Protocol Number: 02-CH-0309

Title:

The Diagnostic Performance of Screening Tests for the Diagnosis of Cushing's Syndrome

Number:

02-CH-0309

Summary:

This study will test the accuracy of screening tests for Cushing's syndrome in overweight people with signs of the disorder. Cushing's syndrome is a rare disorder caused by excess production of the hormone cortisol. Patients may have various problems, such as weight gain, high blood pressure, diabetes, infections, mood problems, trouble concentrating, and increased blood clotting. These symptoms are seen in many other disorders as well, complicating the diagnosis. The reliability of tests currently used to diagnose Cushing's syndrome is not known. To test their accuracy, subjects in this study who test positive for Cushing's syndrome will be evaluated at NIH for 2 years to either confirm or refute the laboratory results.

Patients between 18 and 75 years of age who are being treated at the George Washington University Weight Management Program (GWUWMP) may participate in this study. Candidates will be screened with a medical history, physical examination, measurement of body fat, blood tests, and oral glucose tolerance test. They will also complete a symptoms checklist and quality of life questionnaire.

Participants will be tested for Cushing's syndrome with a saliva collection, 24-hour urine collection, and dexamethasone suppression test (DST). For the DST they will take 1 mg of dexamethasone at night and report to GWUWMP the next morning for a blood draw. All specimens-blood, saliva, and urine-will be tested for cortisol levels.

People whose test results are abnormal will be seen at the NIH outpatient clinic for a medical history, physical examination, and blood tests; bedtime saliva collection; two 24-hour urine collections; and a 2-day 2-mg DST, followed by administration of corticotropin-releasing hormone (CRH). CRH is a naturally occurring hormone that causes cortisol levels to rise. Pre-treatment with dexamethasone prevents CRH from causing an increase in cortisol in healthy people, but not in patients with Cushing's syndrome. For the 2-day DST, the subject takes 0.5 mg dexamethasone every 6 hours for eight doses. Two hours after the last dose, CRH is injected through a catheter (thin plastic tube) inserted into an arm vein. Blood is drawn just before giving CRH to measure dexamethasone and cortisol levels and after giving CRH to measure cortisol levels.

People whose test results are normal will not be seen further at NIH. Those with high cortisol levels will have repeat urine and saliva tests every 2 to 8 weeks for up to 24 months, and a 1-mg DST every 3 months during routine clinic visits at GWUWMP. People whose increased cortisol is found to be due to another condition besides Cushing's syndrome will be referred for evaluation and possible treatment. Those diagnosed with Cushing's syndrome will have standard tests to identify the tumor causing the disorder, followed by standard medical and surgical treatment.

Sponsoring Institute:

National Institute of Child Health and Human Development (NICHD)

Recruitment Detail

Type: No longer recruiting/follow-up only

Gender: Male & Female

Referral Letter Required: Yes

Population Exclusion(s): Children

Eligibility Criteria: This study is not currently recruiting new subjects. If you have questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.

Special Instructions:

Currently Not Provided

Keyword(s):

Cortisol

Dexamethasone

Obesity

Pseudo-Cushing State

Hypercortisolism

Cushing's Syndrome

Recruitment Keyword(s):

Cushing Syndrome

Condition(s):

Cushing's Syndrome

Investigational Drug(s):

None

Investigational Device(s):

None

Interventions:

None

Supporting Site:

National Institute of Child Health and Human Development

Contact(s):

This study is not currently recruiting new subjects. If you have questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.

Citation(s):

Castro M, Elias PC, Quidute AR, Halah FP, Moreira AC. Out-patient screening for Cushing's syndrome: the sensitivity of the combination of circadian rhythm and overnight dexamethasone suppression salivary cortisol tests. J Clin Endocrinol Metab. 1999 Mar;84(3):878-82.

Crapo L. Cushing's syndrome: a review of diagnostic tests. Metabolism. 1979 Sep;28(9):955-77. Review.

Gold PW, Loriaux DL, Roy A, Kling MA, Calabrese JR, Kellner CH, Nieman LK, Post RM, Pickar D, Gallucci W, et al. Responses to corticotropin-releasing hormone in the hypercortisolism of depression and Cushing's disease. Pathophysiologic and diagnostic implications. N Engl J Med. 1986 May 22;314(21):1329-35.

• Questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.
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