From the Division of Pediatric Neurology, Department of Pediatrics (N.S., S. Sharma, M.K.), and Department of Radiodiagnosis (S. Subramanian), All India Institute of Medical Sciences, New Delhi, India.
Address correspondence and reprint requests to Dr. Naveen Sankhyan, Senior Resident, Division of Pediatric Neurology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029 India nsankhyan{at}rediffmail.com
A 42-month-old boy presented with frequent left partial motorseizures of 3 months duration. The symptoms began after an acuteepisode of fever, encephalopathy, vomiting, and left partialseizures lasting 1 week. CSF was unremarkable and negative forHSV PCR. Evaluation for procoagulant states was negative. Herecovered with left hemiparesis. MRI during the acute illness(figure 1) and at 3 months (figure 2) suggested a diagnosisof hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome.
Figure 1 T1 axial (A), T2 axial (B), and coronal (C) (FLAIR) sections of brain show thickening of cortical gray matter with increased signal intensity on T2W and FLAIR images with effacement of sulcal spaces and midline shift suggestive of unilateral encephalitis
Figure 2 T1 axial (A), T2 axial (B), and coronal (C) (T2) sections of brain showing right hemispherical atrophy with gliotic changes and ventricular dilation, as well as right subdural hematoma
HHE syndrome is characterized by prolonged unilateral convulsionswith fever in children under 4 years of age, who subsequentlydevelop hemiplegia, partial epilepsy, and extensive atrophyof the involved hemisphere.1,2 The pathogenesis is believedto be an interplay among genetic predisposition; viral infection(e.g., influenza, HHV 6) or toxin (theophylline) exposure; excitotoxicitydue to prolonged ictal activity; and contributory systemic factorssuch as cytokine excess, hypoxia, ischemia, and fever.2
Toldo I, Calderone M, Boniver C, Dravet C, Guerrini R, Laverda AM. Hemiconvulsion-hemiplegia-epilepsy syndrome: early magnetic resonance imaging findings and neuroradiological follow up. Brain Dev 2007;29:109–111.[Medline]
Mizuguchi M, Yamanouchi H, Ichiyama T, Shiomi M. Acute encephalopathy associated with influenza and other viral infections. Acta Neurol Scand 2007;115 (suppl 186):45–56.[Medline]
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