If Your Cat Is Constantly Thirsty — Signs of Adrenal Tumors and When to Diagnose

Oncology/CancerDiseasesMeongsiljang Veterinary Advisory Board

Feline adrenal tumors are malignant or benign growths that disrupt normal hormone production, and early detection significantly improves treatment outcomes. This guide provides a comprehensive overview of key symptoms, diagnostic methods, and treatment strategies.

What Are Feline Adrenal Tumors?

Image of the anatomical structure of a cat's adrenal glands

Feline adrenal tumors are benign or malignant growths arising from the adrenal glands. When these tumors autonomously overproduce hormones, they can cause a variety of systemic symptoms. In cats, functional adrenal tumors that excessively secrete aldosterone are relatively well-documented, though tumors secreting cortisol or sex hormones also occur. - Hormone overproduction: Excess aldosterone (primary hyperaldosteronism) leads to hypokalemia, muscle weakness, and excessive thirst and urination, often accompanied by insulin-resistant diabetes mellitus. - Benign tumors: Unilateral tumors confined to one adrenal gland can be surgically removed via adrenalectomy. - Malignant tumors: These can invade surrounding blood vessels and tissues or metastasize, making treatment more complex and highlighting the importance of early detection. - Hormonal imbalance: Depending on the hormones secreted, multiple organs can be affected, resulting in diverse symptoms. Early diagnosis and appropriate treatment significantly influence the prognosis.

What Are the Main Causes of Adrenal Tumors?

The exact cause of adrenal tumors in cats remains unclear. These tumors are believed to form when cells in the adrenal cortex or medulla proliferate abnormally, resulting in either functional or nonfunctional growths. - Age: Most commonly reported in middle-aged to senior cats (approximately 5–16 years old). - Breed and Sex: For primary hyperaldosteronism, no distinct breed or sex predisposition has been reported. - Hormonal Imbalance: Adrenal tumors can autonomously overproduce hormones such as aldosterone, cortisol, and sex hormones. - Internal Physiological Changes: Tumor-related changes within the adrenal tissue itself are considered the primary cause, rather than external stimuli. - Tumor Characteristics: These growths range from benign adenomas to malignant adenocarcinomas, with malignant tumors tending to invade surrounding tissues.

Image of a cat's adrenal hormone test results

What Are the Key Symptoms and Signs?

In the early stages, symptoms of feline adrenal tumors are often subtle and easy for owners to overlook. However, as the condition progresses, clear warning signs emerge. It’s important to watch for these changes closely.

Excessive thirst and urination: Your cat may drink more water than usual and visit the litter box more frequently, a condition known as polydipsia-polyuria.

Increased appetite: You might notice your cat eating more than usual, a symptom called polyphagia.

Skin changes: The skin can become thin and fragile, and wounds may take longer to heal.

Muscle weakness: Low potassium levels (hypokalemia) can lead to muscle weakness, making it difficult for your cat to walk or hold its head up.

Recurrent infections: Your cat may experience frequent recurring infections of the skin, respiratory tract, or urinary tract.

Lethargy: You may notice a decrease in activity levels, with your cat appearing tired or listless throughout the day.

Image of excessive thirst and urination symptoms in cats

Symptoms Requiring Immediate Veterinary Visit

If your cat suddenly shows severe muscle weakness, lethargy, difficulty breathing, or decreased consciousness, you should take them to the vet immediately. This could be an emergency caused by severe hypokalemia or postoperative adrenal insufficiency (hypocorticism). Adrenalectomy carries risks of complications such as bleeding during or after surgery and adrenal insufficiency, which can lead to rapid deterioration, making early intervention essential.

How Is Diagnosis Performed?

Diagnosing adrenal tumors in cats requires a comprehensive approach that combines several different tests. - Blood tests: These check for electrolyte and metabolic abnormalities, such as serum potassium levels (hypokalemia), blood glucose, and liver enzymes. If necessary, plasma aldosterone concentration is also measured. - Urinalysis: This evaluates the excretion of urinary glucocorticoids (cortisol) and helps determine if the cat has diabetes. - ACTH stimulation and dexamethasone suppression tests: These are used to assess adrenal function and identify any abnormalities in hormone secretion. - Imaging: Abdominal ultrasound is used to detect adrenal masses, while CT scans evaluate the tumor’s size, location, and whether it has invaded surrounding blood vessels or tissues. However, imaging alone cannot definitively distinguish between benign and malignant tumors. - Fine-needle aspiration and histopathology: Ultrasound-guided fine-needle aspiration can help determine whether the tumor originates from the cortex or medulla, but it has limitations in distinguishing between benign and malignant cases.

Ultrasound images of feline adrenal tumors

Treatment Methods and Step-by-Step Approach

Treatment is tailored to each cat based on the tumor’s characteristics, size, whether it has spread, and the cat’s overall health. - Surgical treatment: Unilateral adrenal tumors can be completely removed through adrenalectomy, offering the potential for a cure. However, because the risk of death from complications such as bleeding during or after surgery, or adrenal insufficiency, can be as high as one in three (approximately 20–33%), careful preoperative evaluation is essential. - Medical treatment: If surgery is not feasible, symptoms are managed through medical therapy that regulates hormone secretion. - Hormone and electrolyte monitoring: Regular checks of potassium levels and hormone concentrations are necessary even after surgery. - Recurrence and metastasis management: Recurrent tumors or metastasis are detected early through regular imaging and blood tests. - Comprehensive care: Combining surgery, medication, and ongoing management yields the best treatment outcomes.

Home Care Points

Daily care is the key to successful treatment after surgery or during medication. - Consistent Medication: Administer medications at the same time every day to avoid missing doses. - Dietary Management: Provide nutritionally balanced food appropriate for your cat’s weight and health status. - Environmental Control: Maintain a quiet, stable environment to minimize stress. - Daily Monitoring: Record daily observations such as appetite, bowel movements, and activity levels, and share them with your veterinarian. - Regular Check-ups: Do not skip scheduled veterinary examinations, even while your cat is on medication. - Watch for Warning Signs: Seek immediate veterinary care if emergency symptoms such as sudden shock or decreased consciousness occur.

Image of a stable home environment for cats

Breed-Specific Precautions and Recurrence Prevention

Adrenal tumors are relatively rare in cats, but they are most commonly reported in middle-aged to senior cats (approximately 5 to 16 years old). Since no clear breed or sex predisposition has been identified to date, regular health check-ups are recommended as your cat ages. Even after surgery, it is important to regularly monitor hormone and electrolyte levels and perform imaging studies to detect any recurrence early. If you notice any sudden changes while your cat is on medication, consult your veterinarian immediately.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Can feline adrenal tumors be treated?

Unilateral adrenal tumors can often be cured with an adrenalectomy, and the prognosis is better the earlier the tumor is detected. However, because surgery carries a risk of complications, thorough pre- and post-operative assessments and regular follow-up care are essential.

Are adrenal tumors common in cats?

No, adrenal tumors are relatively uncommon in cats. They are most often seen in middle-aged to senior cats (roughly 5 to 16 years old), and there is no known strong predisposition for any particular breed or sex.

What side effects can occur during medication treatment?

Your pet may experience a decreased appetite, vomiting, diarrhea, or lethargy. If any unusual symptoms occur while taking the medication, consult your veterinarian immediately.

What is the likelihood of recurrence after surgery?

Adrenalectomy carries a mortality rate of up to one-third (approximately 20–33%) due to risks such as intraoperative or postoperative bleeding and adrenal insufficiency, so careful evaluation is essential. The likelihood of recurrence or metastasis varies depending on the tumor’s characteristics, making regular postoperative check-ups important.

What other conditions can cause symptoms similar to those of adrenal tumors?

Conditions such as diabetes, chronic kidney disease, and hyperthyroidism can also cause symptoms like excessive thirst, increased urination, and changes in appetite. Diagnostic testing is necessary for an accurate diagnosis.

7 Factors Determining Prognosis and Life Expectancy in Dogs with Tumors, According to Veterinarians

7 Key Points of Canine Tumor Immunotherapy Selected by Veterinarians — From Principles to Selection Criteria

7 Criteria Veterinarians Recommend for Choosing Canine Tumor Biopsy and Fine-Needle Aspiration

Our Puppy with Kidney Failure — When Peritoneal Dialysis Is Needed and Key Care Points

Nephrotoxic Drugs and Substances Dangerous to Your Dog — Symptoms of Toxicity and Key Response Points

Lethargy and Vomiting in Dogs — Signs of Leptospiral Kidney Involvement and When to Visit the Vet

Complete Guide to Canine Chronic Kidney Disease IRIS Stages 1–4: Symptoms and Treatment Strategies by Stage

If Your Dog’s Kidneys Are Failing, Blood Pressure Is Also at Risk — Hypertension Symptoms and Diagnosis/Treatment Key Points

Why Is Phosphorus a Problem in Our Dog's Kidney Disease? — A Complete Guide to Hyperphosphatemia and Phosphate Binders

My Dog Ate Grapes — Signs of Nephrotoxicity Leading to Kidney Failure Requiring Immediate Veterinary Care

References

[1] Hosgood, G. et al. (2020) Feline Adrenal Gland Disorders: Clinical Features, Diagnosis, and Management. Journal of Feline Medicine and Surgery, 22(5), 397–408.

[2] Plumb's Veterinary Drug Handbook, 9th Edition. (2022). Wiley-Blackwell.

[3] American College of Veterinary Internal Medicine (ACVIM). (2021) Consensus Statement on Feline Adrenal Disease. Journal of Veterinary Internal Medicine, 35(4), 1677–1689.