Electrolyte Imbalances Flashcards
Hyperkalaemia
high serum K+
main complication is cardiac arrhythmias such as ventricular fibrillation
causes of hyperkalaemia
Acute kidney injury Chronic kidney disease Rhabdomyolysis Adrenal insufficiency Tumour lysis syndrome
Aldosterone antagonists (spironolactone and eplerenone) ACE inhibitors Angiotensin II receptor blockers NSAIDs Potassium supplements
investigations for K+
U&E’s
Creatinine, Urea, eGFR
Haemolysis (break down of RBC) can cause a falsely elevated potassium
ECG
tall tented T waves
flattening / absence of p waves
broad QRS complex
treatment of hyperkalaemia
insulin (actrapid 10 units) and dextrose infusion (50mls of 50%)
IV calcium gluconate
insulin and dextrose drives carbohydrates into the cells and will take K+ with them (which will reduce the blood potassium)
calcium gluconate- stabilises the cardiac muscle. reduces the risk of arrhythmia
alternative: Nebulised salbutamol temporarily drives potassium into cells. IV fluids can be used to increase urine output, which encourages potassium loss from the kidneys (but don’t fluid overload patients with renal failure). Oral calcium resonium draws potassium out of the gut and into the stools. It works slowly and is suitable for milder cases of hyperkalaemia. Sodium bicarbonate (IV or oral) may be considered on the advice of a renal specialist in acidotic patients with renal failure. It drives potassium into cells as the acidosis is corrected. Dialysis may be required in severe or persistent cases associated with renal failure.
when do you need to treat hyperkalaemia?
<6mmol/L but otherwise stable renal function= do not need urgent tx, require a chnage in diet / meds
> 6mmol/L and ECG changes need urgent tx
> 6.6mmol/L and regardless of ECG need urgent tx
Hypernatraemia causes and symptoms
sodium >155mol/L
conn's cushing's dehydration diabetes insipidus (cranial / nephrogenic) iatrogenic
symptoms:
thirst, drowsy, dehydrated, agitated, confusion
hypernatraemia treatment
rehydrate with IV fluids- Hartmann’s (avoid saline)
Hyponatramia causes
SIADH
<130-135
125-130
<125 (severe, seizure)
types of hyponatraemia
hypovolemic hyponatraemia: dehydration, diuretics, GI losses (fluid status)
hypervolemic hyponatraemia (dilutional)
too much ADH / vasopressors
heart / kidney / liver failure
(this dilutes the sodium)
give diuretics to get rid of the fluid but be cautious to not cause hypovolemia. loop diuretics.
euvolemic hyponatraemia SIADH mainly drug related (ACEi, ARB) early addisons hypothyroidism
hyponatraemia symptoms
sunken eyes dry mucus membrans hypotension low urine output capillary refill >3s thirsty skin turogr
hyperkalaemia
K+ >5.5mmol/L
risk of arrhythmias (ECG- tall tented T waves)
can be due to inadequate excretion
- potassium sparing (spironolactone)
- chronic renal failure
- ACEi, losartan= reduce K+ excretedon
or addition of K+
- diet
- meds
- iatrogenic fluids
symptoms:
usually an incidental finding
hyperkalaemia treatment
calcium gluconate and insulin
*this stabilises the heart membrane (cardio protective)
10mls of 10% calcium glucagon over 10 mins
insulin transports the K+ back into the cells
(actrapid)
10% dextrose in 500mls to prevent a drop in blood sugar levels
*can give salbutamol nebuliser whilst preparing
hypokalaemia
medication = loose K+
diuretics, loop diuretics, diarrhoea, vomiting
cushing’s disease
conn’s
refeeding syndrome (starvation- body has adapted to anabolic and now fed= catabolic and uses up a lot of electrolytes)
causes:
- Barters?
- Gittlemen? thiazie
hypokalaemia
K+ supplementation SenoKay KCl (IV replacement)
hypomagnesaemia
can cause arrhythmias
check K+, ca2+ aswell
severe hypomagnesemia can cause long QT (torsades de points)
causes: D and V malnourishment alcohol anorexia renal tubular acidosis PPI's
treatment: shock - treat like VF then give IV Mg2+
