Infectious Disease · Neonatal Infections
The facts most likely to be tested
Neonatal Herpes Simplex Virus (HSV) transmission occurs most commonly via intrapartum exposure during passage through an infected maternal birth canal.
The SEM (Skin, Eye, and Mouth) presentation is characterized by vesicular lesions appearing within the first two weeks of life.
CNS disease manifests as seizures, lethargy, and CSF pleocytosis with elevated protein, often occurring in the second or third week of life.
Disseminated disease is the most severe form, presenting with sepsis-like syndrome, pneumonitis, hepatitis, and disseminated intravascular coagulation (DIC).
Polymerase chain reaction (PCR) of the CSF and surface swabs is the diagnostic test of choice for confirming neonatal HSV infection.
Intravenous Acyclovir is the mandatory first-line treatment for all suspected or confirmed cases of neonatal HSV.
Cesarean section is indicated if the mother has active genital lesions or prodromal symptoms at the time of labor to prevent vertical transmission.
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A 12-day-old male infant is brought to the emergency department by his mother due to poor feeding and lethargy. On physical examination, the infant is febrile and has a cluster of vesicular lesions on an erythematous base on his scalp. Laboratory studies reveal elevated liver transaminases and a low platelet count. A lumbar puncture is performed, and CSF analysis shows a lymphocytic pleocytosis with an elevated protein level.
What is the most appropriate pharmacologic management for this patient?
Intravenous Acyclovir
The patient presents with signs of disseminated HSV infection (skin lesions, hepatitis, and CNS involvement), which requires immediate initiation of high-dose intravenous acyclovir to reduce mortality and morbidity.
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Etiology / Epidemiology
Acquired via vertical transmission during delivery; highest risk with primary maternal infection.
Clinical Manifestations
Presents as SEM disease (skin, eye, mouth), CNS disease, or disseminated disease with sepsis-like syndrome.
Diagnosis
Viral culture and PCR from surface swabs and CSF are the gold standard.
Treatment
Acyclovir is the first-line treatment; do not delay pending results.
Prognosis
Disseminated disease has high mortality; survivors often suffer neurodevelopmental sequelae.
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Epidemiology & Etiology
Transmission occurs primarily during passage through the birth canal in mothers with active genital herpes. Risk is significantly higher (30-50%) in primary maternal infection compared to recurrent outbreaks (<1%). Cesarean section is indicated if active lesions are present at the onset of labor.
Pertinent Anatomy
The virus targets the skin, mucous membranes, and central nervous system. In disseminated cases, the liver and adrenal glands are primary sites of visceral involvement, leading to rapid systemic collapse.
Pathophysiology
The virus enters via mucosal surfaces or skin abrasions, leading to local replication. It spreads hematogenously to visceral organs or via retrograde axonal transport to the CNS. The cytopathic effect results in characteristic multinucleated giant cells and intranuclear inclusions.
Clinical Manifestations
Presentation is categorized into three patterns: SEM disease (vesicular rash, conjunctivitis), CNS disease (seizures, lethargy, bulging fontanelle), and disseminated disease (sepsis-like, DIC, hepatitis). The vesicular rash is a classic but absent in 20-30% of cases. Red flags include unexplained fever, irritability, and poor feeding in the first 2-3 weeks of life.
Diagnosis
The gold standard is PCR testing of surface swabs (oropharynx, eyes, rectum) and CSF. A lumbar puncture is mandatory for all infants suspected of HSV to rule out CNS involvement. Tzanck smear showing multinucleated giant cells is supportive but lacks sensitivity.
Treatment
Initiate Acyclovir immediately upon clinical suspicion; do not wait for lab confirmation. Treatment duration is 14 days for SEM disease and 21 days for CNS or disseminated disease. Monitor for neutropenia during prolonged therapy.
Prognosis
Disseminated disease carries a mortality rate of ~30% even with treatment. Survivors of CNS disease frequently experience seizure disorders, microcephaly, and developmental delay. Long-term suppressive acyclovir therapy is often required for infants with CNS involvement.
Differential Diagnosis
Bacterial Sepsis: usually presents with positive blood cultures and no vesicular rash
Enteroviral infection: often presents with aseptic meningitis and milder systemic symptoms
Varicella-Zoster: distinguished by characteristic dewdrop on a rose petal lesions
Staphylococcal scalded skin syndrome: involves skin sloughing rather than grouped vesicles
Cytomegalovirus: typically presents with periventricular calcifications and hepatosplenomegaly