Electrolytes Flashcards
role of Sodium?
aids in maintaining osmotic pressure of serum
symptoms of HYPONATRAEMIA
- nausea
- malaisa
- confusion
- headache
- irritable
- seizures
- reduced consciousness
- coma
hyponatraemia investigations
- serum osmolality
- urine osmolality
- urinary sodium
- TFTs
- random cortisol
what does a high urinary sodium indicate?
sodium is being lost via the kidneys & water is following via osmosis
causes of high urinary sodium (4)
- osmotic diuresis
- excess use of loop diuretics
- renal failure
- addisons disease
causes of normal/low sodium & hypovolemia
- D&V
- fistulae
- burns
- trauma
- CF
Euvolemic & high urinary sodium
SiADH
as sodium is being lost via kidneys
investigation findings in SiADH
- high urine osmolality
- low plasma osmolality
–> concentrated urine because more water is being reabsorbed from the DCT
pathophysiology behind SiADH
inappropriate amount of ADH produced by posterior pituitary gland
5 causes of SiADH
- malignancy (small cell, pancreas, prostate, lymphoma)
- stroke
- head injury
- TB
- pnuemonia
- hypothyroidism
- lupus
drugs causing SiADH (6)
- SSRIs
- ACEi
- anti psychotics e.g. carbmazepine
- opiates
- cytotoxics e.g. cyclophosphamide
- PPIs
causes of Hypervolemic hyponatraemia? and mechanism?
fluid into extracellular space –> depletion of intravascular volume –> ADH release
ADH release causes water reabsorption via kidneys, diluting sodium levels
causes:
- nephrotic syndrome
- CCF
- liver cirrhosis
- renal failure
diuretic & example that lowers sodium level
Loop diuretic e.g. Bendroflumethiazide
life threatening complication of rapid correction of hyponatraemia?
& mechanism
Central pontine myelinolysis
Rapid increase in Na pulls water out of the cells causing destruction of the myelin sheath, especially in pons
symptoms of CPM
- confusion
- dysarthria
- dysphagia
- paralysis
- coma
correction of hyponatraemia rate aim?
9 mmol/L/day