Delayed diagnosis of juvenile primary hyperparathyroidism.

Primary hyperparathyroidism (PHP) is most common in adults in the fifth and sixth decades of life, but is seen infrequently in adolescence and is extremely rare in children under the age of 14 years. We report the case of a young female whom we suspect had PHP from the age of 6 years. This condition remained undiagnosed for the next 11 years in spite of repeated hospital admissions. The hypercalcaemia which was initially labelled as 'idiopathic' was eventually found to be secondary to a parathyroid adenoma, which was treated successfully by surgery. The case illustrates two important advances: (1) in parathyroid hormone measurement with a new sensitive immuno-radiometric assay, and (2) in the development of radionuclide scanning for localization of parathyroid adenoma(s). No case of hypercalcaemia should be labelled as 'idiopathic' or left unexplained without a detailed exploration of the neck to exclude PHP arising from a parathyroid adenoma.