suddenly stiff: muscular hypertonicity in dogs

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when a dog's suddenly very stiff: muscular hypertonicity
Posted by Dr. Rebecca Jackson on Feb 01 2014

Updated September 26, 2019

For this week’s topic, I was asked by one of my co-workers to write about a condition that affects dogs called muscular hypertonicity.

Although not a common condition, muscular hypertonicity does tend to show strong breed predilection in the terrier and spaniel breeds. Assumed to have a prominent genetic component, this is a condition that we still don’t know a great deal about, and it can vary a bit between the different breeds it seems to effect.

What does muscular hypertonicity in dogs look like?

It is usually preceded by exercise and excitement and results in a dog suddenly becoming stiff and collapsing. Dogs don’t lose consciousness and usually recover within a few minutes. Sometimes recovery can take up to a couple of hours, and your pet may be stiff for quite a while afterwards. Some pet parents have reported that their dogs rub their faces along the floor prior to an episode, and some observe muscle rippling in the affected limbs.

There are no specific tests for the disease. Bloodwork and specific muscle and nerve testing may be done to rule out other causes of the clinical signs. Usually history, clinical signs, familial history and normal screening lab work is strongly indicative of the condition. Fortunately, this is rarely a life threatening condition. In rare instances, prolonged muscle contractions can lead to hyperthermia (over heating) and this can be life threatening.

Can muscular hypertonicity be cured?

Once afflicted, this is a lifelong condition. Some dogs have only infrequent episodes, and so their pet parents choose not to intervene. Some dogs aren’t that lucky and so medical intervention is required. There are a couple of medications that have shown to decrease and/or minimize clinical signs. These medications are given daily for the life of the dog, and are often covered by pet insurance.

Muscular hypertonicity in dogs is not a common condition, but it occurs frequently enough to warrant a discussion. If you suspect your dog is suffering from this condition, contact your veterinarian. They may request that you video tape an episode, and they will likely run a few different tests in order to rule out other possible causes of these clinical signs. Depending on your dog’s specific breed, there are other similar conditions that your vet may need to rule out first.

As always, you are your pet’s best advocate! If you think something is going on, don’t hesitate to contact your trusted veterinarian for advice. That is what we are here for!