Multiple Myeloma in Dogs and Cats

1 Symptoms

Multiple myeloma averages onset at 5.5 to 9.2 years in dogs and 8.3 to 9.3 years in cats, with cats slightly more often affected than dogs.

Main signs are lameness, bone pain, weakness, and pathological fractures, along with anemia, abnormal bleeding, palpable masses, lethargy, and weight loss. Cats may show pale mucous membranes, fever, and chronic infection.

Nerve compression by tumor causes partial paralysis. X-rays show multiple or single areas of bone dissolution across the long bones, ribs, spine, and skull, or general osteoporosis. Bloodwork reveals a normal-cell, normal-color anemia, and marrow sampling shows mature and immature plasma cells with a marked rise in total serum protein.

2 Causes and Transmission

Multiple myeloma is not contagious. It is a malignant tumor of plasma cells arising in the bone marrow and elsewhere, with excess immunoglobulin production driving the signs.

The exact cause is unknown, and clinical signs vary with the underlying disturbance.

3 Diagnosis

A veterinarian combines X-rays showing bone destruction with blood tests for anemia and high total protein, and a bone marrow aspirate revealing plasma cells.

Because signs overlap with other illnesses, this combination of imaging, lab work, and marrow sampling is needed to confirm the diagnosis.

4 Treatment

Treatment centers on chemotherapy and prevention of secondary infection. The disease is often fatal and cannot be cured by surgery or medication alone, so care focuses on controlling complications.

Infections and fever are managed with appropriate antibiotics, and bone pain is relieved with veterinary-directed pain medication to improve comfort and mobility.

5 Prevention

There is no known prevention for multiple myeloma. Because it is progressive, early recognition of lameness, weakness, or bleeding helps start supportive care sooner.

Regular senior wellness testing can flag anemia and high protein early, guiding further work-up.