Syndrome of inappropriate antidiuretic hormone secretion

Syndrome of inappropriate antidiuretic hormone secretion (SIADH):
It is excessive secretion of endogenous antidiuretic hormone or similar substances by a variety of causes, and occur the obstruction of water excretion, which lead to hyponatremia, water retention and other clinical performance.

Syndrome of inappropriate antidiuretic hormone secretion Causes:
The most common causes is that the tumor tissue autonomy release ADH, accounting for about 80% of SIADH, mainly is caused by oat cell carcinoma of the lung, pancreas, duodenum cancer and lymphoma. Others, such as pneumonia, tuberculosis, impact of the hypothalamus and pituitary function in nerve injury, inflammation and other neurological diseases can also cause excessive secretion of ADH.

Syndrome of inappropriate antidiuretic hormone secretion Symptoms:
In addition to the symptoms of the primary disease, SIADH sign mainly is water retention and hyponatremia. Generally lower than the serum sodium 130mmol / L, when the serum sodium < 120mmol / L, can occur weakness, loss of appetite, nausea and vomiting, lethargy, irritability, and even mental disorders. When the serum sodium <110mmol / L when convulsions, coma or even death. Due to water retention in general no more than 3 to 4 liters, and part of the water transferred to the cells, so in general no edema.

Syndrome of inappropriate antidiuretic hormone secretion Diagnosis:
1. Hyponatremia are generally low-130mmol / L, but increased urinary sodium, often more than 20mmol / L. 2. Urine osmolality higher than plasma osmolality.
3. Without the signs of low blood volume.
4. Strictly limited to the water can correct hyponatremia, low plasma osmolality and high urinary sodium.
5. Can found signs of the primary disease.

Syndrome of inappropriate antidiuretic hormone secretion Treatment:
Patient with mild SIADH, only be treated by taken water restrictions <100ml everyday, then symptoms can be improved, weight loss, serum sodium and osmolality increased, reduced urinary sodium excretion. Patient with severe SIADH, should be treated by slow intravenous infusion for 5% NaCl 200 ~ 300ml, after sime hours gradually enhanced sodium, also can increase water use Furosemide. Application of anti-ADH drugs such as norepinephrine can block the ADH aureomycin on renal tubular reabsorption of water. Lithium salt has a similar function, but greater toxicity. The mainly treatment of SIADH is cause of treatment, to surgical resection for malignant tumors, and radiotherapy chemotherapy.