WBR0154
| Author | PageAuthor::William J Gibson |
|---|---|
| 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 gave birth to an infant 4 weeks ago at 37 weeks gestation. The child is normal appearing and the pregnancy was without complications. The woman has a past medical history of hypertension, obesity and diabetes. She has now brought her son in after he showed increasing irritability and fever before having a seizure. 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::'''Incorrect''' - 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::Syphillus |
| Answer B Explanation | [[AnswerBExp::Incorrect - While mothers can pass syphillus onto infants during pregnancy, Syphillus infection typically has a different presentation. Syphillus infection can often be fatal to infants by causing hydrops fetalis, or will cause saber shins and characteristic facial abnormalities such as “saddle nose”, or Hutchinson’s teeth (incisors with a central notching).]] |
| Answer C | AnswerC::Cytomegalovirus |
| Answer C Explanation | AnswerCExp::'''Incorrect''' - While CMV can be passed from a mother to her child and can lead to seizures, the finding of temporal lobe enchepalitis is more specific for HSV2 infection. |
| Answer D | AnswerD::Gestational Diabetes |
| Answer D Explanation | [[AnswerDExp::Incorrect - Gestational diabetes is a condition in which women without previously diagnosed diabetes exhibit high blood glucose levels during pregnancy. Gestational diabetes does not cause seizures or temporal lobe enchepalitis in infants.]] |
| Answer E | AnswerE::HSV2 |
| Answer E Explanation | AnswerEExp::'''Correct''' - See Explanation |
| Right Answer | RightAnswer::E |
| Explanation | [[Explanation::This infant 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. These infections include Toxoplasma Gondii, Rubella, Cytomegalovirus, Herpes, HIV, and Syphilis. HSV2 infection is an infection which 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 that have newly been 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 2012 page 199 |
| Approved | Approved::Yes |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |