Diseases of the Endocrine Glands

1. Diseases of the Endocrine Glands

7. Major Determinants of Disease Many endocrine organs are controlled by the pituitary gland Nonendocrine conditions can cause excessive production of endocrine hormones Overstimulation of target organs by pituitary hormones leads to enlargement of the target organs & overproduction of its hormones Overproduction of endocrine hormones accounts for most of the manifestations of endocrine disease Overproduction of hormones may be caused by hyperplasia or neoplasia of endocrine glands Underproduction of hormones is usually caused by disease of the target organ, rather than to failure of hormone stimulation Pituitary tumors may cause symptoms by pressing on adjacent structures (mass effect), not necessarily by producing hormones

8. Pituitary Diseases Most often anterior lobe Mass such as a neoplasm is most common disease Masses have 2 consequences besides hormone production mass effect pressure on nearby structures intracranial pressure stalk effect interference with hypothalamic inhibition of prolactin secretion Most common mass is an adenoma

9. Hyperpituitarism Mostly from adenomas usually single cell type most are functioning secrete single hormone more common in men usually discrete nodules excessive hormone production, mass effect, stalk effect

11. Prolactinoma Most common functioning adenoma Causes lactation amenorrhea infertility decreased sexual drive impotence Confirmed by high levels of prolactin Caused by high-dose estrogen therapy pregnancy renal failure thyroid gland failure hypothalamic lesions

12. Growth Hormone Adenoma 2nd most common functioning adenoma Subtle manifestations initially Causes gigantism acromegaly

16. Hypopituitarism About 75% of gland must be destroyed to become symptomatic Most common causes of failure are mass effect infarction surgical or radiotherapeutic destruction Target organs atrophy

17. Sheehan Syndrome Infarction of pituitary in pregnancy enlarges mostly due to prolactin secreting cells not enough blood supply

18. Diabetes Insipidus High output of very dilute urine Destruction of pituitary or conditions affecting the hypothalamus head trauma surgery neoplasm infarction inflammation Genetic defects of ADH synthesis Renal defect

19. Hyperthyroidism Increased metabolic rate (thyrotoxicosis) Causes overmedication in thyroid gland failure increased hormone due to thyroid gland diseases � primary increased hormone due to TSH - secondary

20. Graves Disease 80-90% of all hyperthyroidism One of most common autoimmune diseases in US Mostly women Antibody that acts like TSH Gland is diffusely enlarged & smooth

24. Hypothyroidism Usually primary Could by due to lack of dietary iodine