Hyponatremia and Abdominal Pain: A Case Report of Acute Hepatic Porphyria

Acute hepatic porphyrias (AHPs) are rare metabolic disorders of heme biosynthesis that present with neurovisceral symptoms such as abdominal pain, vomiting, and hyponatremia. Diagnosis is frequently delayed due to the nonspecific nature of the symptoms and insufficient awareness of the disease. A 23-year-old woman presented with diffuse abdominal pain, vomiting, myalgias, and severe hyponatremia (Na+ 104 mmol/L). Initial workup during hospitalization was inconclusive. Given the neurovisceral presentation and features of the syndrome of inappropriate antidiuretic hormone secretion (SIADH), including hypoosmolar serum and inappropriately concentrated urine, acute porphyria was suspected. Screening with a positive Hoesch test was performed, and urine samples for porphyrin precursor analysis were collected before discharge. After discharge, results confirmed markedly elevated urinary porphobilinogen and delta-aminolevulinic acid (ALA), confirming the diagnosis of acute hepatic porphyria. She was followed up in internal medicine and metabolic diseases. Despite preventive measures, she experienced a new acute attack requiring intravenous hemin. This case highlights the diagnostic challenge of acute porphyria. Hyponatremia, often due to SIADH, and elevated creatine kinase (CK) levels can be key biochemical clues. Early suspicion and targeted testing are essential for diagnosis and timely therapy. Acute hepatic porphyria should be considered in young patients with unexplained abdominal pain, vomiting, and severe hyponatremia. Early recognition, prompt biochemical testing, and appropriate management are key to improving outcomes.