When an animal is presented to the veterinarian for a potential clinical problem, an initial “data base” is collected in the form of a blood panel and urinalysis, and possibly a urine culture. There are some “tip offs” to Cushing’s syndrome which may be noted and added to the list of observed symptoms as evidence.

THE STRESS LEUKOGRAM

This term refers to the relative proportions of different types of white blood cells. There is a typical pattern produced by cortisol as the body responds to stress. This pattern is called a “stress leukogram.”  If this pattern is seen in a patient that does not seem stressed, there is a possibility that an excess of cortisol is present.

ELEVATED ALKALINE PHOSPHATASE

Alkaline phosphatase (often abbreviated ALP or SAP) is one of the so-called “liver enzymes,” meaning that it is chiefly found in the liver. There is a form of this enzyme which is produced in very high levels in response to cortisol.  This enzyme is not harmful in excess levels but since such marked increases in its levels are associated with cortisol, this would be a good hint that either this patient is taking cortisone type medications or has Cushing’s disease.

ELEVATED CHOLESTEROL

This is a common finding in most endocrine diseases and, in this case, results from abnormal fat mobilization. High levels of circulating cholesterol may, as in humans, alter normal circulation and blood clotting.

UNCONCENTRATED URINE AND/OR BLADDER INFECTION

When a pet drinks excessive amounts of water, the extra water is passed as urine. As long as there is extra water, urine will be dilute.  Because of the immunosuppression associated with Cushing’s disease, evidence of bacterial infection may be present as well or such evidence may be concealed by the dilution of the urine. Ideally urine should be cultured if it is too dilute to reliably detect white blood cells or blood. Recent studies have shown that 20% of dogs with Cushing’s disease have an inapparent bladder infection.

These classic laboratory findings complement the physical examination and may lead your veterinarian to recommend definitive testing for Cushing’s Syndrome.

FELINE CUSHING’S DISEASE

In the cat, laboratory findings turn out to be similar to those in the dog except that these changes are generally referrable to uncontrolled diabetes mellitus, a common but later change in feline Cushing’s disease. In early Cushing’s disease, cats may not show obvious blood test abnormalities.