VANCOUVER, British Columbia — Neuroradiological disease and clinical outcomes were not predicted by initial herpes simplex virus viral load during hospitalization, at discharge, or at long-term follow-up among patients with HSV encephalitis, according to data presented here.
“Rigorous studies of HSV load and human neurological severity have not been performed,” the researchers wrote. “Understanding these relationships may help improve therapies for this devastating disease.”
Kacy A. Ramirez, MD, assistant professor of pediatrics at Wake Forest School of Medicine, and colleagues evaluated 33 patients (20 neonates; five children; eight adults) who presented with HSV encephalitis to determine the relationship between molecular quantification of initial HSV load in cerebral spinal fluid (CSF) with radiological and clinical disease severity with HSV encephalitis.
Kacy A. Ramirez
Median age at presentation was 15 days for neonates, 5.5 years for children, and 61 years for adults. Median gestational age was 40 weeks and only 20% of neonates were premature. There was a median of 1.5 to 2 days of symptoms prior to patients seeking care.
Initial CSF viral load varied widely and was higher in adults (median 5.4 log10 copies/mL) compared with children (median 3.9 log10 copies/mL) and neonates (median 4.6 log10 copies/mL; P=.31).
Neonates with HSV type 2 had a higher initial viral load compared with those with HSV type 1 (P=.02). Greater symptom duration prior to testing resulted in higher initial viral load (P=.31). Lower odds of a favorable outcome at discharge were seen among the whole cohort (OR=0.86; 95% CI, 0.74-1.0) for persistent detectable DNA in CSF despite acyclovir, as well as among neonates alone (OR=0.87; 95% CI, 0.75-1.0), which represented prolonged viral replication or reduced CSF circulatory clearance.
“Initial load did not differ despite duration of preceding symptoms and we did not find that lesion proximity or surface area influenced viral load,” Ramirez said during the presentation. “Higher load predicted elevated protein in CSF but was not correlated with morbidity during hospitalization, magnetic resonance imaging abnormalities, discharge, or long-term outcomes.”
Initial MRI was performed a median of 4 to 8 days following symptom onset and neonates had more diffused involved compared with children and adults who had abnormalities predominately in the temporal lobes.
Higher CSF protein correlated with initial viral load among the whole cohort (P=.03) as well as neonates alone (P=.01). However, it was not associated with morbidity during hospitalization, abnormal diagnostic imaging, outcomes at discharge, or long-term outcomes.
“In conclusion, viral load was not prognostic of neuroradiological disease or clinical outcomes during hospitalization, at discharge, or long-term follow-up in patients with HSV encephalitis,” Ramirez said. “Since disease stems from viral and inflammatory components more data suggest inflammatory components may be underappreciated.” — by Amber Cox
Disclosure: The researchers report no relevant financial disclosures.