Porphyria: An Uncommon Cause of Posterior Reversible Encephalopathy Syndrome

Acute intermittent porphyria (AIP) is rare and the diagnosis is often delayed. It usually presents with abdominal symptoms, behavioural changes, seizures, tachycardia, and hypertension. MRI findings are usually normal or few contrast enhancing lesions may be present. Rarely , reversible vasogenic edema is seen on MRI as T2 weighted and FLAIR hyper intensity without diffusion restriction suggestive of posterior reversible encephalopathy syndrome (PRES). Review of literature suggests that there are only few case reports of AIP associated with PRES. Because diffusion-weighted MRI is normal, the lesions are likely caused by reversible vasogenic edema and transient breakdown of the blood-brain barrier. Treatment of porphyria consists of a high carbohydrate diet supplemented with the use of intravenous glucose and haematin infusions during acute attacks. Management of seizures with commonly used anti-epileptics including phenytoin, valproic acid, carbamazepine and barbiturates can worsen symptoms or precipitate acute attacks because of their enzyme inducing activity. Levetiracetam is the preferred choice these cases. Porphyria is an important differential diagnosis in patients with unexplained abdominal pain along with neuro-psychiatric manifestations. This case report adds to a handful of cases worldwide associating AIP with radiological findings of PRES.