Hyperadrenocorticoid myopathy in dogs, also sometimes called Cushing myopathy, is a metabolic myopathy associated with hyperadrenocorticism. Any dog with natural or iatrogenic hyperadrenocorticism may develop clinical signs; however, all reported cases in the literature either had pituitary-dependent hyperadrenocorticism or were receiving exogenous steroids (1, 2).
The classic clinical signs of hyperadrenocorticism—polyuria/polydipsia, polyphagia, and a pendulous abdomen—are usually observed before clinical signs of hyperadrenocorticoid myopathy are observed. The latter include the following:
stiff or stilted gait (most noticeable in the pelvic limbs)
weakness
muscular atrophy (see ).
Diagnosis is based on observation of clinical signs of the myopathy in a patient with hyperadrenocorticism. Affected dogs might also have an elevated serum CK activity and abnormal electromyographic and muscle biopsy findings. Subclinical myopathy has been diagnosed in dogs with hyperadrenocorticism and can also occur in patients with atypical hyperadrenocorticism.
Treatment of hyperadrenocorticoid myopathy involves addressing the underlying cause of hyperadrenocorticism; however, the long-term prognosis for resolution of the myopathy varies.
For other metabolic myopathies in dogs, see the Overview for this chapter.
For More Information
Also see pet owner content regarding hyperadrenocorticism (Cushing disease) in dogs.
References
Greene CE, Lorenz MD, Munnell JF, Prasse KW, White NA, Bowen JM. Myopathy associated with hyperadrenocorticism in the dog. J Am Vet Med Assoc. 1979;174(12):1310-1315.
Hovious K, Fowler K, Beasly M, Pancotto TE. Cushing's myopathy in dogs: prevalence, clinical abnormalities, and response to treatment. Animals (Basel). 2024;14(21):3109. doi:10.3390/ani14213109
