Hyperkalaemia

Question 1

An 85 year old male has a history of congestive cardiac failure with previous admissions for pulmonary oedema and biventricular failure. His serum potassium is 6.3mmol/L. His medications include frusemide, candesartan, spironolactone, bisoprolol and aspirin. How would you manage this situation?

Answer 1

Impression
Hyperkalaemia in the setting of heart failure and multiple medications. Whilst mildly elevated, I am concerned about the risk of cardiac arrhythmia’s and sudden death and thus want to manage this emergently, calling for senior input. In this patient, I am concerned about concurrent AKI in the setting of being prescribed the triple whammy.

DDx

• Reduced excretion: renal disease, AKI
• Increased cell turnover: rhabdo, TLS, burns
• Deranged distribution: metabolic acidosis
• Dehydration
• Medications: Triple whammy, other potassium-elevating meds (MRA, ß-Blocker, etc)
• lab error/haemolysed blood sample

Goals

• Identify underlying cause of hyperkalaemia with targeted Hx/Ex/Ix, prevent complications of HyperK
• Optimise heart failure management, undertake medications review/revision

Question 2

Hyperkalaemia - Assessment

Answer 2

Assessment

• call for senior advice (registrar), liaise with treating team regarding ceasing/witholding certain medications
• assess for any emergent instability/changes
• Cease Triple whammy and other K-elevating medications

A - patent, maintaining
B - RR/SP02 monitoring. supplemental as required
C - IV access; serial ECG monitoring for changes associated with hyperKinitial bloods (VBG, FBC, etc depending on what’s already ordered, UEC). Cease drugs that are increasing his K level (spironolactone, ?bisoprolol on advice of cardio)
o IV calcium gluconate
o IV sodium bicarbonate/insulin-dex (not salbutamol given heart disease history)
o PR resonium, keep frusemide for diuresis and increased excretion
o consider haemodialysis
D - GCS

• conduct concurrent Hx and Examination

Question 3

Hyperkalaemia - History

Answer 3

History

• PC: details of presentation, progression, timing
• sx: muscle weakness, palpitations, altered mental state
• review patient notes for previous blood test results, reason for admission, treatment plan and ongoing management
• Other: features of AKI (reduced UO, oedema, fatigue); CCF (coughing, swelling, PND, orthopnoea, etc)
• Medications: any recent changes?

Question 4

Hyperkalaemia - Examination

Answer 4

Examination

• General appearance + vitals
• Cardioresp for worsening features of APO and biventricular failure (JVP, peripheral oedema, lung fields
• fluid status assessment (dry or overfilled)

Question 5

Hyperkalaemia - Investigations

Answer 5

Investigations
Key/Diagnostic
- VBG/UEC - serum potassium
- ECG: Bizarre QRS, loss of p wave, peaked T wave, PR shortening, Sine wave

Further imaging based on other aspects of presentation;
- CXR, ECHO, other bloods.

Question 6

Hyperkalaemia - Management

Answer 6

Management

• initially as per A to E assessment for acute stabilisation
• renal and cardiac consult for management pathway

Ongoing

• Further investigation for underlying cause
• Medications review, attempt to cease some agents associated with hyperkalaemia, STOP triple whammy immediately. Cease spironolactone, consider ceasing the ARB
• Optimise HF treatment non pharmacologically and pharmacologically (ARNI, etc)
• Appropriate cardiac review/consult
• Daily fluid balance and weights
• IV fluids if over-diuresed and volume depleted

Other

• Low K diet (stop bananas + prunes)
• Potassium-wasting diuretics (thiazide/loop diuretics)