SIADH

• ADH increases water reabsorption
• water reabsorption increases blood volume and decreases serum osmolarity
• SIADH is over secretion of ADH leading to more ADH in the blood, resulting in more water water retained-this increases blood volume(increase GFR) and decreases serum osmolarity
• people with SIADH have high amounts of sodium in the urine
• causes of SIADH include: 1)trauma to the brain or pituitary, 2)CNS disorder or infection such as meningitis, 3)malignancy-ectopic production of ADH such as ADH produced from lung cancer or pancreatic cancer, 4)non-neoplastic/non-malignant -ADH from respiratory infections-pneumonia, 5)stroke
• SIADH is characterized by hyponatremia(low sodium levels in blood)
• clinically, patients with SIADH are euvolemic(normal blood volume or fluids in the body)
• symptoms and signs of SIADH are related to low sodium levels in the blood. so patients have hyponatremia.
• 120 mmol/L or Less is a sign of severe hyponatremia
• in acute hyponatremia, hyponatremia occured for less than 48 hours. signs: cerebral edema,neurogenic pulmonary edema,seizures, coma
• there is no cerebral edema in chronic hyponatremia. Chronic hyponatremia is characterized by non-specific symptoms like: headache,nausea,vomiting and seizures.
• medications that can cause increase in ADH production include: chemotherapy,antidepressants,recreational drugs-cocaine,diuretics,inhibitors-ACE inhibitors,Sulfonylurea,hormone-desmopressin. "CARDISH"
• MEDICINE treatment of SIADH include: 1)fluid overload-give furosemide,oral,40mg,12hourly. 2)absence of fluid overload-give sodium chloride IV infusion.