Severe hypokalaemia in a cat with ketoacidosis: giving potassium
12-year-old female cat being treated for ketoacidosis with fluids and regular insulin. After 12 hours she shows marked weakness and cervical ventroflexion.
| Parameter | Result | Reference |
|---|---|---|
| Potassium | 2.1 mmol/L | 3.5–5.5 |
| Glucose | 260 mg/dL | 70–150 |
| Phosphorus | 3.4 mg/dL | 3.0–6.8 |
What is the most appropriate action?
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A. IV bolus of potassium chloride to correct potassium quickly
Potassium must never be given as a bolus: it can cause severe arrhythmias and cardiac arrest.
B. Stop the insulin permanently and switch to oral potassium
Insulin is still needed to resolve the ketoacidosis (it can be reduced temporarily). In a critically ill, anorexic, vomiting cat the oral route is unreliable.
C. Slow IV calcium gluconate with ECG monitoring
Calcium gluconate protects the myocardium in hyperkalaemia, not hypokalaemia. It does not correct the potassium deficit.
D. Increase the potassium chloride in the fluids without exceeding 0.5 mEq/kg/h, using an infusion pump and checking potassium every few hours
Correct. Insulin shifts potassium into cells and unmasks the total body deficit. Severe hypokalaemia causes weakness and ventroflexion in cats. The classic maximum rate is 0.5 mEq/kg/h; insulin can be reduced temporarily.
lightbulb Key takeaway
Cervical ventroflexion in a cat: think hypokalaemia (also thiamine deficiency or myasthenia). Do not exceed 0.5 mEq/kg/h, mix the bag well and label it. If hypokalaemia does not respond, measure magnesium.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.