SIADH

Question 1

Pathophysiology of SIADH?

Answer 1

Osmosis

Question 2

Clinical features of SIADH?

Answer 2

N V irritability
Confusion coma fits (cerebral edema due to low sodium)
< 125 mild symptoms
< 115 serious manifestations

Question 3

Aetiology of SIADH?

Answer 3

Tumours
Almost all lung causes 
All the brain conditions
Sx
Fhx
alchohol withdrawal 
Drugs (carbamazepine,chlorpropamide,cyclophosphamide)

Question 4

Dx of SIADH?

Answer 4

1. dilutional hyponatremia
2. low plasma osmolality with inappropriate urine osmolality > 100 mosm/kg
3. Na excretion > 30 mmol/l
4. N potassium bp adrenal renal and thyroid function

Question 5

Tx?

Answer 5

1. underlying cause
2. Restrictions of fluid intake
3. Demecloyclin 600-1200 mg daily (inhibit ADH in kidney )
4. If severe hypertonic saline

Chronic hyponatremia hv to be corrected slowly (max 10/day) otherwise will cause central pontine myelinolysis (osmotic demyelination) causing quadriplegia