HYPERKALEMIA

Question 1

what is hyperkalemia ?

Answer 1

plasma potassium in excess of ≥ 5.5 mmol/L

Question 2

classification of hyperkalemia

Answer 2

Mild – 5.5-5.9 mmol/L

Moderate – 6.0-6.4 mmol/L

Severe – >6.5 mmol/L

Question 3

etiology of hyperkalemia ?

Answer 3

renal
acute kidney injury
chronic kidney disease
hyperkalaemia renal tubular acidosis

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iatrogenic 
ACE inhibitors 
ARB 
potassium sparing diuretics 
renin inhibitor 
NSAIDS and cox 2 inhibitors 
digoxin in toxicity 
beta blockers 
Heparin – unfractionated and LMWH

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blood transfusion

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trauma and burns - significant realise of potassium from cels

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diabetic ketoacidosis
potassium shifts from intracellular to extracellular due to lack of insulin

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addison disease

aldosterone promotes excretion of potassium by the kidney

Addison’s disease, the adrenal glands are unable to produce adequate levels of aldosterone which results in reduced renal excretion of potassium.

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pseudohyperkalemia

Haemolysis (e.g. prolonged tourniquet time, prolonged sample transport time, use of incorrect blood bottles)
Blood sample being taken from a limb receiving IV fluids containing potassium
Leukocytosis and thrombocytosis

Question 4

clinical feature of hyperkalemia ?

Answer 4

Cardiac arrhythmias
atrioventricular block -bradycardia
ventricular fibrillation

Muscle weakness, paralysis, paresthesia

↓ Deep tendon reflexes

Nausea, vomiting, diarrhea

Question 5

what re the investigations of hyperkalemia ?

Answer 5

Urea and elctrolyres
always ask for repeat UE sample - atleast TWO SEPRATE SAMPLES ARE NEEDED to diagnose hyperkalemia - because hyperkalaemia can happen due to hemolysis

Serum electrolytes
Na+: normal or can be ↓ in adrenal insufficienc
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ECG

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renal function test

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FBC - rule out haemolysis 
or leukocytosis 
decreased haptoglobulin 
increased lactate dehydrogenase 
increased unconjugated bilirubin 

peripheral blood smear

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DKA

glucose < 33 mol/l
Bicarbonate < < 18 mEq/L (< 18 mmol/L)
Elevated anion gap

Serum beta-hydroxybutyrate elevated

ABG - blood PH reduced

urine analysis - urine dipstick test detect acetoacetate and acetone but not beta-hydroxybutyrate.
ketonuria/ketonemia
glucosurea

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hyperkalaemic renal tubular acidosis
ANG

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Serum cortisol should be performed to rule out Addison’s disease (low serum cortisol is found in Addison’s).

Question 6

what’s the management fo hyperkalemia ?

Answer 6

call for help

A-E

ECG is essential 
ECG changes in hyperkalaemia 
1) peaked tall T waves *
2) Wide QRS complexes *
3) Prolonged PR interval *
4) Flattened indiscernible P waves
5) AV block
6) Bradycardia

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always ask for repeat UE sample - atleast TWO SEPRATE SAMPLES ARE NEEDED to diagnose hyperkalemia - because hyperkalaemia can happen due to hemolysis

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Urgency by which hyperkalemia needs to be treated is determined by the level of potassium and the presence/absence of associated ECG changes

potassium level of ≥6.5 mmol/L and/or a patient with hyperkalaemia associated ECG changes requires URGENT treatment

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Prevent further accumulation of potassium

1) Stopping any intravenous fluids containing potassium
2) Suspending any medications that have the potential to increase serum potassium
3) Suspending any supplements containing potassium

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STABALISE THE CARDIAC MEMEBRANE

Administer intravenous CALCIUM GLUCONATE - (10ml 10 percent)
if there are hyperkalaemia associated ECG changes present

Further doses may be required if ECG changes persist (you would expect ECG changes to begin to improve within 1-3 minutes from the administration of calcium gluconate - SO DO ECG AFTER 1-3 min

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SHIFT POTASSIUM INTRACELLULARLY

Insulin-dextrose (10 units of act rapid and 50ml of 50 percent of dextrose) infusion
fast-acting insulin

Salbutamol: often used as adjuvant therapy for hyperkalaemia
(nebuliser or IV)

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REMOVE POTASSIUM FROM THE BODY

Calcium polystyrene sulfonate resin (Calcium resonium) can be used to remove potassium via the gastrointestinal tract.
(orally or per rectum)
give a laxative - so increase the output of potassium - it will tae hours to have a acute effect

Haemodialysis is an invasive treatment reserved as a last resort for resistant hyperkalaemia - QUICKETS POSSIBLE WAY