💉 Vet Insights on Multiple Myeloma in Dogs and Cats: Symptoms, Diagnosis & Treatment in 2025 🐾

By Dr Duncan Houston, BVSc

Multiple myeloma is a rare but serious cancer in pets. As a veterinarian, I've seen firsthand the confusion and concern this diagnosis brings to pet owners. This article provides an in-depth look at what multiple myeloma means for your dog or cat in 2025—from causes and symptoms to diagnosis, treatment options, and how to care for your companion throughout their journey. 🧬

What Is Multiple Myeloma? 🔬

Multiple myeloma is a cancer of plasma cells, which originate from B cells—a type of white blood cell. These plasma cells normally produce antibodies to protect against infections. In multiple myeloma, they multiply uncontrollably, disrupting normal immune and bone marrow function.

How It Affects Dogs and Cats 🐶🐱

• 📉 Plasma cells crowd out healthy blood cell production in the bone marrow.
• 🦴 Bone damage and immune system issues are common complications.
• 🧫 In cats, plasma cell tumors often form outside the bone marrow—typically in organs like the spleen or liver.

Causes and Risk Factors ⚠️

While the exact cause is still unclear, several potential triggers have been identified:

• 🧬 Genetic predisposition
• 🦠 Viral infections
• ☠️ Exposure to carcinogens (cancer-causing substances)
• ♻️ Chronic immune system stimulation

Unfortunately, due to the rare nature of the disease, predicting which pets may develop it remains difficult.

Symptoms of Multiple Myeloma 🚨

Symptoms can be subtle and overlap with other conditions, making early diagnosis challenging.

Common Signs to Watch For

• 😴 Lethargy or weakness
• 🤮 Vomiting and diarrhea
• 🥩 Loss of appetite
• 🚰 Increased thirst and urination
• 🚶 Trouble walking or unsteady gait
• 🩸 Signs of bleeding (e.g., nosebleeds, bleeding gums, bruising)

Secondary Conditions (Paraneoplastic Syndromes) 🧠🦴

These result from the impact of plasma cell overproduction on the body:

• 🧠 Kidney disease
• 💀 Bone loss (osteolysis)
• 🩺 Bleeding disorders
• 🔥 Chronic infections due to reduced immune function
• 🩸 Hyperviscosity syndrome (thickened blood)
• ⚖️ High calcium levels (hypercalcemia)

Diagnosis: How Vets Confirm Multiple Myeloma 🧪

Given the vague symptoms, multiple tests are typically needed to reach a diagnosis.

Laboratory Testing 🧫

• Complete Blood Count (CBC): Checks red/white blood cell and platelet levels.
• Serum Biochemistry Profile: Evaluates organ health and protein levels.
• Serum Protein Electrophoresis: Detects abnormal antibody (globulin) levels.
• Urinalysis: Assesses kidney function and protein loss.

Imaging and Biopsies 🖥️

• 🦴 X-rays: Reveal bone lesions from osteolysis.
• 📸 Ultrasound: Examines liver, spleen, and other organs.
• 🧬 Bone Marrow Aspiration/Biopsy: Confirms presence of abnormal plasma cells.

Treatment Options 💊

While multiple myeloma is not usually curable, treatment can significantly improve quality of life and lifespan.

Chemotherapy 📦

• 💊 Melphalan + Prednisone: Standard first-line therapy in dogs.
• 💉 Chlorambucil: May be used in cats or dogs that can't tolerate melphalan.
• ⚖️ Dosage is carefully managed to avoid bone marrow suppression and immune dysfunction.

Supportive Care 🩺

Pets may require additional therapies depending on secondary issues:

• 💧 IV fluids for kidney support
• 🧴 Antibiotics to prevent or treat infections
• 🩸 Blood transfusions for anemia or clotting issues
• 🧼 Diet modifications and appetite stimulants

Survival Times and Prognosis 📊

Dogs 🐶

• With Treatment: 220–930 days
• Without Treatment: Significantly shorter, with quality of life often deteriorating quickly

Cats 🐱

• With Treatment: 42–281 days
• More variable response depending on whether tumors are in bone marrow or external organs

Important Note: Pets often improve within 2–4 weeks of starting treatment. Many regain energy and appetite, extending their quality time with family. 💞

Living with a Myeloma Diagnosis 🐾

When your pet is diagnosed, here are key ways you can support them:

• 🧼 Provide a calm, clean environment
• 🧘 Minimize stress and maintain a regular routine
• 💊 Administer medications consistently as prescribed
• 📋 Monitor for side effects and report changes promptly to your vet
• 🧑‍⚕️ Attend regular follow-ups for blood tests and health evaluations

Final Thoughts 📝

Multiple myeloma in dogs and cats can feel overwhelming, but with today’s veterinary advancements, there’s hope. While it's rarely curable, appropriate treatment dramatically improves both survival and comfort. Knowledge, early intervention, and strong collaboration with your veterinarian are your best allies.

If you need support, don't hesitate to contact Ask A Vet or download the Ask A Vet app for 24/7 guidance from licensed professionals. 🐶🐱📱