welcome back to learn with Med nuggets in this video we will be talking about syndrome of inappropriate antidiuretic hormone secretion also known as siadh ADH also known as vasopressin is a hormone that is made in the hypothalamus it is then stored and released by the posterior pituitary gland ADH is a hormone that regulates the water balance in our body by causing reabsorption of water in the distal convoluted tubule and collecting duct cells in kidney abnormally high levels of ADH can lead to siadh while deficiency or insensitivity to the action of ADH can cause diabetes insipidus in this video we will look at what siadh is the pathophysiology the etiology diagnosis treatment and some important clinical points of siadh scadh is a condition in which your body makes too much ADH these courses increased water retention in the body which can lead to two things number one it dilutes other solutes floating around in our body like sodium number two the massive volume expansion caused by high levels of ADH inhibits the release of a hormone called aldosterone and stimulates the release of two hormones called ANP and BNP aldosterone is a hormone that causes sodium retention and hydrogen ion excretion as a result of the inhibition of aldosterone more sodium ions will be excreted via urine A and P and BNP are two hormones released by your Atria and ventricles when it stretches or dilates due to volume overload A and P and PNP as the names suggest are natural uretic peptides natural uretic means sodium in urine these hormones increase sodium and water excretion remember wherever sodium goes water follows this results in a eurolemic hyponatremia so what causes this mess in our body SI ADH happens when ADH is produced outside the pituitary gland in places where it's not supposed to be made like in the lungs it can also be caused by CNS disorders trauma and by certain drugs or medications like ssris carbamazepine and cyclophosphamide an easy way to remember the causes of siadh for your board exams or med school exams is remember anything to do with the lungs or the brain can cause sidh so why is siadh dangerous because of the low sodium levels very low sodium levels can cause cerebral edema which can cause symptoms like headaches confusion hallucinations coma and even death ADH is diagnosed by Labs a low serum sodium level a serum osmolarity of less than 275 a urine osmolality of more than 100 and a urine sodium of more than 40 in the background of normal renal adrenal and thyroid function is diagnostic of siadh when treating siadh first treat the underlying cause for example if siadh is due to a drug stop the drug restrict fluid intake you can turn to drugs like Loop Diuretics to treat volume overload dermiclocycline a drug that inhibits ADH and web Tans like talbaptan which are ADH receptor antagonists if initial measures fail in patients with acute and severely symptomatic hyponatremia immediate use of hypotonic saline can prevent serious neurologic complications like seizures altered mental status cerebral edema and brain herniation however for patients with chronic hyponatremia you should be careful when using hypotonic saline to correct sodium levels as rapid correction can lead to osmotic demyelination syndrome which can cause coma and paralysis of all four limbs to avoid this correct the sodium slowly at a rate of about 8 m EQ per liter per day thank you for listening have a great day