A low sodium level or hyponatremia is a major complication of SIADH and is responsible for many of the symptoms of SIADH. Early symptoms may be mild and include cramping, nausea, and vomiting. In severe cases, SIADH can cause confusion, seizures, and coma.
Is sodium high in SIADH?
SIADH often leads to low levels of sodium in the blood (hyponatremia), high urine osmolality and excessive sodium in the urine, and low serum osmolality. It is the most common cause of hyponatremia.
Is urine output high or low in SIADH?
In SIADH, the body is unable to suppress the secretion of ADH, leading to impaired water excretion and reduced urine output. Normally, when water is ingested, serum tonicity and osmolality decrease and ADH is suppressed, resulting in output of a dilute (less concentrated) urine. This pathway is impaired in SIADH.
Which signs and symptoms are consistent with SIADH?
- Nausea or vomiting.
- Cramps or tremors.
- Depressed mood,memory impairment.
- Irritability.
- Personality changes, such as combativeness, confusion, and hallucinations.
- Seizures.
- Stupor or coma.
Is ADH high or low in SIADH?
In patients with SIADH, levels of ADH are high even in the presence of decreased plasma osmolality and/or hyponatremia. Excess water absorption keeps the blood volume high or normal.