siadh
Table of Contents
syndrome of inappropriate ADH secretion (SIADH)
introduction
- SIADH is increased ADH secretion despite normal or elevated plasma volume which causes reduced renal water excretion and resulting hyponatraemia and hypo-osmolality
Diagnostic criteria
- Barrter and Schwartz:
- decreased serum osmolality (<275 mOsm/kg)
- increased urine osmolality (>100 mOsm/kg)
- euvolaemia
- increased urine sodium (>20 mmol/L)
- no other cause for hyponatraemia
aetiology
central nervous system causes
- brain tumours
- encephalopathies
- brain abscess
- hydrocephalus
- etc…
drug-induced
increased secretion of ADH
- nicotine
- histamine
- acetylcholine
- bromocryptine
- antineoplastic agents
- chlorpropamide
- halothane
- nitrous oxide
increased effects of ADH
- vasopressin analogs
other drugs include
pulmonary causes
- most pulmonary conditions can cause it
paraneoplastic
- Ewing sarcoma
- nasopharyngeal tumours
- thymoma
- adrenocortical carcinoma
- olfactory neuroblastoma
ectopic ADH secretion
- carcinoid tumours
other causes
- exercise-induced hyponatraemia
- giant cell arteritis
- idiopathic
Mx
siadh.txt · Last modified: 2021/06/20 06:53 by gary1