Neuromuscular Disorders in Cats

A number of conditions can affect the complex network of nerves that direct your cat's muscles. Cats with these nerve-muscle disorders may exhibit strange behavior such as spastic movements and spontaneous contractions. Consult your veterinarian if you believe your cat has a disorder affecting her nerves and muscles, as early intervention is important for treatment or management of these neuromuscular conditions in cats.

Two main components of your cat's nervous system are the brain and the peripheral nerves. The peripheral nerves send signals from the brain to your cat's organs and extremities to regulate all the processes that keep her alive. Some peripheral nerves control involuntary processes such as digestion, breathing and heart rate. Others send voluntary signals, such as those used for walking or playing with a toy. 

There are a number of neuromuscular disorders that affect cats, but most manifest similar symptoms. Schedule an appointment with your veterinarian immediately if your cat exhibits one of the following symptoms of neuromuscular disorders in cats:

• Seizures
• Muscle weakness
• Paralysis
• Absence of reflexes (hyporeflexia)
• Uncoordinated movements
• Loss of muscle tone (hypotonia)
• Loss of control of body movements (ataxia)
• Weakness after physical exertion
• Crouched stance

Types

The following are the most common types of neuromuscular disorders in cats: 

• Motor neuron disease: Involves the death of nerve cells that control skeletal muscles.
• Tetanus: Unusual in cats, causes stiff paralysis in an extremity upon infection.
• Diabetic polyneuropathy: Affects cats with diabetes whose blood sugars are poorly controlled. These cats experience paralysis and atrophy that progresses over time.
• Drug-induced neuropathies: Affect cats who have been exposed to a toxic chemical, such as fertilizers or chemotherapy, that damages nerves.
• Myasthenia gravis: leads to tremors, stiff muscles, spinal flexion, and labored breathing from paralysis in the larynx. Myasthenia gravis is an inherited neuromuscular disorder.
• Muscular dystrophy: affects male cats and manifests with  excessive production of saliva, hopping while running, stiff neck, vomiting, and difficulty exercising.

There are many causes of neuromuscular disorders in cats. Some conditions are inherited or congenital (present at birth), while others are acquired after trauma or infection with a bacteria, virus or parasite. Once your veterinarian diagnoses your cat, he can explain the possible causes of that particular neuromuscular disorder in more detail.

Your veterinarian will begin the diagnostic process with a thorough physical examination of your cat, including the collection of a comprehensive history. If a veterinarian suspects your cat is suffering from a neuromuscular disorder, this physical examination will include an evaluation of the cat's gait for weakness, limping, stumbling, tripping or walking in circles. A righting test, whereby a cat is placed on its back and observed as it recovers its standing position, is often performed to test coordination. A wheelbarrow test offers insights into the functioning of your cat's front legs. 

Your veterinarian will also palpate the neck and front legs to search for areas of pain or loss of muscle tone. The trunk and hind quarters may be evaluated for abnormal posture or muscle tone. Your veterinarian may also inquire into the recent whereabouts or dietary habits of your cat. 

Several laboratory tests are appropriate for the diagnosis of neuromuscular disorders in cats. Blood tests may be ordered to rule out exposure to a neurotoxic substance. Myasthenia gravis and infections can also be detected using blood tests. 

A spinal tap involves the removal of cerebrospinal fluid from the base of a cat's skull. Depending on your cat's symptoms, a culture of spinal fluid may be ordered to indicate cancer, encephalitis, infection, or internal bleeding related to trauma. An electromyogram (EMG), which tracks the transduction of electrical impulses through the nerves, is another useful tool in the diagnostic process.

Treatment options for neuromuscular disorders in cats vary as greatly as their causes. Infections will be treated with antibiotic, antifungal, antiparasitic, or antiviral drugs. Surgery may be appropriate to repair a nerve-muscle junction that has undergone some trauma.

For conditions that cannot be cured, anticonvulsant, anti-inflammatory or steroid medication can be used to manage symptoms. Only your veterinarian is qualified to prescribe medications for your cat or alter her treatment plan.

Some forms of neuromuscular disease will resolve quickly with treatment, while others will require lifelong management. Cats with persistent paralysis may be candidates for a wheelchair. Certain medications may also be administered to relieve pain, inflammation or convulsions. Regardless of the particulars of your cat's condition and treatment plan, follow-up appointments are a cornerstone of management for these cats to track recovery and rehabilitation or recommend environmental or behavioral changes to better manage your cat's condition.