Feline Hypocalcaemia: Recognising a Serious Metabolic Emergency

Hypocalcaemia in cats causes severe neuromuscular signs including tetany and seizures, and requires prompt recognition and treatment to prevent life-threatening deterioration.

Key Facts

Hypocalcaemia (abnormally low blood calcium) can result from hypoparathyroidism, post-thyroidectomy, eclampsia, and renal disease.
Post-surgical hypoparathyroidism following bilateral thyroidectomy is a significant clinical risk.
Eclampsia (puerperal tetany) occurs in lactating queens with high calcium demands from milk production.
Clinical signs include muscle tremors, tetany, facial rubbing, stiff gait, hypersalivation, and seizures.
Severe hypocalcaemia can cause cardiac arrhythmias and respiratory failure.
Emergency treatment involves slow intravenous calcium gluconate infusion under cardiac monitoring.
Maintenance management requires oral calcium supplementation and often vitamin D therapy.
Ionised calcium measurement is more clinically relevant than total calcium in many disease contexts.

Welfare Considerations

Hypocalcaemia causes one of the most distressing acute clinical presentations in feline medicine — spontaneous muscle contractions, facial spasms, and tetanic seizures that the cat cannot control or escape. The fear response to involuntary muscle activity compounds the physical suffering. Post-thyroidectomy hypocalcaemia, the most avoidable form, occurs when parathyroid glands are damaged during surgery — rigorous post-operative monitoring is essential to detect and treat it before seizures occur. Eclampsia in lactating queens is often unrecognised until severe because early signs (restlessness, muscle twitching) are subtle. Owner education about post-surgical monitoring and recognition of eclampsia signs in nursing queens is life-saving welfare intervention.

What You Can Do

After thyroid surgery, monitor for trembling, facial rubbing, or stiff movement at 24, 48, and 72 hours.
If you observe hypocalcaemia signs in a post-surgical or nursing cat, seek emergency care immediately.
Supplement lactating queens with appropriate calcium if they show early signs of eclampsia.
Do not over-supplement calcium during pregnancy — this paradoxically increases eclampsia risk by downregulating calcium receptors.
Ask your vet about ionised calcium monitoring post-thyroidectomy for more accurate assessment.
Educate yourself about eclampsia risk if you breed cats — early recognition saves lives.