WBR0154

Author	[[PageAuthor::William J Gibson (Reviewed by Alison Leibowitz)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Reproductive
Prompt	[[Prompt::A 36-year-old Gravida 2 Para 2 woman with a past medical history of hypertension, obesity, and diabetes gives birth to an male at 37 weeks gestation. The child appears normal at birth and the pregnancy was without complications. Four weeks later, she brings her son to the emergency room for increasing irritability and fever that. Shortly after admission, the child develops a seizure. An MRI shows a right temporal lobe infiltrate. Which of the following is the most likely cause of the infant’s condition?]]
Answer A	AnswerA::HIV
Answer A Explanation	AnswerAExp::Infection of infants with HIV from the mother does not typically lead to such an acute presentation. Instead infants typically develop recurrent opportunistic infections later on.
Answer B	AnswerB::Syphilis
Answer B Explanation	[[AnswerBExp::While mothers can pass syphilis onto infants during pregnancy, a syphilis infection typically manifests differently than the symptoms demonstrated in this scenario. Syphilis infections can be fatal to infants when they result in hydrops fetalis. Syphilis infections can manifest in saber shins and characteristic facial abnormalities, such as “saddle noses” or Hutchinson’s teeth (incisors with a central notching).]]
Answer C	AnswerC::Cytomegalovirus
Answer C Explanation	[[AnswerCExp::While cytomegalovirus (CMV) can be passed from a mother to her child, often leading to seizures, the finding of temporal lobe encephalitis is more specific for HSV2 infection.]]
Answer D	AnswerD::Gestational Diabetes
Answer D Explanation	[[AnswerDExp::Gestational diabetes is a condition in which women, without previously diagnosed diabetes, exhibit high blood glucose levels during pregnancy. Gestational diabetes does not lead to seizures or temporal lobe encephalitis in infants.]]
Answer E	AnswerE::HSV2
Answer E Explanation	AnswerEExp::See Explanation
Right Answer	RightAnswer::E
Explanation	[[Explanation::The infant in this scenario has been infected with Herpes Simplex Virus 2, presumably from his mother. HSV2 is one of the ToRCHHeS infections, infections which can be transmitted vertically from the mother to the infant during pregnancy. The infections corresponding with the ToRCHHeS mnemonic are: Toxoplasma Gondii, Rubella, Cytomegalovirus, Herpes, HIV, and Syphilis. HSV2 infection can be asymptomatic in an infected mother, where the virus may lay dormant in the nerves of the sacral ganglia. The majority of cases (85%) occur during birth, when the baby comes in contact with infected genital secretions in the birth canal, most common with mothers recently exposed to the virus. The infected infant may display vesicular lesions on his/her skin, eyes, or mouth. Infants with CNS herpes present with seizures, tremors, lethargy, and irritability, they feed poorly, have unstable temperatures, and their fontanelle (soft spot of the skull) may bulge. CNS herpes typically causes encephalitis in the temporal lobe. Educational Objective: HSV-2 can be transmitted from mothers to infants during birth and can cause temporal lobe encephalitis. References: First Aid 2014 page 174]]
Approved	Approved::Yes
Keyword	WBRKeyword::Microbiology, WBRKeyword::Viruses, WBRKeyword::Herpes, WBRKeyword::HSV, WBRKeyword::HSV2, WBRKeyword::Encephalitis, WBRKeyword::Seizure
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