Metabolic Muscle Disease in Cats

The lack of ability to properly break down food causes two issues. First, your cat will not have the energy necessary to grow, regenerate, and use muscle tissue. Second, inappropriate amounts of by-products will build up in the muscle tissues of your cat, causing damage. Successful recovery and management of this condition will depend on timely treatment, making it important that you seek out veterinary assistance promptly once you notice symptoms.

Metabolic muscle disease is a broad classification for a variety of disorders that affect your cat’s voluntary muscles. The reference to metabolic in the name is a reference to the mechanism that causes the muscular dysfunction. With this condition, there is a failure of your cat’s metabolism to properly break down food and nutrients into appropriate building blocks used to supply energy to the muscles.

Symptoms of metabolic muscle disease in your cat may be varied, but will all revolve around an inability to properly activate and use the muscular system. Symptoms to watch for may include:

• Stumbling
• General lethargy
• Muscle atrophy, or shrinking
• Muscle swelling, which may indicate a buildup of harmful byproducts
• Failure to thrive or grow
• Weakness
• Regurgitation due to muscular failure of esophagus
• Joint pain
• Cramps
• Listlessness or unwillingness to play or exercise
• Dark urine

Metabolic muscle disease is typically a genetically inherited disease in cats. While there are numerous specific disorders that fall under the umbrella of metabolic muscle disease, they all share a common mode of inheritance. Most conditions of this nature are recessive, which means both parents must carry a gene for the condition in order for it to express in their offspring. This allows for genetic testing for some types of metabolic muscle disease to effectively weed out future incidences.

Diagnosis of metabolic muscle disease in your cat will begin with a thorough veterinary exam. At this time, you should present your veterinarian with a complete medical and physical history of your cat’s symptoms. You should pay especial attention to the onset of the condition, and any progression including approximate timeline. If your cat has recently had any dietary changes, this should also be noted and disclosed to your vet. Finally, you should present your veterinarian with the medical background or any genetic testing that may have been done on your cat’s sire or dam. All of these facts will assist your vet in pinpointing the exact condition.

Next, your veterinarian will want to take blood and tissue samples for analysis. Both of these tests should be relatively painless procedures for your cat and will involve a quick needle stick and withdrawal of blood or tissue. In some cases, your vet may want a large tissue sample, in which case your cat may need to be sedated or anesthetized to avoid pain and keep your cat still.

Your vet will examine the samples under a microscope or have them sent to an outside laboratory for a similar analysis. This will help determine the presence of by-products that indicate a metabolic condition, including inappropriate values of amino acids, glycogen and other metabolites. Finally, your vet will order a urinalysis. This will also help determine whether the products being eliminated by your pet contain the expected appropriate levels of various chemicals and proteins.

Since most forms of metabolic muscle disease in cats are inherited, treatment of the condition will focus on support of your cat’s muscular system. Initial treatment will begin with stabilizing your cat, including any imbalances of levels. This can often be accomplished by various blood filtering procedures. This type of procedure will require your cat be hospitalized at your vet’s office. 

Once your cat has attained normal levels of byproducts in their system, a management plan for the condition can be developed. This may include certain dietary alterations. Changes in diet may allow your cat to efficiently process some nutrition from their food, while eliminating the elements that they aren’t able to properly metabolize for energy. 

Certain supplements may also be given that either lower byproduct levels in the muscular cells, or help your cat properly break down nutrients into usable energy.

There is currently no known cure for metabolic muscle disease in your cat. Prognosis and recovery will depend on the severity of the condition in your cat and strict adherence to any dietary or medication regimen prescribed by your vet. 

Unfortunately, in some pets, the condition will be so severe that successful management may not be possible. In these cases, you and your vet will develop a plan that keeps your cat comfortable and maintains an appropriate quality of life.