A 3-week-old boy is brought to the emergency department due to a seizure. The patient was born at term to a 23-year-old woman who had no prenatal care and delivered him at home. The mother states that he was healthy until this morning, when he developed a low-grade fever. The patient has been very fussy and refused to nurse at his last feed. Subsequently, he experienced a 4-minute, generalized tonic-clonic seizure with mild perioral cyanosis. Temperature is 38.3 C (100.9 F). The patient is lethargic but arouses to painful stimuli. Pupils are equal and reactive; the anterior fontanel is full. The remainder of the physical examination is normal. Blood and urine samples are obtained and a lumbar puncture is performed, with results pending. Brain imaging reveals patchy areas of increased attenuation in the cerebral cortex and edema and hemorrhage in the left temporal lobe and brainstem; no intracranial calcifications are seen. Vertical transmission of which of the following is the most likely cause of this patient's presentation?

Question

A 3-week-old boy is brought to the emergency department due to a seizure.  The patient was born at term to a 23-year-old woman who had no prenatal care and delivered him at home.  The mother states that he was healthy until this morning, when he developed a low-grade fever.  The patient has been very fussy and refused to nurse at his last feed.  Subsequently, he experienced a 4-minute, generalized tonic-clonic seizure with mild perioral cyanosis.  Temperature is 38.3 C (100.9 F).  The patient is lethargic but arouses to painful stimuli.  Pupils are equal and reactive; the anterior fontanel is full.  The remainder of the physical examination is normal.  Blood and urine samples are obtained and a lumbar puncture is performed, with results pending.  Brain imaging reveals patchy areas of increased attenuation in the cerebral cortex and edema and hemorrhage in the left temporal lobe and brainstem; no intracranial calcifications are seen.  Vertical transmission of which of the following is the most likely cause of this patient's presentation?

Quizplus · Accepted Answer

11ec25c8_d709_e725_bc81_a503ef9438d9_MD0003_00 This patient with fever, seizure, and temporal lobe abnormalities most likely has neonatal herpes simplex virus (HSV) infection. Vertical transmission of the virus typically occurs during delivery by a mother with active genital lesions. Neonatal HSV may also be contracted in utero (rare and often fatal) or postnatally through direct exposure to a contact's active lesion (eg, cold sore). Characteristic vesicles on an erythematous base are prominent in skin-eye-mouth disease; however, cutaneous findings may be absent in CNS and disseminated disease. CNS disease, as seen in this patient, typically presents in the second or third week of life with signs of encephalitis, including seizure, lethargy, and poor feeding. A full fontanel is suggestive of increased intracranial pressure. Viral transmission through the olfactory bulb to the temporal lobe results in temporal lobe hemorrhage and edema, as seen on this patient's imaging. Lumbar puncture typically shows elevated white blood cells and normal to low glucose. The presence of red blood cells in the cerebrospinal fluid (CSF) is less common in neonates with HSV encephalitis than in older children and in adults. Empiric acyclovir is initiated while awaiting confirmatory results of HSV PCR testing of the CSF. (Choices A and E) Cytomegalovirus (CMV) and Toxoplasma gondii can cause neonatal seizures, but intracranial calcifications are seen on neuroimaging in both conditions. In addition, symptomatic congenital toxoplasmosis and CMV infection also typically present with other findings such as jaundice, hepatosplenomegaly, and chorioretinitis. (Choices B and D) Neonatal bacterial meningitis due to group B Streptococcus and Listeria monocytogenes can cause fever and seizure. Imaging findings may include cerebral edema, hydrocephalus, and abscess but not temporal lobe hemorrhage, which is highly specific for HSV. Educational objective: Neonatal herpes simplex virus infection typically results from vertical transmission during delivery. The presentation in newborns with CNS disease (ie, encephalitis) typically occurs in weeks 2-3 of life with seizure and temporal lobe hemorrhage. References: Neonatal herpes simplex virus infection. (http://www.ncbi.nlm.nih.gov/pubmed/23090462) Neonatal herpes simplex virus infections. (http://www.ncbi.nlm.nih.gov/pubmed/29544668)

A 3-Week-Old Boy Is Brought to the Emergency Department Due