Syndrome of Inappropriate AntiDiuretic Hormone
Syndrome of Inappropriate AntiDiuretic Hormone (SIADH) is TOO MUCH ADH. You are storing all your water and become SOAKED INSIDE. On the NCLEX, you may see a client with a pituitary tumor who develops SIADH. Due to the tumor, the pituitary gland is releasing ADH in excess. The best position for this client is  bed flat which enhances venous return to the heart and increases the left arterial filling pressure, thereby reducing the release of antidiuretic hormone. Bed should not be elevated more than 10 degrees.
HOB flat or < 10 degrees in pituitary tumors. NCLEX alertÂ
Causes
- Brain causes: injury, surgery, tumors, infection, TCA’s, nicotine
- small cell Lung cancer patients are at the highest risk
Symptoms
Labs
- Hyponatremia (retaining fluid so sodium dilutes)
- Low Osmolality (Dilution due to retaining fluid)
- Urine with ↑ Specific Gravity (Concentrated)
Treatment
- Seizures precautions (watch for headache and confusion).
- Restrict fluids
- Diuretics (furosemide)
- Vasopressin (ADH) antagonists (Demeclocycline and Conivaptan or vaptans)
- Monitor Weight
The clearer the urine, the lowest the specific gravity. DI’s urine has low specific gravity < 1.010. Â
Darker urine has high specific gravity. SIADH retains all the water and pees concentrated with Specific gravity > 1.030
DI makes urine with low osmolality and since it is dry inside, serum osmolality is high
SIADH makes urine with high osmolality (concentrated) and since it is soaked inside, serum osmolality is low.