[Equine Cushing syndrome (ECS). Case report, review of its diagnosis and therapy and substantial differences from Cushing syndrome in dogs].

The research article discusses the similarities and differences between Equine Cushing’s Syndrome (ECS) and Canine Cushing’s Syndrome, focusing on pathogenesis, clinical symptoms, diagnosis, and treatment. While both syndromes result from elevated cortisol levels, differences exist in how the diseases present themselves, are diagnosed, and treated in horses and dogs.

Pathogenesis

• The study first touches on the pathogenesis of ECS and Canine Cushing’s syndrome. ECS primarily affects older horses and is often associated with excessive hormone production in the pars intermedia region of the pituitary gland.
• This results in elevated levels of adrenocorticotrope hormone (ACTH), pro-opiomelanocortin, beta-endorphines and alpha-melanocyte-stimulating hormone. Conversely, Cushing’s syndrome in middle-aged and geriatric dogs, the most frequently diagnosed endocrinologic abnormality, is often pituitary-dependent (80-85% of cases) or the result of cortisol-producing tumors in the adrenals (15-20% of cases).
• Pituitary lesions in dogs are predominantly adenomas, largely located in the pars distalis region of the gland. Only on rare occasions, they occur in the pars intermedia, unlike in horses.

Clinical Symptoms

• The clinical symptoms in both species include weight loss despite increased appetite, reduced muscle mass, altered fat deposition, and lethargy. Polydipsia/polyuria, common in dogs with Cushing’s syndrome, is usually associated with concurrent secondary diabetes mellitus in horses.
• An important distinction is that ECS in horses often leads to a condition known as hirsutism – continuous growth of the haircoat. In contrast, dogs with Cushing’s present with generalized alopecia, which often prompts the owner to seek veterinary attention.

Diagnosis and Treatment

• The article also uses a 33-year-old mare as a case study to discuss diagnostic procedures for ECS. The paper reviews diagnostic tests, highlighting variations in test responses between species.
• The treatment of ECS involves the use of dopamine-agonists like bromocriptine and pergolide, as well as cyproheptadine. The article reviews the therapeutic approach to ECS, suggesting further exploration and explanation might be beneficial.