One of the first signs of Cushing syndrome, is the loss of this diurnal variation.Cushing syndrome: In this condition, the cancer cells make ACTH, a hormone that causes the adrenal glands to make cortisol. A pot-bellied appearance.Left untreated dogs with Cushing’s are predisposed to a number of internal problems, including high blood pressure, urinary tract infections, urinary stones, pancreatitis, clot formation/stroke, diabetes, and vision loss, so early diagnosis and control are important to preventing the majority of the serious complications of this disease.Initial Screening: First-Line Biochemical Tests In healthy individuals, the level of serum cortisol reaches a peak in the morning (7-9 am) and reach the lowest level between bedtime and 2 am. What are the first signs of cushing Signs of Cushing's syndrome include: Failure or later shedding of the winter coat that may become really long, matted and curly especially around the legs.