Acute intermittent porphyria presenting as posterior reversible encephalopathy syndrome: a case report

BACKGROUND: Acute intermittent porphyria (AIP) is a rare metabolic disorder of heme biosynthesis. It usually presents with abdominal pain, gastrointestinal disturbances, and neuropsychiatric manifestations. Posterior reversible encephalopathy syndrome (PRES), characterized by seizures, altered mental status, and characteristic imaging findings, is an unusual and under-recognized presentation of AIP. CASE PRESENTATION: We present the case of a 16-year-old South Asian male with a 2-month history of recurrent abdominal pain, nausea, vomiting, and constipation, who developed sudden-onset generalized tonic-clonic seizures. Initial workup revealed hyponatremia and elevated liver enzymes. MRI of the brain showed findings consistent with PRES. Further history and investigations, including elevated urinary porphobilinogen levels, confirmed the diagnosis of AIP. The patient was managed conservatively with carbohydrate loading, avoidance of precipitating factors, and antiepileptic therapy, leading to gradual clinical improvement. A repeat MRI showed partial resolution of lesions, confirming the reversibility of PRES. CONCLUSION: This case highlights the importance of considering AIP in young patients presenting with gastrointestinal and neurological symptoms. PRES as a manifestation of AIP is rare but should be recognized promptly, as early diagnosis and conservative management can lead to a favorable outcome.