This sqadia.com medical video lecture pituitary gland focuses on the pathology of pituitary gland. This lecture explains the abnormalities associated with the hormones. Dr. Ammar-Ul-Hassan explains that how the condition hypopituitarism arises, how mutation in genes leads to inherited isolated growth hormone deficiency. Also, pituitary adenomas, central and nephrogenic diabetes insipidus are discussed respectively.
The hormones released by anterior pituitary are FSH and LH, GH, TSH, prolactin, and ACTH. The condition in which pituitary gland do not release enough amount of one of these hormones is referred to as hypopituitarism. Associated causes of hypopituitarism are pituitary tumors, Sheehan syndrome, pituitary apoplexy, infiltrative diseases, empty Sella syndrome. There is a radiation damage to hypothalamic-pituitary-adrenal axis (HPA) in Iatrogenic Hypopituitarism.
Growth Hormone Abnormalities
Inherited isolated growth hormone deficiency is differentiated into 3 types i.e. type IA, type IB, type II, and type III on the basis of mutations caused in different genes. Growth hormone insensitivity, also known as Laron dwarfism, is a disorder characterized by short stature due to extreme resistance to GH. Acromegaly is also discussed. Special testing for growth hormone includes GH deficiency, which is a provocative test, and GH excess, which is an oral glucose tolerance test (OGTT).
Etiological factors are hormonal, environmental, and genetic factors. Clinical feature of pituitary adenomas follows loss of central vision, oculomotor palsies, hyperphagia. Hyperprolactinemia is the most common endocrinopathy and occurs in lateral or posterior parts of gland. Pathologically, lactotroph adenomas are chromophobic. For the treatment of hyperprolactinemia, dopamine agonists and inhibition of PRL secretion is used to cure microadenomas. However, surgery and radiation therapy are followed for macroadenomas.
Types of Pituitary Adenomas
Somatotroph adenomas occurs due to excess GH secretion. Pathologically, densely granulated adenomas are acidophilic cells with granular cytoplasm and diffuse growth pattern. Sparsely granulated adenomas are small chromophobe cells. Treatment can be carried out through transsphenoidal hypophysectomy, radiation therapy, or long-acting analog of somatostatin. Corticotrope adenomas, Gonadotroph adenomas, Thyrotrope adenomas, and Nonfunctional pituitary adenomas are also discussed in succession in this section.
Posterior Pituitary Disorders
Central diabetes insipidus is a lack of the hormone vasopressin that causes excessive production of very dilute urine. Dr. Ammar Hassan elaborates the causes of central diabetes insipidus. Nephrogenic diabetes insipidus is caused by problems related to a hormone called antidiuretic hormone or ADH. In this condition, the hormone is produced normally but kidneys are unable to sense its production. Craniopharyngiomas are caused due to central diabetes insipidus, and trauma and hypophysectomy. There is a localized hemorrhage or infarction.