الفهرس 
Embryology of Parathyroid GlandsOnly 14 pages are availabe for public view
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Abstract
yperparathyroidism is a serious metabolic disorder, The incidence of hyperparathyroidism is about one in 20.000 people. The incidence of hyperparathyroidism has increased substantially, largely as a result of routine blood calcium measurement. Primary hyperparathyroidism is usually a disease of adults, most cases occur in the fifties or later in life, it is more common in women than in men, and most prevalent in postmenopausal women. Of all patients with PHPT, approximately 87% have a single adenoma while only 9% have four-gland hyperplasia, 3% have double adenomas, and 1% have parathyroid carcinoma , Although most patients with Primary Hyperparathyroidism have sporadic disease, some Patients have primary hyperpara-thyoidism associated with familial endocrinopathies, including multiple endocrine neoplasia type 1 (MEN1), multiple endocrine neoplasia type 2 (MEN 2), familial hyperparathyroidism without other endo-crinepathies and neonatal hyperparathyroidism.
The most common presentation of PHPT is the detection of unsuspected asymptomatic hypercalcemia by routine biochemical screening diagnosis of hyperparathyroidism is based upon 2 laboratory tests alone: serum calcium, and serum parathyroid hormone.
Most authors favor the measurement of ionized calcium, which is directly affected by parathyroid hormone. Ultrasonography and Technetium99m-sesta-mibi are standard modalities for imaging parathyroid lesions. A bilateral neck exploration, unilateral neck exploration or minimally invasive radio-guided parat-hyroiddectomy may be pursued conditional based on the results from these localization scans. Other pre-operative localization studies include CT scan, MRI, Technetium 99m-Tetrofosmin scanning, Thalium-Technetium subtraction scintigraphy, Positron Emi-ssion Tomography (PET) scanning, with invasive modalities like fine needle aspiration and selective angiography with venous sampling. In addition to being a valuable adjunct to confirm the completeness of parathyroid resection, the rapid PTH assay has been shown to be a useful adjunct, unilateral exploration. Some authors have used intra-operative PTH to help localize the disease in cases where a sestamibi scan has failed to identify the pathology.