Enlarged Spleen in Cats

The spleen is an elongated organ that is on the left side of the stomach in cats. Though the organ isn't essential for living, an enlarged spleen may be a symptom of a more serious or chronic disease that will need veterinary care.

Splenomegaly, or an enlarged spleen, is a symptom of another condition or disease. The enlargement is due to inflammation, which occurs due to infiltration of abnormal cells as a result of the primary condition. The primary condition that is causing the enlargement is typically related to the function of the spleen, such as filtering blood or synthesizing antibodies in the cat's body. The cat's spleen may either enlarge uniformly over the entire organ or enlarge asymmetrically.

Because the spleen is responsible for storing and filtering blood, removing old cells and foreign bodies from the bloodstream, and helping the immune system function properly, the cat may experience a variety of symptoms that warrant investigation in order to treat the primary cause of the enlargement. 

• Lack of appetite
• Weight loss
• Enlarged lymph nodes
• Swollen abdomen
• Diarrhea
• Vomiting
• Abdominal pain/sensitivity
• Lethargy
• Weakness
• Fainting

There are a variety of causes of splenomegaly in cats, which include: 

• Abdominal injury due to trauma
• Heart failure
• Heartworms
• Inflammatory bowel disease
• Infectious disorders, such as feline infectious peritonitis
• Cancer, such as multiple myeloma and feline leukemia virus
• Bacterial infection
• Autoimmune disorders, such as systemic lupus
• Splenic torsion (rotation or twisting of the spleen)
• Fungal infections, such as histoplasmosis

The veterinarian will examine the cat, feeling for swollen lymph nodes and a swollen abdomen. In some cases, the enlarged spleen will be protruding through the abdominal skin and is noticeable with a visual examination. The veterinarian will need to know the cat's complete health history, all of the symptoms the cat is experiencing, and when symptoms first began.

A complete blood count, biochemical blood profile and a urinalysis will be taken. These tests will help the veterinarian determine the primary condition that is causing the spleen enlargement. The tests will also show how the other organs, such as the kidneys and liver, are being affected by the primary condition. The blood tests will typically also show signs of an enlarged spleen, which include a high white blood cell count, low hemoglobin levels (anemia) and abnormal cells that are causing the inflammation.

Diagnostic tests, such as an x-ray and ultrasound, will be performed. These tests will allow the veterinarian to view the spleen and the surrounding organs for any abnormalities. A fine needle aspiration may also be performed. During this test, the veterinarian will insert a thin needle into the spleen, drawing out a fluid sample for further analysis. In rare occasions, exploratory surgery may be necessary if a diagnosis isn't found with other tests.

Treatment of the enlarged spleen will depend on treating the primary condition that is causing the inflammation.

Medication

Corticosteroids may be prescribed by the veterinarian in order to reduce the inflammation in the spleen and other organs. If the enlargement is due to a bacterial infection, antibiotics will be prescribed. Autoimmune primary causes will be treated with immunosuppressants, which work to suppress the reaction of the immune system. Cancer may be treated with chemotherapy, which will work to kill the cancer cells in the cat's body. Cats who are severely anemic may need to take iron supplements. Medications to treat fungal infections may also be prescribed.

Surgery

In cases of splenic torsion or trauma, the veterinarian may need to remove all or part of the cat's spleen (splenectomy). This will be done in the hospital under general anesthesia. During surgery, the veterinarian will make a small incision in the cat's abdomen. The entire spleen or affected portion of the spleen will be removed and the blood vessels attached to the spleen will be clamped and tied. The incision site will then be closed. Surgery may also be necessary to remove any tumors or masses that have formed due to cancer.

The cat will need to continue to take medication as prescribed by the veterinarian in order to prevent the primary condition from worsening and causing the spleen to enlarge once more. Follow-up appointments to monitor labs and medication will be necessary. If the cat had surgery, it's important to care for the incision site at home to prevent infection from occurring. Keeping the cat calm and stopping strenuous activities is essential in proper recovery.