Potassium Flashcards
Potassium
Mainly in Intracellular fluid and 98% in skeletal muscle
Transmission of nerve impulses, maintenance of normal cardiac rhythms, contraction of skeletal and smooth muscle, regulating osmolality of ICF, metabolic processes, stores glycogen in skeletal muscles
Alters cell membrane potential affecting cardiac, skeletal and GI muscle
Affects cardiac conduction system
Serum potassium increases if cell haemolysis
Hydrogen ions move in opposite direction of K+ so if acidotic high K and alkalotic low K
Hypokalaemia
Cause- loss through kidneys (drugs- diuretics/steroids, antibiotics), hyperaldosteronism, GI losses from vomiting, diarrhoea, ileostomy drainage, inadequate intake, alcoholic/anorexia nervosa ( inadequate intake/vomiting), loss of hydrogen ions/alkalosis, excess insulin (promotes intake into skeletal muscle and liver cells), conns disease, barterrs syndrome, during treatment of DKA, liquorice abuse
S&S- ECG changes- inverted T wave, U wave, depressed ST), arrhythmia, digital is toxicity, nausea/vomiting, decreases bowel sounds (slow peristalsis in bowels), ileus, leg cramps, insulin secretion suppressed, suppressed synthesis of glycogen in skeletal muscle and liver, rhabdomyolysis (muscle fibres disintegrate and release myoglobin in urine), polyuria (inability to concentrate urine), resp arrest, confusion, lethargy, depression, irregular pulse, postural hypotension
Diagnose- serum potassium, ECG, arterial blood gas, renal functions
Treat- potassium supplements
Hyperkalaemia
inadequate excretion of potassium, excessive intake, shift potassium from intracellular to extra cellular
Cause- chronic renal failure, adrenal insufficiency, medications (potassium soaring diuretics), acidosis/trauma/chemo/starvation (shift of potassium ions from intracellular space due to excess hydrogen ions entering the cells and displacing potassium), addisons, excessive replacement ,
S&S- bradycardia, heart block, ECG changes (peaked T waves, prolonged PR interval, widening of QRS), ventricular arrhythmia, weakness, paralysis (lower extremities first), GI disturbances, irritability, twitching
Mild- 5-6.5 peaked T waves
Mod- 6.5-8 peaked T waves
Severe >8 absent P waves, widening QRS
Diagnose- ECG, serum electrolytes, ABG
Treat- calcium gluconate IV (temporarily protects heart and muscle from effects), regular insulin and 50g glucose (promote potassium uptake into cells), sodium bicarb for acidosis, sodium polystyrene sulfonate (binds potassium to GI tract), diuretics, dialysis when renal function impaired
