WBR0082: Difference between revisions

Jump to navigation Jump to search
No edit summary
m (refreshing WBR questions)
 
(11 intermediate revisions by 3 users not shown)
Line 1: Line 1:
{{WBRQuestion
{{WBRQuestion
|QuestionAuthor=Aditya Govindavarjhulla, reviewed by [[user: Jad Al Danaf]]
|QuestionAuthor=Aditya Govindavarjhulla (Reviewed by [[user: Jad Al Danaf|Jad Al Danaf]],  {{Rim}}, and Yazan Daaboul)
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Microbiology
|MainCategory=Microbiology
Line 8: Line 8:
|MainCategory=Microbiology
|MainCategory=Microbiology
|SubCategory=Reproductive
|SubCategory=Reproductive
|MainCategory=Microbiology
|MainCategory=Microbiology
|MainCategory=Microbiology
|MainCategory=Microbiology
|MainCategory=Microbiology
Line 20: Line 21:
|MainCategory=Microbiology
|MainCategory=Microbiology
|SubCategory=Reproductive
|SubCategory=Reproductive
|Prompt=A 26 year old woman in her 16th week of pregnancy presents to the office for a routine visit. She gives a history of coming into contact with a 2 year old child who had mild maculopapular rash that "looks like measles".
|Prompt=A 26-year-old G1P0 pregnant woman with no prenatal care presents to her physician's office at 8 weeks gestation for low-grade fever and cough that started on the same day. She just returned from a trip to Africa where she was exposed 4 days ago to her sick niece who had similar symptoms, and a maculopapular rash that "looked like measles but lasted for only 3 days". Further history reveals the patient recently immigrated to the United States and did not receive her childhood vaccinations. 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 a widespread maculopapular rash on her face and trunk, along with palpable 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?
At what time during her pregnancy is she at highest risk of transmitting the rubella virus to the fetus with the risk of causing congenital rubella syndrome?
|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.  
|Explanation=Rubella is a viral illness caused by a togavirus of the genus Rubivirus and is characterized by a mild, maculopapular rash. Children usually develop few or no constitutional symptoms, but adults may experience a 1–5-day prodrome of low-grade fever, headache, malaise, mild coryza, and conjunctivitis. Postauricular, occipital and posterior cervical lymphadenopathy is characteristic and precedes the rash by 5–10 days. Arthralgia or arthritis may occur in up to 70% of adult women with rubella.
 
In pregnancy, the rubella virus travels through the blood stream of the fetus and damages the blood vessels, after transmission from the mother during the viremic stage of the infection (highest risk during first trimester). This results in ischemic injury to the cells in the germ layers. The risk of congenital infection and defects is highest during the first 12 weeks of gestation, and decreases after the 12th week of gestation with rare defects after the 20th week of gestation. If infection occurs within 0–28 days before conception, there is a 43% chance the infant will be affected. If the infection occurs within 0–12 weeks after conception, there is a 51% chance the infant will be affected. If the infection occurs within 13–26 weeks after conception there is a 23% chance the infant will be affected by the disease. Infants are not generally affected if rubella is contracted during the third trimester, or 26–40 weeks after conception.
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]].
|AnswerA=Preconception
|AnswerA=Sensorineural deafness
|AnswerAExp=If infection occurs within 0–28 days before conception, there is a 43% chance the infant will be affected. This is not the period during which the patient is at highest risk.
|AnswerAExp=The most common manifestation of congenital rubella syndrome is sensorineural deafness. The risk of sensorineural deafness in infected patients is highest in the first trimester.
|AnswerB=First trimester
|AnswerB=Turner syndrome
|AnswerBExp=If the infection occurs within 0–12 weeks after conception, there is a 51% chance the infant will be affected. The first trimester is the time period during which the patient is at highest risk of transmitting rubella to her infant.
|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 classically associated with rubella infection during pregnancy.
|AnswerC=Second trimester
|AnswerC=Down syndrome
|AnswerCExp=If the infection occurs within 13–26 weeks after conception there is a 23% chance the infant will be affected by the disease. This is not the trimester during which the patient is at highest risk.
|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. It is not classically associated with rubella infection during pregnancy.
|AnswerD=Third trimester
|AnswerD=Tetralogy of Fallot
|AnswerDExp=Infants are not generally affected if rubella is contracted during the third trimester, or 26–40 weeks after conception.
|AnswerDExp=Tetralogy of Fallot (ToF) is a congenital heart disease (CHD) caused by the anterosuperior displacement of the infundibular septum. It is characterized by the presence of 4 anomalies: Pulmonary stenosis, ventricular septal defect (VSD), right ventricular hypertrophy (RVH), and an overriding aorta. Although an associated between rubella and ToF have been described, ToF is not the most common association with rubella during pregnancy.
|EducationalObjectives=When rubella infection occurs during pregnancy, especially during the first trimester, 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.
|AnswerE=Flipper-like limbs
|References=Rubella: CDC (http://www.cdc.gov/vaccines/pubs/surv-manual/chpt14-rubella.html)
|AnswerEExp=Phocomelia (also known as flipper-limbs or seal-limbs) is a teratogenic effect of thalidomide, a medication initially prescribed to pregnant women to treat pregnancy-associated nausea and vomiting. It is associated with phocomelia (abnormal limbs) and amelia (loss of limbs) in the fetuses.
|RightAnswer=B
|EducationalObjectives=In unvaccinated pregnant women, rubella infection may lead to congenital rubella syndrome in the newborn. The syndrome may manifest as sensorineural deafness, congenital cataract and other eye abnormalities, congenital heart defects such as patent ductus arteriosus, and developmental delay.
|WBRKeyword=rubella, congenital rubella syndrome, pregnancy, fetal transmission
|References=Zgorniak-Nowosielska I, Zawilinska B, Szostek S. Rubella infection during pregnancy in the 1985-86 epidemic: follow-up after seven years. Eur J Epidemiol. 1996;12(3):303-8
|RightAnswer=A
|WBRKeyword=rubella, congenital rubella syndrome, pregnancy, fetal transmission, Microbiology, Virus, Virology, RNA virus,
|Approved=Yes
|Approved=Yes
}}
}}

Latest revision as of 23:16, 27 October 2020

 
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 with no prenatal care presents to her physician's office at 8 weeks gestation for low-grade fever and cough that started on the same day. She just returned from a trip to Africa where she was exposed 4 days ago to her sick niece who had similar symptoms, and a maculopapular rash that "looked like measles but lasted for only 3 days". Further history reveals the patient recently immigrated to the United States and did not receive her childhood vaccinations. 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 a widespread maculopapular rash on her face and trunk, along with palpable 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::Sensorineural deafness
Answer A Explanation AnswerAExp::The most common manifestation of congenital rubella syndrome is sensorineural deafness. The risk of sensorineural deafness in infected patients is highest in the first trimester.
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 classically associated with rubella infection during pregnancy.]]
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. It is not classically associated with rubella infection during pregnancy.]]
Answer D AnswerD::Tetralogy of Fallot
Answer D Explanation [[AnswerDExp::Tetralogy of Fallot (ToF) is a congenital heart disease (CHD) caused by the anterosuperior displacement of the infundibular septum. It is characterized by the presence of 4 anomalies: Pulmonary stenosis, ventricular septal defect (VSD), right ventricular hypertrophy (RVH), and an overriding aorta. Although an associated between rubella and ToF have been described, ToF is not the most common association with rubella during pregnancy.]]
Answer E AnswerE::Flipper-like limbs
Answer E Explanation [[AnswerEExp::Phocomelia (also known as flipper-limbs or seal-limbs) is a teratogenic effect of thalidomide, a medication initially prescribed to pregnant women to treat pregnancy-associated nausea and vomiting. It is associated with phocomelia (abnormal limbs) and amelia (loss of limbs) in the fetuses.]]
Right Answer RightAnswer::A
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: In unvaccinated pregnant women, rubella infection may lead to congenital rubella syndrome in the newborn. The syndrome may manifest as sensorineural deafness, congenital cataract and other eye abnormalities, congenital heart defects such as patent ductus arteriosus, and developmental delay.
References: Zgorniak-Nowosielska I, Zawilinska B, Szostek S. Rubella infection during pregnancy in the 1985-86 epidemic: follow-up after seven years. Eur J Epidemiol. 1996;12(3):303-8]]

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::