Literature Review On Double Adenom

CHAPTER ONE: LITERATURE REVIEW 1.1 INTRODUCTION
Since the first attempted parathyroidectomy in 1925 by Mandl (Mandl, 1926), there have been great changes in the surgical treatment for primary hyperparathyroidism. Hyperparathyroidism is an endocrine disorder caused by the overproduction of the parathyroid hormone. The majority of these cases (85-90%) are caused by a solitary parathyroid adenoma resulting in excessive parathyroid hormone production (Ruda et al., 2005). Other causes of raised parathyroid hormone levels are multi-glandular hyperplasia (5-10%), double adenomas (3-4%) or infrequently parathyroid carcinoma (1-2%) (Johnson et al., 2011). Overproduction of this hormone can have a substantial impact on the health of the affected individuals.

The parathyroids are small lentiform glands which normally measure approximately 6 mm in length, 3-4 mm in transverse diameter, and 1-2 mm in antero-posterior direction (Policeni et al., 2012). The weight of the parathyroid gland can vary from 10 - 78mg with an average weight of just 40mg (Gilmour & Martin, 1987). When normal in size, the glands are not easily identified on most imaging studies. In contrast, in gland hyperplasia or with parathyroid adenomas the glands are generally larger and therefore more readily identified on imaging studies. In general people have two superior and two inferior glands, which sit in pairs either side of the midline. Predominantly, they are located posterior to the thyroid gland in the tracheoesophageal groove, both of which are contained within the viseral space of the neck. They are often found within the interscapular thyroid capsule, but more commonly appear outside the thyroid capsule (Som & Curtin, 2003). However, in rare cases there may be only three glands present or even one or more supernumerary glands (Hindie et al.,