Our case outlines a Porphyria attack presenting as a seizure mimic and its diagnostic and management challenges in a patient on anticonvulsant therapy.

A 36-year-old non-verbal man with global developmental delay, primary brain dysgenesis, and medically refractory epilepsy presented to the neurology clinic with spells (type A) described as whole-body stiffening, “terror scream”, eyes rolling back, head twitching, and left arm twitching. Carbamazepine (CBZ) was started and prior Levetiracetam was weaned off and this controlled the above seizures. However, he continued to have recurrent spells (type B) of intermittent abdominal pain with loud screams and turning pale. Due to the patient's non-verbal status, his history was challenging. Per his mother, he had episodic pain attacks with vomiting for a couple of years, rashes, and a 30lb weight loss and had seen his primary care physician with a negative workup otherwise. Given his clinical picture, this prompted investigation for alternative etiologies of seizure mimics including Porphyria. Urine porphobilinogen was elevated at 141.8. The patient was admitted for hematin infusions for presumed Porphyria and neurology was to wean his CBZ (since CBZ is a strong CYP450 inducer, can result in elevated porphobilinogen). Video EEG confirmed that the pain attacks did not have an EEG correlate. The patient improved with hematin infusion, however, his childhood seizures returned at the lower doses of CBZ, so it was increased to his prior dose. On follow-up in the hematology clinic, genetic testing confirmed the diagnosis of acute intermittent porphyria.

The diagnosis of porphyria was complex due to the patient's inability to verbalize his symptoms, difficulty differentiating seizure from porphyria attacks, and complex video EEG and laboratory evaluation. This case illustrates a rare seizure mimic, important clinical consideration, and testing in improving patient outcome and reducing morbidity.