We discuss a rare case of posterior reversible encephalopathy syndrome (PRES) secondary to an acute intermittent porphyria (AIP) crisis in a 35-year-old transgender female to male patient with a history of AIP.

AIP is a rare hematological disorder due to enzyme deficiencies in heme production. AIP's hallmark features include abdominal pain, nausea, autonomic dysfunction, and neurological symptoms like neuropathy and seizures. Diagnosis relies on porphobilinogen and delta-aminolaevulinic acid levels in serum and urine. PRES is a radioclinical condition related to cerebral edema resulting in seizures and acute encephalopathy, often triggered by high blood pressure, exemplified here by a porphyria crisis.

Our patient was admitted to the hospital for signs and symptoms of pneumonia. His hospital course was complicated by seizures with further investigation finding an acute porphyria crisis due to a severe blood-stream infection, use of gender- affirming testosterone hormone therapy, and poor dentition. His crisis led to the development of PRES and subsequent status epilepticus, with significant improvement of symptoms and seizures with aggressive blood pressure management and with the use of non-porphyrogenic anti-seizure drugs, including levetiracetam and lacosamide.

Given the non-specific features of a porphyria crisis and the severity of its complications, recognizing AIP as a differential for common neurological complaints is pivotal for the prompt investigation and appropriate management for patients with porphyria. The direct interplay of hypertension from a porphyria crisis and the presumed pathophysiology of PRES with the loss of cerebral autoregulation is a key component to understanding its relation. Its significance is proven by the limitations of treatment, particularly with commonly used anti-seizure medications being porphyrogenic in nature and the complexities surrounding the management of a porphyria crisis.