Question

• Describe the pathophysiology, clinical manifestations, evaluation, and treatment of two diseases of the posterior pituitary–syndrome of inappropriate antidiuretic hormone secretion (SIADH) and diabetes insipidus (DI).

Answer 1

SIADH:

Sundrome of inappropriate antidiurectic hormone recretion [Excessive unsuppresible release a AD11) - Pathophyridogy: Normally there are homeostatic processes in the body which maintain the concentration of body scutes. within a narrow range In SIADH there is an increased ADH (Antidiuretic hormone) secretion which leads to increase in reabsorption in the kidneys .. excess water moves from the distal convelated Aubules and collecting tubules of the nephrons, via activation of aquaporins, the site of the ADH receptors -back into the circulation it leads to hypo osmolality in extracellular fluid space (Elf), including hyponatremia Due to hyposemdality of (ECF) , soluke free water moves from Ecr) to Intracellular fluid (ICF) and it causes cerebral edema a convulsions, coma and death, - clinical manifertations: * Anorexia , nausea. * Decrease * Tremon * lethargy & coma & Death

→ Evaluation: Hyponatremia lie, serum Nat 2135 mnal/h) with concomitant hypo-armolality and high wrine ormolality are the main evaluating features of SIADH. Finding plana Gamolality , Blood glucare, wire asndaling ~ Treatment, & fluid restriction and hypertonic saline commonly weed. - Varoprerring receptor antagonists, called Vaptans are used,

DIABETES INSIPIDUS:

Diabetes gripidus: - Pa Pathophyrology: It is caused by abnormality in the function or levels of antidiuretic hormone also knows of as varopressin. In diabetes impidus, the production or release of ADH is too low to stop the kidneys from Parring dilute wine, which results in an increased dars of water and therefore more thirst. clinical manifertations: * Extreme thirst & Producing large amount of dilute wrine * Frequent need to get up to wrinate during night & weight lors → Evaluation : * water deprivation test * MRI-rean to look for abnormalities in Pituatary gland * Genetic screening Treatment: * Increased water intake hydrochlorothiazide is used * synthetic hormone dermoprenin is given & low salt diet