Sandbox:Vindhya

• Na<135mmol/litre
• decreased effective serum osmolality<275mosm/kg
• urine osmolality>100mosm/kg
• presence of underlying disorders;CNS,pulmonary,malignancies,medications
• normal adrenal and thyroid function
• urine Na concentration>40mmol/l,unless taking diuretics,(or) on a severe salt restriction.
• absence of edematous diseases(such as heart failure,nephrotic syndrome, liver cirrhosis)|SIADH

Disease SIADH	Features	SIADH is a disease categorized as hypo-osmolar hyponatremia; small amount of volume expansion is caused by excess of renal water reabsorption through inappropriate antidiuretic hormone (ADH) secretion. In patients with SIADH there is too much water in the blood,this leads to low sodium in the body. Hyponatremia is the most common manifestation. The symptoms are based on level of sodium.(hyponatremia: sodium level below 135meq/l). When symptoms do occur, they may include any of the following: Headache, altered mental status, frequent falls, neurologic manifestations such as lethargy and confusion. In severe cases , seizures and coma may result.	Investigative findings
function urine Na concentration>40mmol/l,unless taking diuretics,(or) on a severe salt restriction. absence of edematous diseases(such as heart failure,nephrotic syndrome, liver cirrhosis)
Cerebral salt wasting	Cerebral salt wasting is defined as the renal loss of sodium during intracranial disease leading to hyponatremia and a decrease in extracellular fluid volume.
Adrenal insufficiency	Adrenal insufficiency ranges from mild nonspecific symptoms to life-threatening shock condition. An important distinction in these patients is the presence of mineralocorticoid deficiency. Those with secondary or tertiary adrenal insufficiency will typically have preserved mineralocorticoid function due to the separate feedback systems. Adrenal insufficency can be primary, secondary or tertiary. Common causes of primary adrenal insufficiency: Autoimmune Iatrogenic Drugs Others- adrenal hemorrhage, cancer, infection. congenital. Secondary adrenal insufficiency refers to decreased adrenocorticotropic hormone (ACTH) stimulation of the adrenal cortex and therefore does not affect aldosterone levels. Traumatic brain injury (TBI) and panhypopituitarism are common causes. Tertiary adrenal insufficiency refers to decreased hypothalamic stimulation of the pituitary to secrete ACTH. Exogenous steroid administration is the most common cause of tertiary adrenal insufficiency.
Hypopituitarism:	Hypopituitarism is defined as the partial or complete loss of anterior pituitary function that can result from acquired or congenital causes. Etiology is as follows: Pituitary tumors Sellar tumors Head trauma Infection empty sella infiltration Idiopathic congenital
Hypothyroidism
Psychogenic polydipsia

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2]

Differential diagnosis

Agents and means used in the treatment of SIADH.

Indirect modalities:

• treatment of underlying pathology
• salt restriction
• Hyper-tonic saline
• Loop diuretics
• Urea
• Demecloclycline, lithium
• Hemodialysis, CVVH(continuous veno-venous hemofiltration), SLED(slow, low-efficiency daily dialysis).

Direct modalities:

"Vaptan drugs": block action of vasopressin at it's receptors,(V1A,V1B,V2)

Prognosis:Patients with SIADH have different characteristics and a different prognosis according to SIADH etiology. Serum sodium concentration at short-term follow-up is predictive of long-term survival. These findings might have diagnostic and treatment-related implications.