Status Epilepticus After a Long Day of White-Water Rafting in the Grand Canyon

This chapter explores the case of a woman who developed her first ever seizure, after a long day of white-water rafting on the Colorado River in the Grand Canyon. She was diagnosed with status epilepticus associated with aminolevulinic acid dehydratase deficiency porphyria. The patient was intubated and on a ventilator. Extensive evaluation of serum, spinal fluid, and urine were initially unrevealing. After approximately 90 days, a diagnosis of aminolevulinic acid dehydratase deficiency porphyria was made by red blood cell enzyme analysis. The patient had no further convulsive activity once gabapentin was initiated. Her dose was further increased in increments of no greater than 300 mg twice a week. Seizure control was significantly improved at 1800 mg/day with no significant side effects. At higher doses, the patient had significant side effects, particularly somnolence and confusion. This case represented an unusual case of partial epilepsy caused by a metabolic disorder. Seizures are not a major manifestation of the porphyrias, and the diagnosis was not made for 3 months despite appropriate screening 2 weeks after the onset of her symptoms. Gabapentin was not yet available in the USA nor was it known to be safe in treating seizures related to porphyria. Because of the desperate situation of this patient, the doctors sought and obtained compassionate use of this drug based on what was known at the time about its lack of hepatic metabolism.