Syndrome Of Inappropriate Antidiuretic Hormone
Is a condition that results from failure in the negative feedback mechanism that regulates inhibition and secretion of ADH. It produces excess ADH, resulting hypothermia and hypoosmolality of serum. The kidneys respond by reabsorbing water in the tubules and excreting sodium; thus the patient becomes severely water intoxicated. SIADH is most commonly caused by ectopic production of ADH by malignant tumors. It can be result of CNS disorders, such as Guillain-Barre syndrome, meningitis, brain tumors, and head trauma. Pulmonary-related conditions, such as pneumonia, and positive pressure ventilation can cause SIADH. Pharmacologic agents such as general anesthetics, thiazine diuretics, oral hypoglycemics, chemotherapeutic agents, and analgesics are also associated with SIADH release.