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[Frequent convulsions in the post-eruptive stage of exanthem subitum]
1Department of Pediatrics, Koshigaya Hospital, Dokkyo University School of Medicine, Saitama.
Insights
Human herpesvirus 6 (HHV-6) infection can cause frequent infant convulsions after rash onset. These seizures and EEG abnormalities resolve over time, suggesting a post-infectious neurological complication.
Area of Science:
- Pediatrics
- Neurology
- Infectious Diseases
Background:
- Exanthem subitum (ES), a common childhood illness, is typically caused by human herpesvirus 6 (HHV-6).
- While typically benign, HHV-6 infection can occasionally lead to central nervous system (CNS) complications.
Observation:
- This report details three infants experiencing frequent convulsions during the post-eruptive phase of HHV-6 infection.
- Electroencephalogram (EEG) revealed abnormal epileptic discharges in all infants, which resolved within 3-18 months.
- Brain MRI in one case showed focal gliosis, with SPECT imaging indicating hypoperfusion in the affected area.
Findings:
- Cerebrospinal fluid (CSF) analysis, including PCR for HHV-6 DNA and antibody testing, was negative or showed no significant increase.
- The clinical presentation, CSF findings, EEG, and CT scans did not meet diagnostic criteria for encephalitis.
- Despite the absence of encephalitis, frequent convulsions were a prominent feature.
Implications:
- The findings suggest that frequent convulsions in the post-eruptive stage of HHV-6 infection may represent a CNS complication.
- Pathogenesis might involve not only direct viral invasion but also secondary inflammatory responses, such as vasculitis.
- This highlights the importance of considering HHV-6 as a potential cause of neurological issues beyond typical encephalitis in infants.
Abstract:
We report here three infants with frequent convulsions in the post-eruptive stage of exanthem subitum (ES) due to human herpesvirus 6 (HHV-6) infection. Postictal electroencephalogram (EEG) showed in all the patients abnormal epileptic discharges, which disappeared in the following by three to eighteen months. In one case, brain magnetic resonance imaging (MRI) revealed focal gliosis. SPECT demonstrated hypoperfusion of the lesion. In the cerebro spinal fluid (CSF) of all the patients, HHV-6 DNA was negative on polymerase chain reaction (PCR) and HHV-6 antibodies were not significantly increased. Although encephalitis has been reported to complicate primary HHV-6 infection, our patients were not diagnosed as having encephalitis because of the clinical, CSF, EEG and CT findings. However, they had frequent convulsions. Not only virus invasion but also a secondary reaction including vasculitis may cause the central nervous system complications of HHV-6 infection. Frequent convulsions may occur in the post-eruptic stage after HHV-6 infection.