Epidimiology
A neonate with vesicular lesions has a negative CSF HSV PCR. What is the next step in management?
Blood HSV PCR
Positive blood HSV PCR with negative CSF PCR and no systemic symptoms suggests skin-limited disease.
Following an initial infection, the virus establishes latency where?
HSV commonly establishes latency in the trigeminal ganglia after infections involving the face, lips, eyes, or nasal mucosa,.
Describe the three main clinical manifestations of neonatal HSV infection and discuss how they differ in terms of presentation and prognosis.
What is the most sensitive test to confirm HSV infection in this neonate?
HSV DNA PCR from CSF
What is a common preventive measure taken during pregnancy to reduce the risk of neonatal HSV transmission?
Answer: Antiviral therapy with acyclovir or valacyclovir during the last month of pregnancy in mothers with known HSV infections.
What is the distribution of HSV-1 and HSV-2 in causing neonatal herpes simplex virus infections.
Answer: Approximately 30% of neonatal herpes infections are caused by HSV-1, while 70% are caused by HSV-2.
A mother with a history of genital HSV gives birth vaginally at term. She had no active lesions during delivery. The neonate is asymptomatic at birth and has normal initial lab results.
What is the risk of neonatal HSV transmission in this scenario?
<1%
What are the signs of disseminated neonatal HSV infection?
Answer: Symptoms include respiratory distress, jaundice, seizures, and shock.
For how long is acyclovir typically administered in cases of neonatal HSV infection?
Answer: Neonatal HSV treatment with acyclovir is typically for a duration of 14 to 21 days, depending on the extent of the infection.
A neonate with confirmed disseminated HSV has completed 21 days of IV acyclovir. The neonate is discharged in good condition.
What is the recommended post-treatment plan?
Oral acyclovir suppressive therapy for 6 months
How does the risk of transmission from mother to newborn change between primary and recurrent maternal infections?
Answer: The risk of transmission is higher in women with primary HSV infection during pregnancy than in those with recurrent infection.
A neonate with positive CSF HSV PCR has seizures and undergoes MRI. What is the most likely finding on MRI?
Bilateral temporal lobe hyperintensities
How might the physical appearance of HSV lesions in neonates differ from those in adults?
Answer: In neonates, HSV lesions may be more diffuse and less well-defined compared to the typical clustered vesicles seen in adults.
What are the potential complications of untreated neonatal HSV infection that management seeks to prevent?
Answer: Complications include CNS damage, disseminated infection, recurrent skin lesions, and death.
Discuss the guidelines for the use of herpes simplex virus immunoglobulin in the prevention of neonatal HSV.
Answer: Currently, there are no guidelines recommending the use of HSV immunoglobulin for preventing neonatal HSV as its effectiveness is not established.
A researcher is investigating the genetic factors that influence neonatal HSV infection severity. What specific host genetic factors might they focus on to understand variations in clinical outcomes?
Answer: Research might focus on polymorphisms in genes related to the immune response, such as those encoding cytokines, chemokines, and their receptors, or genes involved in antiviral defense mechanisms like Toll-like receptors.
Can neonatal HSV be transmitted if the mother has HSV antibodies? Explain.
Answer: Yes, neonatal HSV can still be transmitted even if the mother has HSV antibodies, particularly if the infection is a newly acquired type that the mother has not developed antibodies against.
What neurological signs should prompt consideration of neonatal HSV infection?
Answer: Signs such as irritability, seizures, and poor feeding should raise suspicion for neonatal HSV, particularly CNS infection.
An infant with confirmed disseminated HSV infection is not responding to standard doses of acyclovir. What alternative treatments should be considered?
Answer: Consider higher doses of acyclovir, testing for acyclovir resistance, and potentially using alternative antivirals such as foscarnet or cidofovir under specialist advice.
What preventive measures should be taken in neonates born to mothers with active genital herpes lesions at delivery?
Answer: Preventive measures include immediate washing and isolation of the neonate from the mother until lesions are covered or resolved, administration of antiviral prophylaxis to the neonate, and close monitoring for signs of HSV infection.
Describe the seasonal variation in the occurrence of neonatal HSV infections. Which season shows a higher incidence and any theories why?
Neonatal HSV infections are more common in the winter and early spring. Theories suggest that this may be due to increased viral shedding during these months due to changes in the immune system or environmental factors.
A 5-day-old neonate presents with jaundice, hepatomegaly, and petechial rash. Blood work reveals thrombocytopenia, elevated transaminases, and coagulopathy. There is no fever or CNS involvement on initial workup. Blood HSV PCR is positive.
What is the primary mechanism of disease in disseminated neonatal HSV?
Direct viral invasion of hepatocytes and endothelium
Describe the progression of symptoms in untreated neonatal HSV infection leading to severe outcomes...
Answer: Initial symptoms like mild fever and rash may progress to severe complications such as encephalitis, disseminated infection involving multiple organs, and potentially death if untreated
Question:
A 10-day-old neonate diagnosed with HSV encephalitis was started on high-dose intravenous acyclovir (20 mg/kg every 8 hours) after MRI showed temporal lobe abnormalities and CSF HSV PCR was positive. On day 7 of therapy, the neonate continues to have focal seizures despite antiepileptic medications.
Repeat MRI shows worsening bilateral temporal lobe edema with early signs of herniation.
What is the most appropriate next step?
Increase acyclovir dose and add dexamethasone to reduce cerebral edema
A pregnant woman with documented genital herpes is approaching delivery. What are the guidelines for delivery mode to minimize the risk of transmitting HSV to the neonate?
Answer: Vaginal delivery is generally safe if there are no active lesions or prodromal symptoms at the time of labor; otherwise, cesarean delivery is recommended to minimize neonatal exposure to HSV.