Pituitary Gland Disorders (Hyper- and Hypopituitarism) 2021-2022 PDF

Libyan International Medical University Faculty Of AMS 3rd year (2021-2022) Block 1: Endocrine Week 1. Pituitary Gland Disorders ( Hypo- and Hyperpituitarism) Dr. Rema Saad  Learning objectives 1. Define hypo- and hyperpituitarism...

Libyan International Medical University Faculty Of AMS 3rd year (2021-2022) Block 1: Endocrine Week 1. Pituitary Gland Disorders ( Hypo- and Hyperpituitarism) Dr. Rema Saad  Learning objectives 1. Define hypo- and hyperpituitarism 2. list the causes of hypo and hyperpituitarism 3. Classify pituitary adenomas and outline their main characters  Hyperpituitarism Hyperpituitarism arises from excess secretion of trophic hormones. – Hyperplasias, adenomas, and carcinomas of the anterior pituitary, secretion of hormones by nonpituitary tumors, and certain hypothalamic disorders.  CLINICAL MANIFESTATIONS OF PITUITARY DISEASE Hypopituitarism Hyperpituitarism Symptoms related to local mass effects Diseases of the posterior pituitary ! often come to clinical attention because of increased or decreased secretion of ADH and associated changes in fluid and electrolyte balances.  PITUITARY ADENOMAS AND HYPERPITUITARISM The most common cause of hyperpituitarism is an adenoma arising in the anterior lobe. Less common : include pituitary carcinomas and hypothalamic disorders.  PITUITARY ADENOMAS Found in adults – The peak is from 35 to 60 years of age. Microadenomas : are less than 1 cm in diameter Macroadenomas : they exceed 1 cm.  PITUITARY ADENOMAS Pituitary adenomas are classified on the basis of the hormones and cell type–specific transcription factors that are expressed by the tumor cells – Table 24.1 Classification of Pituitary Adenomas Robbins and Cotran pathologic basis of disease." (10th ed.) (2020).  PITUITARY ADENOMAS Some pituitary adenomas secrete two hormones (GH and prolactin being the most common combination) Rarely, pituitary adenomas are plurihormonal  Lactotroph Adenoma Prolactin-secreting lactotroph adenomas are the most common type of hyperfunctioning pituitary adenoma Accounting for about 30% of clinically recognized cases. Lactotroph Adenoma  Somatotroph Adenoma Growth hormone (GH)-secreting somatotroph adenomas are the second most common type of functioning pituitary adenoma. Somatotroph adenomas may be quite large by the time they come to clinical attention because the manifestations of excessive GH may be subtle.  Somatotroph Adenoma If a somatotroph adenoma appears in children before the epiphyses have closed, the elevated levels of GH (and IGF-1) result in gigantism. If the levels of GH are increased after closure of the epiphyses, acromegaly develops.  Corticotroph Adenoma Excess production of ACTH by functioning corticotroph adenomas leads to adrenal hypersecretion of cortisol and the development of hypercortisolism (also known as Cushing syndrome).  Hypopituitarism Hypopituitarism refers to decreased secretion of pituitary hormones, which can result from diseases of the hypothalamus or of the pituitary. 75% of the parenchyma is lost.  Causes of Hypopituitarism Tumors and other mass lesions Traumatic brain injury and subarachnoid hemorrhage Pituitary surgery or radiation Pituitary apoplexy Ischemic necrosis of the pituitary (Sheehan syndrome) (postpartum necrosis) Rathke cleft cyst Empty sella syndrome Rathke cleft cyst Empty sella syndrome:  Reference Robbins and Cotran pathologic basis of disease." (10th ed.) (2020). Pictures: https://www.nature.com/articles/nrdp201692 https://pubmed.ncbi.nlm.nih.gov/24146189/ https://link.springer.com/chapter/10.1007/978-3- 319-99817-6_14