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 cat’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.