Hereditary Muscle Disease (Non-inflammatory Myopathy) in Labrador Retrievers

By PetMD Editorial on Apr. 26, 2010

Hereditary, Non-inflammatory Myopathy in Labrador Retrievers

A myopathy is a muscular disease in which the muscle fibers do not function due to any of the common reasons, ultimately resulting in overall muscular weakness. The form of myopathy described in this article is specifically seen in Labrador retrievers, especially yellow Labs.

Symptoms and Types

Symptoms typically develop between the ages of three to four months, many of which worsen with cold weather, excitement, and exercise. In addition, improvements may be seen once the dog is allowed to rest. Some of the more common symptoms include:

Muscle weakness
Arched back
Downward flexion of head and neck
Abnormal joint posture
Excessive laying down (in some dogs)
Abnormal gait
Sudden collapse

Causes

Inherited in Labrador retrievers.

Diagnosis

You will need to give a thorough history of your dog’s health to your veterinarian, including the onset and nature of the symptoms. He or she will then perform a complete physical examination as well as a complete blood count, biochemistry profile, and urinalysis -- the results of which may indicate a mild increase of the creatine kinase enzyme (normally present in muscle, brain, and other tissues).

Your veterinarian may also take a muscle biopsy and send it to veterinary pathologist for further evaluation. The results may show abnormalities related to muscle cells.

Treatment

Treating this type of myopathy is non-specific and directed towards alleviating the symptoms. To improve muscle strength, for example, L-carnitine supplements are given to the dog.

Living and Management

Prognosis for Labradors with this form of myopathy is variable; however, most clinical signs stabilize once the dog reaches about one year of age. Do not place your Labrador in cold areas, as it may exacerbate the symptoms. In addition, due to the genetic nature of this disease, your veterinarian may recommend against breeding the dog, its parents, or littermates.