Acute Porphyria Presenting as Epilepsia Partialis Continua
A 30-year-old man, known only for a generalized anxiety disorder, was brought to the emergency room on November 16, 2011, in convulsive status epilepticus preceded over the last 3 days by nausea, vomiting and headaches. Initial management included intravenous benzodiazepines and phenytoin followed by intubation and a perfusion of midazolam and propofol. The patient then evolved to EPC as he presented continuous left hand and mouth myoclonic jerks, very rarely associated with altered consciousness. EEG (fig. ) showed diffuse slowing, sometime associated with right frontotemporal periodic lateralized epileptiform discharges. MRI disclosed right hemispheric gyriform increased signal on T2-weighted images, restricted diffusion on DWI/ADC images and mild midline shift to the left. Brain PET revealed focal hypermetabolism over the right frontal and temporal lobes, and to a lesser extent in the right occipital region. Two lumbar punctures were normal. As in the first patient, bacteriological, viral serological workup as well as immunologic parameters failed to disclose a plausible cause. His condition eventually worsened, with decreased level of consciousness leading to intubation, despite large spectrum antibiotics, acyclovir, several antiepileptic drug trials (phenobarbital, levetiracetam, lacosamide, topiramate, vigabatrin, gabapentin) and immunotherapy (intravenous immunoglobulins, plasma exchanges). Diagnosis of porphyria was made when results from urine, fecal and serum porphyrins returned elevated at 3 weeks after admission. One month and a half after admission and despite hematin therapy and withdrawal of porphyrinogenic drugs, the patient eventually died from brain edema secondary to the status epilepticus, after he had suffered a porphyric attack from an isoflurane trial. Later, genetic testing confirmed HCP with a rare homozygous missense G189S mutation in the coproporphyrinogen III oxidase gene.