Muscle Tremors in Cats

Key Takeaways

Muscle tremors are involuntary movement of the muscular tissue, often appearing similar to shivering or trembling. This symptom is not common in cats.

• Tremors may be localized to certain areas of the body or occur from head to tail

• In some instances, tremors manifest as head bobbing in response to focus on a task

• Improper function of the muscles, nerves or the parts of the brain that control movement cause tremors

• Tremors indicate a variety of underlying conditions, some of which are life threatening

• Diagnostics for a cat presenting with muscle tremors include  physical examination, blood work, urinalysis, and diagnostic imaging

• Treatment and prognosis vary widely depending on the underlying condition

A Closer Look: What are Muscle Tremors in Cats?

Muscle tremors are not a common occurrence in cats and many of the underlying conditions associated with them are serious. Unless the cat was born with cerebellar hypoplasia, muscle tremors are a rare occurrence. Adult onset muscle tremors are commonly a sign of pyrethroid toxicosis which is potentially life-threatening and requires immediate medical attention.

Intention tremors are a specific type of tremor that occurs when the animal focuses on something, such as food or a toy. The cat may be at rest, but as a stimulus, such as a toy or bowl of food is offered, the cat  experiences tremors in the neck and head. The tremors themselves are constant and obvious. Intention tremors are a primary symptom of Cerebellar Hypoplasia.

Possible Causes

The most common reasons for a cat to have tremors include: 

• Cerebellar hypoplasia • Pyrethroid toxicosis • Other toxicoses • Chronic renal failure

• Infections, tumors, or other illnesses affecting the parts of the brain that control balance, coordination and movement

• Any illness that leads to electrolyte disturbances

• Low blood sugar in inappropriately managed cats with diabetes mellitus

Risk Factors

Muscle tremors are involuntary movement of the muscular tissue. The severity varies widely depending on the underlying cause, ranging from  small twitches isolated to one group of muscles to full- body spastic movement. Tremors may be intermittent or consistent. They may come on suddenly, or be present from birth and persist throughout the cat’s life.

Testing and Diagnosis

A cat presenting with muscle tremors will undergo a general work up to determine the root cause. Useful diagnostic tests include:

• Physical Examination • Blood Work • Urinalysis  • Diagnostic imaging

Treatment depends on the diagnosis.

Similar symptoms

Muscle tremors can be mistaken for shivering. Shivering is differentiated from tremors by context and duration.  A cat is only expected to shiver when it’s extremely cold.  A cold cat does not usually show any other symptoms and the shivering stops once the cat warms up.   

Cats with feline hyperesthesia syndrome twitch excessively, and this sometimes appears similar to tremors. Twitching episodes associated with feline hyperesthesia are usually very brief, even when they are intense, and localized along the cat’s back or hindquarters. 

During sleep, a cat may twitch and move involuntarily which is a regular phenomenon and not a muscle tremor.

Seizures are a symptom of many conditions that vary widely in their presentation to such an extent that it’s difficult to differentiate them from tremors in some cases. Cats with pyrethroid toxicosis may experience both, and distinguishing them is not clinically relevant to managing the disease.

Associated Symptoms

Other symptoms occurring with  muscle tremors vary widely, but common ones include:

• Uncoordinated Walking (ataxia) • Falling over easily • Seizures • Hypersalivation

• Hypersensitivity/hyperreactivity • Vomiting