🐾 Vet-Approved 2025 Guide: Multiple Myeloma in Dogs and Cats—Signs, Diagnosis & Treatment 🧬🐶🐱

By Dr. Duncan Houston, BVSc

Multiple myeloma is a rare but serious cancer in dogs and cats that originates in plasma cells—specialized white blood cells that produce antibodies. When these cells multiply uncontrollably, they can crowd out normal bone marrow function and lead to dangerous systemic effects 🧪🩺

🔬 What Is Multiple Myeloma?

Multiple myeloma is a plasma cell cancer affecting the bone marrow, immune system, and internal organs. These overactive cells produce excessive antibodies and trigger complications like:

• 🦴 Bone loss (osteolysis)
• 🩸 Anemia or bleeding problems
• 💧 Kidney failure
• 🧬 Increased blood thickness (hyperviscosity syndrome)
• 📉 Weakened immune defenses

🐱 In cats, plasma cell tumors often occur outside the bone marrow, like in the liver or spleen.

⚠️ Symptoms of Multiple Myeloma

• 😴 Lethargy and weakness
• 🤮 Vomiting and diarrhea
• 🍽️ Loss of appetite
• 🚰 Increased drinking and urination
• 🦵 Lameness or trouble walking
• 🩸 Bleeding gums, nosebleeds, pale gums, or bruising

These symptoms are non-specific, so diagnosis often requires thorough testing.

🧪 Diagnostic Testing

Common Tests:

• 🩸 CBC (Complete Blood Count) – checks red/white cells and platelets
• 🧪 Serum Biochemistry – looks at organ function and protein levels
• 💧 Serum protein electrophoresis – identifies abnormal antibody production
• 🧫 Bone marrow aspiration or biopsy – confirms cancer in marrow
• 🦴 X-rays/Ultrasound – checks for bone or organ involvement
• 💉 Clotting tests and urinalysis – identifies secondary complications

📉 Complications (Paraneoplastic Syndromes)

• 🧬 Kidney disease
• 🧪 High calcium (hypercalcemia)
• 🩸 Bleeding issues due to clotting problems
• 🦠 Increased infection risk from immune suppression
• 💉 Hyperviscosity syndrome from thickened blood

💊 Treatment Options

Cure is rare, but treatment can significantly improve quality of life and extend survival:

• 📦 Chemotherapy – often includes melphalan or cyclophosphamide
• 💊 Prednisone – controls inflammation and slows cancer spread
• 🩺 Supportive care – includes fluids, pain control, antibiotics, and anti-nausea meds

📈 Prognosis

• 🧬 Dogs: 220–930 day survival depending on treatment
• 🐱 Cats: 42–281 day survival (shorter if not treated)

Pets treated for multiple myeloma often show symptom improvement within a few weeks. Without treatment, survival is greatly reduced, though exact timelines vary 🕐

🩺 Monitoring & Long-Term Care

• 📅 Regular blood tests and imaging
• 📉 Monitor for relapse or progression
• 🧪 Ongoing supportive care for kidneys, calcium levels, and blood pressure

📲 Need Help Navigating a Multiple Myeloma Diagnosis?

Cancer can be overwhelming, but you’re not alone. For help understanding test results, creating a treatment plan, or weighing care options, visit AskAVet.com or download the Ask A Vet app 📱

💖 With attentive care and the right veterinary support, pets with multiple myeloma can enjoy more time, comfort, and quality of life 🐾