Potassium Disorders Flashcards
List some ECG features of Hyperkalaemia
- Small P waves
- Tall tented T waves
- Broad QRS complexes
List some causes of hyperkalaemia?
- Reduced renal excretion
- Redistribution (metabolic acidosis)
-Increased intake
What can cause reduced renal excretion of potassium, leading to hyperkalaemia?
- Renal failure
- ACE inhibitors
- Potassium sparing diuretics
- Addison’s disease
What can cause increased intake of potassium, leading to hyperkalaemia?
- Increased intake (Unlikely unless renal excretion impaired)
- Over-supplementation in IV fluids or TPN
- Blood transfusion
What can cause pseudohyperkalaemia?
- Haemolysis
- Delayed centrifugation
- Sample contamination (eg EDTA)
- Increased platelet or white cell count
What are the main treatment methods for emergency treatment of hyperkalaemia?
-Calcium chloride (Protect heart)
-Moving potassium into cells
(Insulin, salbutamol)
-Removing potassium from body
What are some signs of hypokalaemia?
- Muscle weakness
- Muscle pain
- ECG changes
What are some ECG changed seen in hypokalaemia?
- Flattened T waves
- U waves
- Smaller QRS waves
- Prolonged QT interval
What may cause hypokalaemia due to gastrointetinal loss?
- Vomiting
- Diarrhoea
- Laxative abuse
- Villous adenoma
- Intestinal fistula
What may cause hypokalaemia due to renal loss?
- Diuretics
- Magneisum depletion
- Cushing’s Syndrome
- Conn’s syndrome
- Bartter’s or Gitelman’s syndrome (Inherited conditions)
- Renal tubular acidosis
What is increased in cushing’s syndrome?
Excess cortisol
What is increased in conn’s syndrome?
Excess aldesterone
What may cause hypokalaemia due to redistribution?
Metabolic alkalosis
What is the management of hypokalaemia?
- Correct underlying cause
- Oral replacement
- Intravenous replacement if severe
- Do not give IV potassium faster than 20 mmol/hr
- Use ECG monitoring if giving faster than 10 mmol/hr
