SIADH Flashcards
Where is ADH secreted from
posterior pituitary
what does ADH do
stimulates water reabsorption from the collecting ducts
effects of increased ADH on the urine
increased urine concentration
- more water is reabsorbed
effects of decreased ADH on the urine
decreased urine concentration
- less water is reabsorbed
what cancer commonly causes SIADH
small cell lung cancer
what drugs can cause SIADH
SSRI- fluoxetine
carbamazepine
diuretics
how is sodium affected in SIADH
hyponatraemia
- euvolaemic hyponatraemia
what is urine and serum osmolality like in SIADH
high urine osmolality
low serum osmolality
symptoms of SIADH
nausea dizziness muscle aches + cramps confusion fatigue
clinical picture SIADH
euvolaemia
hyponatraemia
high urine osmolality
high urine sodium
what is the risk with rapid correction of hyponatraemia
osmotic demyelination syndrome (central pontine myelinosis)
speech disturbance, limb paralysis, swollowing difficulty, movement disorders two days after correction of hyponatraemia suggests what?
osmotic demyelination syndrome / central pontine myelinosis
treatment options for SIADH
remove causative drugs
fluid restriction (may be enough without needing to administer drugs)
Tolvaptan - ADH receptor blocker
demeclocycline - tetracycline antibiotic that inhibits ADH
