Hypokalaemia

Question 1

A 44 year old woman is receiving chemotherapy for lymphoma. She has been vomiting frequently and her serum potassium is 3.0 mmol/L. How would you manage her?

Imp/DDx/Goals

Answer 1

Impression
Patient has hypokalaemia based on serum electrolyte findings, most likely related to frequent vomiting. Main concerns are cardiac arrhythmias, muscle paralysis and other electrolyte abnormalities related to severe vomiting.

Goals

• correct electrolyte abnormalities and prevent complications
• treat side effects of chemotherapy, prevent further nausea/vomiting

Question 2

Hypokalaemia 2nd to vomits - Assessment

Answer 2

Assessment:
Risk of diaphragmatic paralysis in hypokalaemia - therefore take ABCDE approach initially
A - patent, maintaining
B - RR, Sats, administer supplemental as required
C - BP, ECG/telemetry, IV access, Bloods, begin electrolyte replacement therapy
D - GCS
E -

• call for senior help

Question 3

Hypokalaemia 2nd to vomits - History

Answer 3

History:

• sx: vomits, number, colour/quality (blood, bilious), onset. cramps,
• REDF: palpitation, muscle weakness, haemodynamic instability, neurological changes
• PMHx, FamHx,
• Meds
• SNAP

Question 4

Hypokalaemia 2nd to vomits - Examination

Answer 4

Examination:

• General observation + vital signs
• Fluid assessment

Question 5

Hypokalaemia 2nd to vomits - Investigations

Answer 5

Investigations:
- Key/diagnostic: ECG, UEC

• Bedside: ECG, vitals, VBG, urinary potassium
• Bloods: UEC, FBC
• Imaging: nil indicated at this stage

Question 6

Hypokalaemia 2nd to vomits - Management

Answer 6

Management:
Hypokalaemia:
- Oral replacement (mild - mod)
- IV replacement (KCl mini bags - 1 mini-bag is 0.1 increase on serum potassium) - if severe symptomatic hypokalaemia

Nausea/Vomiting

• anti-emetics (ondansetron, dexamethasone etc)
• fluid replacement
• correct other electrolyte imbalances (hypomagnasaemia contributes to increased potassium losses
• discontinue drugs which may worsen hypokalaemia (diuretics)