Diagnosing & Treating Cushing’s Syndrome
Cushing's syndrome is diagnosed by physicians by measuring the levels of cortisol in the patient's body. This can be done through standard blood and urine tests, or through specialized tests.
Salivary cortisol test is a screening test for Cushing’s syndrome that involves measuring levels of cortisol in saliva between 11:00 p.m. and midnight. People with Cushing’s syndrome have an elevated level of cortisol late in the evening, when it should otherwise decrease. Saliva is collected in an absorbent material, which is then placed in a small vial and mailed to the lab for analysis. If the test is positive, it is repeated and other tests are done to confirm a Cushing’s diagnosis. The test was developed in the 1990s by Froedtert & the Medical College of Wisconsin endocrinologist James Findling, MD.
Dexamethasone suppression tests measure the response of the adrenal glands to adrenocorticotropic hormone (ACTH). This test is done when it is suspected that the body is producing too much cortisol. There are two types of dexamethasone suppression tests: the low-dose test and the high-dose test. During the test, a patient receives dexamethasone, and the patient’s cortisol levels are measured.
If a Cushing’s syndrome diagnosis is confirmed by these tests, other tests may be conducted to pinpoint the cause and determine the most appropriate treatment. Magnetic resonance imaging (MRI) may be recommended to scan for ACTH-secreting tumors that cause Cushing’s, most of which are found in the pituitary. If the MRI is inconclusive, additional tests may be requested.
Cushing's Disease Treatments
The best course of treatment for Cushing’s disease, ectopic ACTH syndrome and other forms of Cushing’s syndrome depends on the cause of the symptoms. Education frequently plays an important role in teaching patients about helpful lifestyle changes to minimize symptoms.
When Cushing’s syndrome is caused by an excessive level of cortisol due to medications, reducing the dosage may be an option. If not, treatment involves symptom relief and medication to help prevent bone loss.
Patients with Cushing’s syndrome may also receive treatment for specific symptoms, such as medication for high blood pressure, diabetes and depression.
Pituitary Tumor Surgery
When Cushing’s is caused by a pituitary tumor, the most effective treatment is surgery. Tumors may recur, however, so an annual assessment of cortisol secretion is important. If pituitary surgery does not resolve the symptoms or if the tumor recurs, several treatment options are available, including a repeat operation, radiation therapy and medication.
Adrenal Tumor Surgery
If an adrenal gland tumor is the cause, the most effective treatment is the removal of the gland through minimally invasive surgery, followed by lifelong oral steroid replacement.