A Rare Case of Familial Hypocalciuric Hypercalcemia in Patient With Pancreatitis

Familial hypocalciuric hypercalcemia (FHH) is a rare autosomal dominant condition caused by mutations in the calcium-sensing receptor gene (CASR), leading to asymptomatic hypercalcemia. Here, we report a case of hypercalcemia in a patient with acute pancreatitis, subsequently diagnosed with FHH. A 41-year-old male presented with abdominal pain and elevated pancreatic enzymes. Imaging revealed changes consistent with acute pancreatitis. Surprisingly, serum calcium was elevated, which is uncommon in acute pancreatitis. Further work-up demonstrated normal parathyroid hormone (PTH), PTH-related peptide (PTHrp), and vitamin D levels. A 24-h urinary calcium excretion of 24 mg/24 h and a calcium to creatinine clearance ratio (CCCR) of 0.002 confirmed the diagnosis of FHH. This condition is typically asymptomatic, with few complications, and is managed conservatively with patient education and genetic counselling.