La parathormone : apport dans la stratégie diagnostique et thérapeutique de l'hyperparathyroïdie primaire

Primary hyperparathyroidism (PHP) is due to one or more hyperfunctionning gland and the diagnosis is biological with a high level of PTH in conjunction with hypercalcaemia. Contribution of PTH in diagnosis is essential by a basal blood analysis, but in borderline cases with sub-normal plasma PTH and calcium, an oral calcium load test could allow a differential diagnosis from other causes of high PTH. Determination of both bioactive and inactive forms of PTH provides further informations about their balance in response to physiological requirement at the target organs. Contribution of PTH is complementary to morphological data from parathyroids imaging: with the hormonal response in samples from ultra-sound guided fine needle aspiration of nodules help to discriminate between parathyroid or thyroid tissue, and with the selective venous sampling in localizing a parathyroid nodule by a PTH cartography in difficult cases showed by imaging results with ultrasonography, scintigraphy, TDM and MRI, giving thus a “biological imaging” study. Association of imaging and biology could be an efficient procedure allowing to localize an area with a secreting abnormal parathyroid gland and specifically to demonstrate the level of PTH secretion. Contribution of quick PTH assay can be a good index of successfull or failed surgery of parathyroid adenoma, and a guide for surgeon in immediate following strategy. The post-operative control of PTH must be assumed in permanent follow-up of operated patients for their correct vitamino-calcium-PTH balance with adjuvant therapy.