Unmasking Osmotic Demyelination Syndrome/Extrapontine Myelinolysis in Acute Intermittent Porphyria: Preventable Complications-Challenges in Diagnosis and Management.

Acute intermittent porphyria (AIP) is a dominant mendelian disorder caused due to deficiency of the enzyme porphobilinogen deaminase. It classically presents with pain abdomen, hypertensive crisis, electrolyte imbalance, mostly hyponatremia, and neuropsychiatric involvement. We report a case of a 12-year-old boy with AIP who experienced an acute crisis and later developed altered sensorium and seizures. Upon evaluation, he was found to have severe hyponatremia, which was secondary to the syndrome of inappropriate antidiuretic hormone secretion. His condition was corrected with intravenous hypertonic saline, and his sodium levels normalized over 2-3 days. Despite the successful correction of sodium levels, he developed extrapyramidal symptoms a week later. Magnetic resonance imaging of the brain revealed extrapontine myelinolysis. He was treated with intravenous steroids, which led to significant improvement. At 1-month follow-up, there were no neurological deficits.