Emergency Treatment of Cats with Urethral Obstructions

Cats with urethral obstruction are one of the true feline emergencies. They may present with marked hyperkalaemia. Cardiovascular protection is paramount via administration of calcium gluconate (1-1.5 mls/kg 10% calcium gluconate) to re-establish membrane excitability. If given too quickly it will cause further bradycardia and ventricular arrhythmias. Calcium gluconate will not lower serum potassium concentration, it's benefit is predominantly in stabilising the patient prior to administration of treatments that will redistribute or excrete potassium.

Intravenous fluid therapy and relieving the obstruction are likely the two most important factors in resolving electrolyte derangements.

Redistribution of potassium using dextrose (0.5 g/kg IV bolus) increases endogenous insulin and moves potassium intracellularly. Insulin ((rapid acting insulin 0.25-0.5 IU/kg) may also be required and ongoing supplementation with dextrose to prevent hypoglycaemia is important. 2 agonists (e.g. salbutamol) stimulate the Na+/K+ ATPase pump to move potassium intracellularly. Although not evaluated in cats, giving three to four puffs of inhalational salbutamol is a quick and rapid treatment that might be helpful...

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