Rickets mimicker: a report of two cases of primary hyperparathyroidism in adolescence

The presentation of primary hyperparathyroidism (PHPT) in most Western countries has evolved from the classic description of ‘stones, bones, and groans’ to becoming increasingly asymptomatic as a result of more frequent serum calcium screening. However, many developing countries are still reporting predominantly symptomatic PHPT with the classic complications of skeletal disease and nephrolithiasis still being quite common. Furthermore, the exact prevalence of PHPT in children is not known but it is thought to be uncommon and the clinical presentation and outcomes in this subgroup of patients are not well described in the literature. Two cases of PHPT occurring in adolescent boys are reported. Both cases initially presented with chronic bone pain involving the lower limbs and had a long delay before the diagnosis of PHPT was confirmed. They developed progressive deformities of the lower limbs, which resembled rickets clinically. Radiological features were also suggestive of rickets. However, biochemistry confirmed parathyroid hormone mediated hypercalcaemia in both cases and after parathyroid surgery a parathyroid adenoma was confirmed histologically as the aetiology of hypercalcaemia. Therefore, PHPT occurring in adolescence may have a clinical presentation almost identical to that of rickets. All patients presenting with skeletal deformities including a rickets phenotype must have serum calcium and phosphate levels measured as part of the diagnostic workup.