Dog Muscle Spasms: Common Causes and When To Call Your Vet

Dog muscle spasms can be alarming to pet parents.

Muscle spasms or tremors in dogs can appear as minor shaking in one body part or may affect the entire body. The spasms can be rapid or slow in frequency and range from mild to debilitating.

Muscle spasms in dogs may indicate a simple issue or something more serious.

If this is the first time your dog has had a muscle spasm or it affects their behavior otherwise, having a checkup with your veterinarian is a good idea to ensure they are healthy.

By observing your dog’s abnormal movements at home and taking a short video, you can help determine if your dog's muscle spasms are of concern.

What Are Dog Muscle Spasms?

Dog muscle spasms are involuntary muscle movements that appear as shaking, twitching, shivering, or trembling.

Muscle spasms are like seizures in dogs in that both involve involuntary muscle movements.

However, seizures are due to abnormal brain activity and cause unconsciousness.

Dog muscle spasms, on the other hand, can be caused by a variety of underlying issues, and affected pups remain conscious, responsive, and aware.

Muscle spasms in dogs are generally not serious, but they can be painful, especially if they persist for a long time.

Common Causes of Dog Muscle Spasms

Dog muscle spasms can have many causes.

First, consider whether the spasms could be a normal reaction to your dog’s current situation.

Ask yourself:

• Is your dog shivering because they are cold or frightened?

• Are they excited to see you return from a long day at work?

• Does your pup become anxious around unfamiliar people?

• Are their nap-time tremors due to a vivid a vivid dream or nightmare?  

These are completely normal reasons why a dog would have muscle spasms.

Age may also be a factor.

Puppies can have normal muscle tremors as their nervous system develops. Elderly dogs may develop muscle spasms after strenuous exercise due to muscle fatigue.

Most of the time, minor muscle spasms in dogs are nothing to worry about.

However, longer or more intense spasms should cause concern. Common medical reasons for muscle spasms include:

• Pain—Physical discomfort due to pain, fever, or nausea can cause muscle tremors.

  • These tremors may be localized or involve the whole body.

• Toxin exposure—Toxins that commonly cause muscle spasms include snail bait products and other pesticides and insecticides. Xylitol, chocolate, grapes/raisins, mushrooms, marijuana, alcohol, and caffeine can also cause involuntary muscle spasms.

  • Toxin ingestion commonly causes whole-body tremors. An overdose of certain flea and tick preventives and treatments can also cause muscle tremors. Isoxazoline products, such as NexGard®, can cause seizures/muscle spasms in dogs that are already prone to other seizure disorders.

• Idiopathic head tremors—This type of muscle spasm is common in Boxers, English Bulldogs, Beagles, and Doberman Pinschers.

  • Idiopathic head tremors in dogs are often mistaken for focal seizures; however, they don’t respond to medications and can be corrected by having the dog focus intently on something, such as a toy or treat.

• Infectious disease—Canine distemper can cause muscle spasms ranging from minor to serious that are often long-lasting or permanent. These muscle tremors can involve one or multiple body parts.

• Metabolic disease—Various metabolic diseases can cause tremors that typically involve the entire body. Metabolic-related causes of dog muscle spasms include:

  • Low blood calcium (hypocalcemia)—Calcium is needed for muscle contractions, and low blood levels can cause dogs to have diffuse muscle tremors. This commonly develops in female dogs after they give birth and is known as eclampsia. Low blood calcium can be life-threatening if not treated promptly.

  • Low blood sugar (hypoglycemia)—Dog muscle tremors can develop if a dog’s body doesn’t have enough energy to allow normal function. The brain is especially sensitive to low glucose levels, and minor trembling, muscle spasms, or even seizures can occur if hypoglycemia develops.

  • Dehydration

  • Too much exercise

• Generalized idiopathic tremor syndrome—Also known as Shaker syndrome, this condition causes whole-body tremors. Although the cause is unknown, the tremors are caused by inflammation of the part of the brain that controls body movements.

Are Dog Muscle Spasms an Emergency?

While minor dog muscle spasms are not an emergency, spasms accompanied by other symptoms or a change in behavior or level of alertness can be serious or even life-threatening.

Your dog should be evaluated by a veterinarian if their muscle spasms are accompanied by any of the following:

• Vomiting

• Change in mentation (i.e., less alert, depressed)

• Unresponsiveness

• Toxin ingestion

If your dog develops muscle tremors after recently delivering a litter of puppies, she should be seen by your veterinarian immediately.

How Veterinarians Diagnose Dog Muscle Spasms

To diagnose dog muscle spasms, your veterinarian will take a thorough medical history (including previous vaccinations) and perform a physical exam, including a detailed neurologic assessment to rule out brain or spinal cord involvement.

The more information you can provide, the better—including any toxins your dog could have been exposed to or ingested.

Your veterinarian may recommend diagnostic testing to rule out certain medical conditions.

Testing may include:

• Blood work

• Urine testing

• X-rays

• Ultrasound

• MRI

• Cerebrospinal fluid (CSF) analysis

Blood and urine testing—as well as CSF analysis—can help your vet diagnose certain infectious diseases, inflammation, or metabolic disorders.

X-rays of the chest may be taken to look for evidence of heart or lung involvement.

An abdominal ultrasound may be performed to evaluate the internal organs. Advanced diagnostics, such as an MRI, are often performed by a veterinary neurologist.

If all your dog’s test results are normal, your veterinarian may make a diagnosis of idiopathic tremor syndrome.

Treatment of Dog Muscle Spasms

Treatment of dog muscle spasms depends on the underlying cause.

Initially, your dog may need to stay in the hospital for observation and to initiate treatment, which may involve:

• Intravenous (IV) fluids and electrolytes for hydration and to treat low blood calcium or glucose

• Heat support in the form of a heated blanket or Bair Hugger™

• Cold therapy with running water or ice packs, if your dog has a fever

• Pain medication (such as gabapentin or carprofen)

• Muscle relaxants (methocarbamol)

• Stretching and massage

Less serious causes of muscle tremors—such as anxiety—may be treated with calming supplements, environmental enrichment, and anti-anxiety medications, if necessary.