Inflammatory Muscle Diseases in Cats

Veterinarians use the term, “myopathies” to describe diseases that cause damage to occur in muscle tissue in cats. Conditions that cause an inflammatory reaction in the cat’s muscles are known as “myositides”. There are a variety of causes for these muscle diseases and they can produce a multitude of symptoms.

Cats can develop diseases that affect their muscles and overall health. While many cats never develop problems, some develop inflammatory muscle diseases that can cause uncomfortable symptoms to occur. 

If your cat develops an inflammatory muscle disease, he may display a variety of symptoms. These symptoms depend primarily on the cause of the disorder. The following is an overview of the most common symptoms associated with these diseases in household cats:

• Stiff muscles
• Overall muscle weakness
• Pain when walking
• Intolerance to activity and exercise
• Lesions on the skin
• Swelling of the muscles
• Forward bend of the neck
• Loss of appetite
• Change in gait
• Muscle pain
• Lameness
• Dry skin
• Dull coat
• Fat deposits underneath the skin
• Enlargement of the esophagus
• Vomiting
• Obesity
• Loss of agility
• Lethargy

Types

There are several different types of conditions that can cause an inflammatory response in cats. Here are a few examples:

• Fatty tissue diseases
• Cancers
• Muscle weakness disorders
• Medications
• Immune-mediated diseases

There are a variety of conditions that can cause inflammatory muscle disorders in felines. The following is a list of some of the most commonly diagnosed in domestic cats:

• Polymyositis (inflammation of skeletal muscle)
• Dermatomyositis (muscle inflammation accompanied by skin lesions)
• Tumors
• Hypokalemic polymyopathy (a metabolic muscle disorder)
• Steatitis, also known as "yellow fat disease"

Veterinarians need specific information to aid in the diagnosis of any medical condition. Most doctors begin by asking the owner detailed questions regarding the cats past medical conditions, birth history and symptoms. He will also need to know when the symptoms first appeared and if they have increased in severity.

After taking a complete medical history, the doctor will perform an examination. He will evaluate the cat’s neurological capabilities, gait and motor skills. In addition to this exam, the doctor will run a battery of laboratory tests. After drawing a blood sample, a complete biochemical profile and a complete blood count will be performed. A urinalysis will be done, as well. Additional lab tests may be performed to determine the levels of creatine kinase enzyme, which will reveal if any muscle tissue damage is present. 

The treatment for inflammatory muscle diseases in cats depends largely upon the cause of the condition. Cats that have malignant or benign tumors invading the muscle tissue may undergo a biopsy. This test is done by inserting a small needle into the tumor and taking a sample of cells. If there is a cancerous tumor present, the doctor may operate or amputate the affected limb. 

If yellow fat disease is the diagnosis, cats are usually given a diet high in Vitamin E and other important antioxidants, since vitamin deficiency is the primary cause of this condition. Medications such as anti-inflammatory medications are not usually helpful in reducing the pain and inflammation associated with this disease. 

Vitamin supplements may also be given to cats with hypokalemic polymyopathy. This disease occurs when the cat is deficient in potassium. If an early diagnosis is made, cats with this condition will improve with the proper potassium supplements and high quality foods. 

Recovery time depends primarily on the cause of the condition and the treatment necessary. Most cats receiving treatment for vitamin deficiencies begin to show signs of improvement in 6 to 8 weeks. However, this may not be true for every cat and the doctor will most likely want to monitor the cat every few weeks until a full recovery is made. If this is the case, it is important for owners to return for all appointments and notify the veterinarian if any new symptoms develop. 

If a limb is amputated due to a tumor in the muscle, the cat may recover within a few months. Most cats adapt quickly to a loss of the limb and are able to function fairly normally. Laser treatments to the wound may help speed healing and reduce the pain associated with this type of surgery.

Cats that undergo surgery for cancerous tumors may have a more difficult recovery. The amount of time involved depends on how invasive the cancer was and if it had spread to any other organs. Cats that receive chemotherapy or radiation may undergo treatment for several months. The treatment, recovery time and management of cancerous tumors depend on the type of tumor present. Cats with aggressive forms of cancer or widespread tumors may not have a favorable outlook. Veterinarians may recommend euthanasia for cats with this type of cancer. In many cases, this is the most humane treatment for animals that are suffering and have no hope of recovery.