Muscle Swelling in Cats

The causes of muscle swelling vary widely from minor injuries to some types of cancer, so the associated level of concern varies accordingly.

Muscle swelling in cats can be described as:

• Generalized or focal: throughout the body or in one small area
• Acute or chronic: recently noted or ongoing
• Mild or severe
• Primary or secondary: the swelling arises solely in the muscle where it is noted or as the result of another condition

A small area of swelling present without any other symptoms is of little concern, whereas larger swellings or swellings accompanied by symptoms like pain, distress, appetite loss, or lethargy are more concerning. Consultation with a vet is recommended if a cat is showing any of these symptoms whether muscle swelling is present or not.

The following diagnostic tests are performed to determine the underlying cause for muscle swelling and the best course of treatment:

• Physical examination
• Blood work
• Diagnostic imaging
• Fine needle aspirate to collect cells from the swollen area for microscopy analysis
• Biopsy

Anything that causes swelling under the skin can be confused for muscle swelling.

Muscle swelling may be mistaken for localized inflammation of other tissues near the muscle, like bone or connective tissue. However, some aggressive cancers of bone and connective tissue can invade adjacent muscles and cause swelling this way.