Cushing’s Syndrome in Cats: Symptoms, Causes & Treatment

Hyperadrenocorticism, commonly known as Cushing’s syndrome in cats, is a rare but serious condition caused by excessive cortisol production from the adrenal glands. Although it is far less common in cats than in dogs, Cushing’s syndrome can significantly impact a cat’s health and quality of life. Understanding the causes, recognising symptoms, and knowing the treatment options help cat owners provide compassionate care and seek timely veterinary advice.

Causes of Cushing’s syndrome in cats

Cushing’s syndrome arises from an overproduction of cortisol, a vital steroid hormone that helps regulate metabolism, immune response, and stress management. In cats, excess cortisol levels typically result from:

• Pituitary-dependent hyperadrenocorticism: This is the most common cause, where a benign tumour or abnormality in the pituitary gland causes overstimulation of the adrenal glands.
• Adrenal-dependent disease: Less commonly, tumours or hyperplasia in the adrenal glands themselves lead to excess cortisol.
• Iatrogenic causes: Prolonged or high-dose use of corticosteroid medications (often prescribed for allergies or inflammatory diseases) can induce Cushing’s syndrome.

Advanced age is a risk factor as these hormonal imbalances tend to develop in middle-aged to older cats, usually between 5 and 17 years old. Female cats are reported to be affected slightly more often than males. Unlike many other conditions, Cushing’s syndrome is not hereditary, contagious, or preventable by vaccination.

Identifying cats at risk

There is no specific breed predisposition for Cushing’s syndrome in cats, although domestic short-haired and long-haired cats may be more commonly diagnosed simply due to their general population prevalence. The condition primarily affects mature cats, with risk increasing with age. Because the signs can be subtle and overlap with other illnesses, especially diabetes, cat owners should monitor senior cats carefully for changes in behaviour and health.

Preventing the condition

Currently, there is no guaranteed method to prevent naturally occurring Cushing’s syndrome. However, since iatrogenic causes from corticosteroid therapy are a risk factor, veterinarians recommend avoiding long-term corticosteroid use where possible and exploring alternative treatments. Maintaining a healthy weight, balanced diet, and adequate exercise supports general endocrine and metabolic health, potentially reducing risks associated with diabetes, which frequently accompanies this condition.

Recognising symptoms of Cushing’s syndrome in cats

Symptoms often appear gradually and can mimic natural ageing or other diseases. Common signs include:

• Increased thirst and urination
• Marked increase in appetite
• Weight loss or sometimes weight gain despite increased eating
• Pot-bellied appearance due to abdominal enlargement
• Thinning, fragile skin that bruises or tears easily
• Hair loss and failure to regrow coat, sometimes with curling of ear tips
• Muscle weakness and lethargy
• Loss of grooming interest leading to an unkempt coat
• Vomiting or diarrhoea in some cases

Because many cats with Cushing’s also have diabetes mellitus, fluctuating blood sugar levels might mask or complicate symptoms. Diagnosis requires veterinary evaluation using bloodwork, endocrine function tests such as the low-dose dexamethasone suppression test (LDDST), and imaging like ultrasounds or X-rays.

Treatment and prognosis

Treatment depends on the underlying cause:

• Iatrogenic Cushing’s syndrome: Gradual withdrawal of corticosteroids under veterinary supervision can sometimes reverse symptoms.
• Tumour-related disease: Medical management with the drug trilostane is commonly used to inhibit cortisol production. Surgical removal of adrenal tumours may be considered but involves significant risks and complexity.
• Pituitary tumours: Surgery is rarely performed due to the high risk; radiation therapy may be an option in some cases.

The prognosis varies widely. Early diagnosis and treatment improve a cat’s quality of life and survival, but naturally occurring Cushing’s syndrome is difficult to cure completely. Around half of affected cats may live less than a year after diagnosis despite treatment, though some respond well and maintain a good quality of life for longer with proper care.

Responsible pet ownership includes attentive observation for symptoms and working closely with a vet to manage complex conditions like Cushing’s syndrome. Educating yourself about the disease empowers you to make informed decisions supporting your cat’s wellbeing.

For more detailed veterinary advice and support, resources from International Cat Care and PetMD provide excellent guidance.