Hyper and hypokalaemia Flashcards
Hyperkalaemia
Greater than 5.5 mmol/l
Causes of hyperkalaemia
Post-operative AKI
Repeated blood transfusions
Drugs:
Potassium-Sparing Diuretics- Spironolactone
ACE inhibitors (or ARBs)
Excessive potassium treatment
Presentation of hyperkalaemia
Normally asymptomatic
Paraesthesia
Muscle weakness
Nausea and vomiting
Palpitations
Investigations
Obs
Fluid status
Routine bloods: U&Es, Ca2+ and PO42-, and Mg2+
Venous blood gas
ECG
Catheterisation -for fluid balance monitoring
ECG for hyperkalaemia
Tall tented T waves
Widened QRS
Decreased PR interval
Flattened P wave
Sine wave
Cardiac complications of hyperkalaemia
Ventricular Fibrillation (VF) or asystole
Management of hyperkalaemia
Stabilisation of the myocardium - calcium gluconate IV
Reduction of serum potassium - Insulin + glucose
- Salbutamol
Reduction of total body potassium
- calcium resonium oral
Hypokalaemia
< 3.5mmol/L
Severity of hypokalaemia
Mild = 3.1 – 3.5mmol/L
Moderate = 2.5 – 3.0mmol/L
Severe = < 2.5mmol/L
Common surgical causes for hypokalaemia
Excess Loss:
- Vomiting
- Diarrhoea
- Fistulae formation
- Laxative abuse
Urinary losses:
- Diuretics (thiazide, loop diuretics, acetazolamide)
Inadequate Intake:
- Malnutrition
- Inadequate intravenous potassium replacement (in nil-by-mouth patients)
Excessive insulin administration
Excessive beta-adrenergic agonist activity
Presentation of hypokalaemia
Asymptomatic
Muscle weakness
Paraesthesia
Ileus or pseudo-obstruction
Hypotonia
Hyporeflexia
Muscle cramps
Tetany
ECG for hypokalaemia
Elongated PR interval
T wave flattening or T wave inversion
Prominent U wave
ST segment depression
Eventually develop into life-threatening arrhythmias such as VT or VF
Mx of hypokalaemia
Treta underlying cause
Replacement:
- oral supplements -SandoK
- IV K+ 40mg
Which additional cation is essential to check for in cases of hypokalaemia?
Magnesium
deficiency exacerbates potassium wasting by increasing potassium secretion
