Hyperkalaemia and Hypokalaemia Flashcards
define Hyperkalaemia and Hypokalaemia
High or low levels of potassium in the blood
what are the causes of hyperkalaemia?
-increased intake of potassium
-decreased excretion of potassium
-potassium shifted to extracellular
-trauma
-burns
what causes Increased intake of potassium?
- IV therapy
-Increased dietary intake
what causes decreased excretion of potassium?
- AKI and CKD
-Drugs (NSAIDs, spironolactone, ACE inhibitors)
-Renal tubular acidosis (T4)
-Addison’s disease
What causes Potassium shifted to extracellular?
- Metabolic acidosis/DKA
-Rhabdomyolysis
describe an ECG with hyperkalaemia
-Absent P waves
-Prolonged PR interval
-Tall, tented T-waves
-Wide QRS complex
-Bradycardia
what is the presentation of hyperkalaemia?
- Muscle weakness and cramps
-Paraesthesia
-Palpitations
-Tachycardia (arrhythmias)
High K+ decreases the action potential, causing easier depolarisation, and leading to arrhythmias.
what is the effect of hyperkalaemia on muscles?
-Smooth muscle cramping
-Skeletal muscle weakness due to over contraction
-Cardiac arrhythmias and arrest
what is the treatment of hyperkalaemia when urgent?
Calcium gluconate to stabilise the cardiac membrane, if there are cardiac problems, then insulin dextrose
what is the treatment of hyperkalaemia when non urgent?
Insulin (+dextrose)
define hypokalaemia
Hypokalaemia ≤ 3.5mmol/L
define emergency hypokalaemia
Emergency Hypokalaemia ≤ 3mmol/L
define hyperkalaemia
Hyperkalaemia ≥ 5mmol/L
define Emergency Hyperkalaemia
Emergency Hyperkalaemia ≥ 6.5mmol/L
what are the causes of hypokalaemia?
-Decreased intake of potassium
-Increased excretion of potassium
-potassium shifted to intracellular
what causes an increase in excretion of potassium?
-Thiazides + loop diuretics
-Renal disease
- GI loss
-Increased aldosterone
what causes potassium to shift to intracellular?
- Insulin
-Salbutamol (+other drugs)
what is the presentation of hypokalaemia?
-Hypotonia
-Hyporeflexia
-Arrhythmias
-Muscle paralysis + rhabdomyolysis
What are the effects of hyperkalaemia?
- insulin deficiency due to affected k+ flow
- acidosis ( H+K+ flow affected)
- beta blocker- inhibit pumping of K+ into the cell
What are the effects of hypokalaemia?
- insulin excess due to affected k+ flow
- alkalosis ( H+K+ flow affected)
- b2 agonist- increase pumping of K+ into the cell
what does an ECG with hypokalaemia have?
Small inverted T waves
Prominent U waves
ST segment depression
what is the effect of hypokalaemia on muscles?
-Smooth muscle constipation
-Skeletal muscle weakness and cramps
-Cardiac arrhythmias and palpitations
what is the treatment of hypokalaemia?
-K+ replacement*
-Aldosterone antagonist
-Treat underlying cause
-Treat other electrolyte deficiencies
