Acromegaly in Cats: Managing Growth Hormone Excess

Feline acromegaly results from excess growth hormone secretion, typically from a pituitary tumour, causing progressive changes to body structure and severe insulin-resistant diabetes.

Key Facts

Acromegaly is caused by a benign pituitary adenoma secreting excess growth hormone in most cases
Middle-aged to older male cats are most commonly affected, though females can develop the condition
Insulin-resistant diabetes mellitus is the most common presenting complaint in affected cats
Physical changes include enlarged paws, broad facial features, and increased body weight and size
Diagnosis requires measurement of IGF-1 (insulin-like growth factor) and pituitary imaging by MRI
Radiotherapy targeting the pituitary tumour is the most effective long-term treatment available
Stereotactic radiotherapy has achieved remission in approximately 85% of treated cats in recent studies
Without treatment, cats require very high insulin doses and progressive diabetes management becomes increasingly difficult

Welfare Considerations

Acromegaly in cats causes welfare concerns through two main pathways: the metabolic consequences of insulin-resistant diabetes and the structural changes from excess growth hormone. Uncontrolled diabetes causes thirst, frequent urination, weight loss despite good appetite, and eventual weakness. The high insulin requirements are practically and financially challenging for owners, and poorly controlled diabetes causes suffering. Pituitary tumour growth can also eventually cause neurological signs. Radiotherapy, where accessible, offers the best welfare outcome by addressing the root cause. However, access to specialist treatment is uneven, meaning many cats are managed symptomatically throughout their lives.

What You Can Do

If your diabetic cat is difficult to regulate on insulin, ask your vet to test IGF-1 levels
Seek referral to a veterinary internal medicine specialist if acromegaly is suspected
Discuss radiotherapy options with a veterinary oncologist if diagnosis is confirmed
Monitor diabetic acromegalic cats closely for signs of neurological deterioration
Work with your vet to find the minimum effective insulin dose with regular glucose monitoring
Join feline acromegaly support groups to share management strategies with other owners