"Electrocuted" hippocampus after status epilepticus

A case report of a patient with an "electrocuted" hippocampus after prolonged partial status epilepticus suggests that prolonged seizures are the cause, rather than the consequence, of hippocampal damage.The 52-year-old woman with a history of partial-complex seizures experienced an increased frequency of seizures after a change in therapy. She was admitted to hospital with focal motor seizures of the right arm, which became almost continuous despite repeated intravenous lorazepam and phenytoin. After being transferred to the authors' hospital seven days later, she was found to be hemiplegic and aphasic between seizures. Electroencephalogram showed continuous sharp wave activity involving the left hemisphere. She was intubated and treated with intravenous propofol to stop the seizures and induce a therapeutic coma. Her therapy was modified during the five-day induced coma, and three days after extubation, the seizures stopped. Over the next four months, she had no seizures, but had severe impairment of long-term memory, with learning and verbal recall deficit.An MRI four months after discharge showed a complete resolution of cortical, cerebellar, and thalamic signal changes, but severe atrophy of the left hippocampal gyrus and uncus, which was not evident on an MRI conducted a year earlier.The authors say, "The hippocampus is the most vulnerable region in status epilepticus, and hippocampal sclerosis is the most common pathological abnormality found in specimens following temporal lobectomy for intractable partial epilepsy; whether this is the cause or consequence of repeated seizures has been debated for years. Our patient provides further evidence that prolonged seizures induce hippocampal damage" They describe the findings from animal studies on the processes that may lead to hippocampal neuronal death and atrophy in status epilepticus, which involve cellular influx of sodium and calcium ions, oedema, and biochemical changes. The authors conclude, "Status epilepticus is a potentially dangerous condition that can lead to hippocampal 'electrocution', hippocampal sclerosis, irreversible neuropsychological deficits, and eventually intractable epilepsy, and should, therefore, be halted as quickly as possible."Reference...