Endocrine Patho.pdf

Endocrine Pathophysiology Mechanisms of Hormonal Alterations Too Much or Too Little Hormone 1. Failure of feedback systems 2. Dysfunction of an endocrine gland 3. Altered hormone inactivation or degradation 4. Ectopic hormone release 5. Target cell dysfunction Disease of the Posterior Pituitary Synd...

Endocrine Pathophysiology Mechanisms of Hormonal Alterations Too Much or Too Little Hormone 1. Failure of feedback systems 2. Dysfunction of an endocrine gland 3. Altered hormone inactivation or degradation 4. Ectopic hormone release 5. Target cell dysfunction Disease of the Posterior Pituitary Syndrome of inappropriate antidiuretic hormone (SIADH) secretion ○ Levels of antidiuretic hormone (ADH) are abnormally high. ○ Ectopic secretion of ADH is the most common cause; is also common after surgery and some cancers. ○ Water retention – action of ADH on renal collecting ducts increases their permeability to water, thus increasing water reabsorption by the kidneys. ○ For diagnosis, normal renal, adrenal, and thyroid function must exist. ○ Nephrogenic form – excess free water ○ Characterized by euvolemic hypotonic (dilutional) hyponatremia Volume status – euvolemia Total body water – increased Total body sodium – unchanged Extracellular fluid – increased Edema – absent ○ Characterized by euvolemic, hypotonic (dilutional) hyponatremia Hyponatremia (