SIADH Flashcards
what does ADH do
stimulates water reabsorption from collecting ducts in kidney
what is SAIDH
condition where there in inappropriately large amounts of ADH
why might there be too much ADH
posterior pituitary produces too much
coming from elsewhere etc SCLC
SIADH - what happens
excessive water reabsorption which dilutes sodium in blood - hyponatraemia
urine becomes more concentrated - high urine osmolality and high urine sodium
sodium levels
euvolaemic hyponatraemia
urine findings
high osmolality
high sodium
symptoms
headache
fatigue
muscle aches, cramps
confusoin
severe hyponatraemia: seizures, reduced conscoiussness
SIADH causes
post-op major surgery infection: atypical pneumonia, lung abscess head injury medications malignancy eps SCLC meningitis
medications causing SIADH
thiazide diuretics carbamazepine cyclophosphamide antipsychotics SSRIs NSAIDs
diagnosing SIADH
diagnosis of exclusion
other causes of hyponatraemia need to be exlucded e.g. adrenal insuffieicney, CKD, AKI
Mx
establish and treat cause
fluid restriction
tolvaptan
demeclocycline
Mx - aim for sodium change of
less than 10mmol/litre in 24hrs
tolvaptan
ADH receptor blokcers
demeclocycline
tetracyline antibx that inhibits ADH
central pontine myelinolysis
aka osmotic demyelination syndrome
complication of long-term severe hyponatraemia (<120) being treated too quickly (>10mmol/l increase 24hrs)
