THE IMPORTANCE OF DISTINGUISHING FAMILIAL HYPOCALCIURIC HYPERCALCEMIA FROM ASYMPTOMATIC PRIMARY HYPERPARATHYROIDISM PRIOR TO NECK EXPLORATION

The increasing detection of asymptomatic hypercalcaemic patients by biochemical screening has led to an increase in the number of patients referred for neck exploration. Familial Hypocalciuric Hypercalcaemia (FHH) has emerged as an important condition to distinguish from primary hyperparathyroidism as a cause of hypercalcaemia. Patients with FHH are usually asymptomatic, have similar biochemical findings to primary hyperparathyroidism, but fail to respond to parathyroid surgery. We have studied 15 members of a large kindred with FHH. The initial diagnosis was made in the propositus after a failed neck exploration for presumed primary hyperparathyroidism. Of the 7 affected members, 2 had recurrent acute pancreatitis and 2 had incidental malignant disease with no evidence of bony involvement. Measurement of the calcium: creatinine clearance ratio provides a good method of identifying hypercalcaemic patients who might have FHH. A ratio of less than 0.013 is an indication to screen first‐degree relatives before considering neck exploration. Copyright © 1990, Wiley Blackwell. All rights reserved