fluid and electrolytes- potassium balance Flashcards
where is >90% of the body’s stores of K+
intracellular, only 2.5 extracellular
what secretes 90-95% of the K+
kidneys. rest is from GI loss
what stimulates the movement of K+ from ECF to ICF
insulin
what promotes K+ excretion in to urine and Na+ reabsorption
aldosterone
what condition promotes movement of K+ from ICF to ECF and what does this result in
metabolic acidosis. hyperkalaemia
signs hypokalaemia
often asymptomatic, neuromuscular, cardiac, renal, metabolic alkalosis
what are the neuromuscular signs hypokalaemia
muscle weakness, cramps, paralysis, constipation, paralytic ileus
what are the cardiac signs of hypokalaemia
ECG changes, arrhythmias, potentiates digoxin toxicity
what are the renal signs of hypokalaemia
polyuria and polydipsia
what are the ECG changes in hypokalaemia
flat T waves, ST wave depression, prolonged QT interval and prominent U waves
what are the causes of hypokalaemia mainly split up into
decreased dietary intake, increased, excretion and transcellular shift
what are the causes of transcellular shift (hypo)
alkalosis, insulin, B agonists (salbutamol), refeeding syndrome, hypokalaemic periodic paralysis
what are the causes of increased secretion (hypo)
renal loss and extra renal loss
what are the causes for renal loss in hypo
diuretics, excess diuresis after AKI, nephrotoxic drugs (gentamicin), mineralocorticoid excess- Conn, Cushings renal tubular acidosis
what are the causes for extra renal loss in hypo
diarrhoea and vomiting, ileostomy
