Potassium Regulation Flashcards
What are the two most common causes of hypokalaemia? (2)
Diuretics Hyperaldosteronism (Conn's)
Define hypokalaemia. (1)
<3.5 mmol/L
Name 5 causes of hypokalaemia. (5)
- Increased renal excretion: diuretics, hypomagnesaemia, increased aldosterone secretion (LF, HF, nephrotic, Cushings, Conn’s), exogenous mineralocorticoid, renal tubular acidosis/damage.
- GI losses: prolonged vomiting, profuse diarrhoea, ileostomies
- Redistribution into cells: alkalosis, b agonists, insulin
- reduced intake: severe dietary deficiency, inadequate replacement with IV fluids
What clinical features may accompany hypokalaemia? (2)
Usually Symptomatic.
May have muscle weakness if severe. (Also increased risk of arrhythmias)
Which drug level should be checked if patient is found to be hypokalaemic? (1)
Digoxin
What are the ecg changes you may see in severe hypokalaemia? (2)
U waves
Small T
Long PR
Long QT
Before correcting hypokalaemia, which other electrolyte imbalance should be normalised first? (1)
Hypomagnesaemia
Name 4 causes of hyperkalaemia. (4)
Decreased excretion: AKI, drugs (ACEi, potassium sparing diuretics, NSAIDs, ciclosporin, heparin), Addison’s
Redistribution: DKA, metabolic acidosis, tissue necrosis
Increased intake: potassium chloride, salt substitute, transfusion of stored blood.
Describe the progression of ECG changes seen in hyperkalaemia. (3)
Tall tented T waves
Flattened P waves
Widened QRS
Mild hyperkalaemia can be treated with dietary potassium restriction, restriction of causative drugs and loop diuretic to increase excretion.
When is hyperkalaemia a medical emergency requiring immediate action? (2)
If severe (>6.5 mmol/L) or >6.0 mmol/L with ECG changes
Describe the emergency management of hyperkalaemia. (3)
Calcium gluconate: 10ml of 10%, repeat after 5 mins if ECG persists
Insulin/glucose: 10u with 50ml of 50%. Effects last 1-2 hours.
Salbutamol 10mg
Calcium resonium: to bind dietary potassium.
Stop causative drugs, monitor blood glucose and potassium.
