If Your Cat Keeps Stumbling and Drinking Excessive Water — Causes and Treatment of Multiple Myeloma

Oncology/CancerDiseasesMeongsiljang Veterinary Advisory Board

Feline multiple myeloma is a malignant tumor that occurs when abnormal immune cells proliferate excessively in the bone marrow. Early detection and proper management can significantly improve survival time.

What Is Feline Multiple Myeloma?

The proliferation of abnormal immune cells in a cat's bone marrow

Feline multiple myeloma is a malignant tumor caused by the excessive proliferation of abnormal immune cells in the bone marrow. This disease invades the bones, increasing the risk of bone pain and fractures, and disrupts blood production, leading to anemia. As cancer cells spread to various parts of the body, systemic symptoms may appear. Early detection and appropriate treatment are key to significantly extending survival time. In particular, if abnormal proteins are found in the bone marrow, multiple myeloma should be suspected. Since the risk of this disease increases with age, regular check-ups for senior cats are essential.

Main Causes and Pathogenesis

The exact cause of feline multiple myeloma remains unclear. While it is known to be a neoplastic disease characterized by the abnormal proliferation of plasma cells (immune cells) within the bone marrow, no single established cause or specific genetic mutation has been definitively identified. However, a key point is that multiple myeloma is suspected when monoclonal gammopathy (an abnormal protein) is detected in the blood. It is important to note that an increase in this protein can also occur in infectious diseases such as ehrlichiosis and leishmaniasis, as well as in feline infectious peritonitis (FIP). Therefore, differentiating multiple myeloma from other conditions with similar clinical signs is paramount. Ultimately, rather than pinpointing a definitive cause, the emphasis for this disease is on the early detection of abnormal findings and consistent, ongoing management.

Abnormal plasma cells found in a cat's bone marrow

Main Symptoms and Signs

Feline multiple myeloma presents with a variety of symptoms, and early detection significantly improves treatment success rates.

Bone pain: Weakened bones cause discomfort during movement, particularly in the back and legs.

Anemia: Reduced red blood cell count leads to lethargy and pale lips.

Polyuria and pollakiuria: Impaired kidney function results in increased urine volume or more frequent urination.

Loss of appetite: Discomfort reduces food intake.

Weight loss: Muscle and fat mass decrease rapidly.

Increased risk of fractures: Weakened bones are prone to breaking even from minor impacts.

A cat that is in pain and unable to move

Symptoms Requiring Immediate Veterinary Care

If your pet has a fracture, is unable to move due to severe pain, is at risk of collapsing from severe anemia, or is completely unable to urinate, you should seek veterinary care immediately.

Accurate Diagnostic Methods

Feline multiple myeloma is accurately diagnosed through a combination of tests. - Blood tests: These assess overall blood health and check for anemia or abnormal serum proteins, such as hypergammaglobulinemia. - Bone marrow biopsy: This is the most reliable method for directly confirming the presence of abnormal plasma cells in the bone marrow. - Radiography (X-rays): This evaluates characteristic bone lesions, such as bone lysis (osteolysis) or fractures. - Protein electrophoresis: This detects monoclonal gammaglobulins (M-proteins) in the blood, while urine tests may reveal Bence Jones proteinuria. Imaging studies (CT/MRI): These provide more precise assessment of the extent of bone damage. A final diagnosis is reached by comprehensively analyzing these clinical and radiographic findings along with the confirmation of monoclonal gammaglobulins.

A veterinarian collecting a bone marrow sample from a cat.

Treatment Methods and Step-by-Step Management

Treatment for feline multiple myeloma involves a combination of chemotherapy, corticosteroids, pain management, and care for bone and electrolyte complications. - Chemotherapy: Drugs such as vincristine are used to suppress tumor cell proliferation and slow disease progression. - Corticosteroids: Steroids like prednisolone are administered alongside chemotherapy to help modulate the tumor response. - Pain Management: In cases of severe bone pain, analgesic and palliative care are provided to improve the cat’s quality of life. - Bone and Electrolyte Management: We monitor and manage complications such as bone resorption, pathological fractures, and hypercalcemia. Because blood calcium levels can actually rise in multiple myeloma, calcium supplementation must be approached with caution. Treatment plans are adjusted regularly based on the cat’s condition and response, making routine check-ups and monitoring essential to successful care.

A cat receiving an intravenous injection at the veterinary clinic.

Key Points for Home Care

Feline multiple myeloma requires long-term management. Here are some key points for care at home.

Maintain a stable environment: Provide a quiet space where your cat can rest comfortably.

Diet management: Choose high-quality, nutritious food and offer small, frequent meals.

Pain monitoring: Watch for signs of pain in your cat’s movements or responses.

Regular check-ups: Schedule regular appointments with your vet for blood tests and X-rays.

Consistent medication: Stick to the prescribed medication schedule. Missing doses can reduce effectiveness.

Emotional well-being: Your warm attention and a stress-free environment are important for your cat’s comfort.

Preventing Recurrence and Breed Considerations

Feline multiple myeloma is a malignant tumor that is difficult to cure, and it can recur or progress even after treatment. However, there is no clear evidence that certain cat breeds are more prone to this condition, so regular health check-ups are essential to monitor for any subtle changes, regardless of breed.

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

Is feline multiple myeloma treatable?

While a complete cure is difficult, chemotherapy and supportive care can help alleviate symptoms and extend life expectancy, though individual responses may vary.

Does this disease only affect cats?

Multiple myeloma is a plasma cell tumor that occurs in both cats and dogs. It’s difficult to definitively say which species is more commonly affected or experiences faster disease progression, as it is relatively rare in both.

Can it be prevented?

Although there is no definitive preventive method yet, regular health check-ups and early detection are the most effective ways to manage the condition.

What should I do if my cat loses its appetite during treatment?

Loss of appetite can be a side effect of treatment. Consult your veterinarian about considering nutritional supplements or specialized diets.

How can you tell if your cat is in pain?

If your pet shows reduced mobility, vocalizes in pain, or experiences a sudden decrease in appetite, these could be signs of discomfort. Please consult with your veterinarian for a proper evaluation.

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References

[1] The Cat, Clinical Medicine and Management, 2nd Edition. Elsevier, 2023.

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

[3] American Veterinary Medical Association. Feline Oncology Guidelines. 2021.