Acute encephalopathy with biphasic seizures and late reduced diffusion
A 3 year-old boy who was a known case of febrile seizures was brought to our hospital with an episode of focal seizure lasting for 12 min. Child had low grade fever prior to the seizure.\nOn examination, child was febrile and in postictal drowsy state. Reflexes were brisk with plantars being flexor. No signs of meningitis or raised intracranial tension were detected. Patient was admitted in the ward and recovered from postictal state in few hours.\nAfter 3 days, child again developed an episode of complex partial seizure with perioral chewing. Subsequently, he became drowsy. On examination, child had altered sensorium and brisk reflexes. After recovery, mother also complained of diminution of child′s vision. The visual evoked potentials were normal.\nEvaluation of blood, urine, and cerebrospinal fluid were negative for an infectious etiology. Serum chemistry, complete blood count, and liver enzymes were unremarkable. An initial electroencephalogram performed few hours after the termination of seizure was normal.\nOn MRI of brain done on day 4, there were diffuse symmetric areas of restricted diffusion in bilateral cerebral hemispheres, involving mainly white matter. Adjacent cortices were also hyperintense []. Corresponding areas did not reveal any signal abnormality on T1 and T2 weighted images []. The perirolandic regions and basal ganglia were spared, excluding the diagnosis of hypoxic-ischemic injury. Also, clinically, delayed onset of encephalopathy after seizure is unusual for hypoxic-ischemic encephalopathy. Shaken infant syndrome and substance abuse or intoxication were the other differentials which were initially considered.\nHowever, typical clinical scenario of biphasic seizures along with diffusion abnormalities on MRI leads us to the diagnosis of AESD. Polymerase chain reaction for human herpes viruses 6 and 7 was not performed.\nA follow-up MRI done after 4 weeks revealed resolution of diffusion weighted abnormalities and mild generalized cerebral atrophy []. Although he had not returned to normal mental status, there was considerable clinical improvement as well.