Abstracts

Rationale: Human parechoviruses (HPeVs) are single stranded RNA viruses with characteristics similar to enteroviruses that belong to the picornaviridae family. They cause mild respiratory and gastrointestinal symptoms in older children and adults but can be a major cause of CNS infection in the neonatal period with a seasonal predilection. Starting in March 2022, we have seen 8 patients with PCR proven HPeV encephalitis with characteristic seizures and EEG features suggestive of neonatal genetic epilepsy. Although Cerebrospinal fluid (CSF)and imaging findings have been previously described, there is little emphasis on seizure presentation and EEG findings. We wish to highlight EEG and clinical features of infectious encephalitis that may mimic genetic neonatal epilepsy syndromes.

Methods: A retrospective chart review of all neonates seen at UTSW 3/18/2022-6/1/2022 suspected to have HPeV encephalitis.  _x000D_ _x000D_ Results: Term neonates (postmentrual age 37- 40 weeks) presented with a variable combination of fever, lethargy, irritability, poor oral intake, erythematous rash and focal seizures. CSF indices were normal in all patients. EEG was abnormal in all patients where performed (n=7). EEG features included dysmaturity (7/7, 100%); excessive discontinuity (6/7, 86%); excessive asynchrony (5/7, 71%); multifocal sharp transients (7/7, 100%). Focal / multifocal seizures were captured in 6/7 (86%); tonic in 4/7 (57%) and described as migrating in 2 patients. Status epilepticus was noted on EEG in 3/7 (42%) patients. In 4/7 (57%) the EEG had showed burst suppression pattern with poor state variation and voltages of < 5-10 uV/mm during the inter-burst intervals.  Repeat EEG (3-11 days post initial EEG) showed improvement in 3 of these 4 patients. MRI showed radial diffusion restriction in deep white matter, thalami and less frequently cortex mimicking imaging findings of a metabolic or hypoxic-ischemic encephalopathy (7/8). Most patient’s seizures responded within 36 hours to treatment with acute bolus doses of medications. One patient died due to diffuse edema and status epilepticus. Six patients had a normal clinical exam at discharge (two still admitted). Patients were sent home on an average of 2 antiseizure medications (phenobarbital and levetiracetam) with plans to wean phenobarbital after discharge.