Hyperkalaemia

Question 1

Define Hyperkalaemia

Answer 1

Hyperkalaemia is when serum K+ level > 5.5 mmol/L

Question 2

Mild hyperkalaemia range

Answer 2

5.5 - 6.0 mmol/L

Question 3

Moderate hyperkalaemia range

Answer 3

6.0 - 6.5 mmol/L

Question 4

Severe hyperkalaemia

Answer 4

• > 6.5 mmol/L

Question 5

Meds that increases K+ in serum

Answer 5

• ACE-i
• ARBs
• Digoxin
• Spironolactone

Question 6

Impaired excretion of potassium

Answer 6

AKI
CKD
Medications (ACE-i, ARBs, K+ sparing diuretics, NSAIDs, heparin, trimethoprim, ciclosporin)
Type 4 renal tubular acidosis
Hypoadrenalism (e.g. Addison’s disease)

Question 7

Increased cellular release causes of hyperkalaemia

Answer 7

Metabolic acidosis
Hyperglycaemia
Rhabdomyolysis
Tumour lysis syndrome
Packed red blood cell transfusion
Digoxin toxicity
Beta blockers
Severe burns
Hyperkalaemic periodic paralysis

Question 8

Define Pseudohyperkalaemia

Answer 8

An artifactual increase in potassium in the sample tested

Question 9

Pseudohyperkalaemia causes

Answer 9

• the use of small venepuncture needle
• Prolonged tourniquet time
• Difficult venepuncture
• Delayed specimen processing

Question 10

Hyperkalaemia Sx

Answer 10

Palpitations
Fatigue
Chest pain
Shortness of breath
Paralysis

Question 11

Hyperkalaemia clinical signs

Answer 11

Arrhythmias (e.g. bradycardia)
Reduced muscle power +/- flaccid paralysis
Hyporeflexia

Question 12

How do acidosis increase K+ in the serum

Answer 12

Through the exchanges of H+/K+ via the H+/K+ pump

Question 13

Hyperkalaemia Ix

Answer 13

1. VBG - K+ level, acid-base status, lactate level
2. ECG - assoc. conduction abnormalities
3. UEs - K+, Na+, egfr, Cr

Question 14

Hyperkalaemia ECG findings

Answer 14

• Tented T wave
• flattened P waves
• PR prolongation
• broad QRS

Question 15

Hyperkalaemia Medical Mx steps

Answer 15

1. Myocardium stabilisation: 1. IV calcium chloride 10%
   Dose: 5-10ml over 10 minutes
   OR
   IV calcium gluconate 10%
   Dose: 10-20ml over 5-10 minutes
2. K+ shift - drive K+ into the cells: IV insulin + dextrose: 10 unit insulin + 50ml 50% dextrose over 15-30mins
   BM monitoring, 15mins intervals for an hour and then hourly up to 6 hours
   Salbutamol 10-20mg Nebs
   NaHCO3 - for severe metabolic acidosis
3. Potassium elimination: Oral calcium resonium reduces potassium absorption in the GI tract (this is slow and causes constipation)
   Haemodialysis
4. Prevent recurrence

Question 16

Prevent recurrence of hyperkalaemia

Answer 16

• Take a Hx
• Causes of high K+
• Medication use: ACE-I,
• Low K+ diet
• (crystalloid - Plasmolite) K+ concentration is less than pt K+ level therefore creating a K+ gradient for K+ level to shift intracellularly