Non-inflammatory Myopathy of Endocrine Origin in Dogs

This form of non-inflammatory myopathy is a type of muscle disease caused by endocrine maladies such as hypo- and hyperthyroidism. However, non-inflammatory myopathy of endocrine origin has also been associated with corticosteroid use.

Symptoms and Types

• Muscle weakness
• Loss of muscle bulk
• Stiffness
• Cramps
• Regurgitation
• Difficulty in swallowing (dysphagia)
• Hoarseness (dysphonia)

Causes

Ultimately, this type of non-inflammatory myopathy is due to an endocrine disorder -- such as hyperadrenocorticism, hypothyroidism, or hyperthyroidism -- but may be immune-mediated or neoplastic in nature.

Diagnosis

You will need to give a thorough history of your dog’s health, including the onset and nature of the symptoms, to the veterinarian. He or she will then conduct a complete physical examination as well as a biochemistry profile, urinalysis, and complete blood count (CBC) to determine the type of endocrine disorder. Your veterinarian will also conduct thyroid and adrenal gland functions tests to confirm the diagnosis.

X-rays are conducted to evaluate pharyngeal and esophageal functions -- especially in patients with regurgitation and dysphagia -- while muscle samples are sent to veterinary pathologist for further evaluation.

Treatment

Treatment will depend on the underlying cause of this disease. However, if the disease is due to an adverse reaction to corticosteroids, your veterinarian will adjust the dose or stop the corticosteroid administration altogether, which usually help in resolving the symptoms. Surgery may also be required in non-inflammatory myopathy cases with tumors.

Living and Management

Dogs with this disorder will require special feeding techniques. You will briefed about elevating feeding and adding various foods to the dog's diet, especially foods of different consistencies. In cases of severe regurgitation, your veterinarian will place a feeding tube into the dog's stomach to ensure proper nutrition. He or she will also show you how to use the feeding tube correctly, and will assist in setting up a feeding schedule. In addition, dogs may need physical therapy to strengthen their muscles and reduce wasting and weakness.

Overall prognosis depends on the underlying cause and extent of disease. If the disease is due to an adverse reaction to corticosteroids, for example, prognosis is positive if the treatment is stopped immediately. Muscle strength and mass should normalize within a few weeks.