory rate is 16/min. Physical examination is remarkable for posterior auricular and occipital lymphadenopathy. Which of the following congenital disorders is most commonly associated with the infectious agent responsible for this patient's condition?]]
Answer A AnswerA::Deafness
Answer A Explanation AnswerAExp::The risk of congenital infection and defects is highest during the first 12 weeks of gestation.
Answer B AnswerB::Turner syndrome
Answer B Explanation [[AnswerBExp::Turner syndrome is caused by a genetic disorder characterized by an absence of an X chromosome due to non-dysjunction. Patient's karyotype demonstrates a 44+XO pattern. Patients with Turner syndrome often have short stature when their syndrome is left untreated, neck and shoulder webbing, and ovarian dysgenesis. Turner syndrome is also associated with bicuspid aortic valve, shield chest, coarctation of the aorta (classically preductal), cystic hygroma, and horseshoe kidney. Turner syndrome is not associated with rubella infection.]]
Answer C AnswerC::Down syndrome
Answer C Explanation AnswerCExp::Down syndrome (trisomy 21) is the most common congenital disorder resulting in live births. It is characterized by intellectual disability, prominence of the epicanthal folds, flat facies, and single palmar crease.
Answer D AnswerD::24-36 weeks
Answer D Explanation AnswerDExp::The risk of congenital infection and defects is highest during the first 12 weeks of gestation with defects rare after the 20th week of gestation.
Answer E AnswerE::After 36 weeks
Answer E Explanation AnswerEExp::The risk of congenital infection and defects is highest during the first 12 weeks of gestation with defects rare after the 20th week of gestation.
Right Answer RightAnswer::B
Explanation [[Explanation::Rubella (German measles) is an enveloped single-stranded + RNA virus that belongs to the togavirus family. Infection by rubella is characterized by a 3-day maculopapular rash that starts on the face and often spreads to the trunk and extremities, resembling the rash in measles. Among children and adults who receive no rubella vaccination, the symptoms of rubella range from a very mild symptomatic course to development of fever, cough, coryza, arthralgia, conjunctivitis, and lymphadenopathy (especially posterior auricular and occipital). These symptoms are eventually followed by a maculopapular rash, as described in this patient, and often self-resolves within 3 days.

Unvaccinated pregnant women infected with rubella are at risk of transmission of the infection to their fetuses, resulting in Congenital rubella syndrome (CRS). When rubella infection occurs during early pregnancy, serious complications, such as stillbirth and congenital cardiac defects, may result. The risks of congenital rubella syndrome decrease in the second trimester, and further in the third trimester. Congenital rubella syndrome may manifest as any/many of the following: Cataracts, congenital heart disease such as patent ductus arteriosus, congenital sensorineural deafness, and developmental delay.
Educational Objective: When rubella infection occurs during pregnancy, especially during the first 12 weeks, serious consequences can result. These include miscarriages, fetal deaths/stillbirths, and a constellation of severe birth defects known as congenital rubella syndrome (CRS). The most common congenital defects are cataracts, heart defects and hearing impairment.
References: First Aid 2014 page 163

CDC.gov [2]

Miller E, Cradock-Watson JE, Pollock TM. Consequences of confirmed maternal rubella at successive stages of pregnancy. Lancet 1982;2(8302):781–84.]]

Approved Approved::Yes
Keyword WBRKeyword::rubella, WBRKeyword::congenital rubella syndrome, WBRKeyword::pregnancy, WBRKeyword::fetal transmission, WBRKeyword::Microbiology, WBRKeyword::Virus, WBRKeyword::Virology, WBRKeyword::RNA virus
Linked Question Linked::
Order in Linked Questions LinkedOrder::