Endocrine Abstracts

Primary hyperparathyroidism (PHPT) is the third common disorder of the endocrine system. It reaches a peak incidence between ages 50–60. Biochemical screening has increased its incidence up to one per 1000 (USA), and most cases are presented with asymptomatic mild hypercalcemia. The most common cause in affected individuals is a functioning single parathyroid adenoma. In advanced cases, bones (brown tumours, osteitis fibrosa cystica) and the kidney (nephrolithiasis, nephrocalcinosis) as well as many organ systems may be affected by hyperparathyroidism and associated hypercalcemia. Concomitant vitamin D deficiency might mask hypercalcemia and if remains untreated, may exacerbate postoperative hungry bone syndrome and hypocalcemia.The biochemical diagnosis basicly depends on demonstration of elevated or inappropriately normal serum parathyroid hormone concentrations in a hypercalcemic patient. Guidelines for the management of asymptomatic hyperparathyroidism has been revised in recent years, the latest being issued in 2014. Based on these criteria, a patient with asymptomatic PHPT should be given to surgery if he/she fulfils one of the following: i) serum calcium exceeding 1.0 mg/dl (0.25 mmol/l) above the upper limit of normal range, ii). BMD by DXA:T-score <−2.5 at lumbar spine, total hip, femoral neck or distal 1/3 radius, iii) vertebral fracture by X-ray, CT, MRI or vertebral fracture assessment (VFA) iv)creatinine clearance <60 cc/min, v) 24 h urinefor calcium >400 mg/day and increased stone risk by chemical analysis, vi) presence of nephrolithiasis or nwphrocalcinosis by X-ray, USG or CT, vii) age <50. The minimally invasive approach has recently gained popularity for parathyroidectomy. Various imaging techniques may be used to preoperatively localise the adenomas such as Tc99m-sestamibi SPECT CT, CT scan, MRI and ultrasonography. Intraoperative assessment of PTH is very useful to determine the success of such surgery. Patients who refuse or who are not good candidates for surgery may be followed by calcimimetic agent cinacalcet which is useful to reduce serum calcium level. Bisphosphonates are in widely used for patients in an attempt to increase BMD and reduce the risk of fragility fracture. If there is no intention to reduce calcium or increase BMD, the patient may be followed without any medication.