Diagnosis
➤ In individuals with at least one abnormal test result (for whom the results could
be falsely positive or indicate Cushing's syndrome), ES recommends further
evaluation by an endocrinologist to confirm or exclude the diagnosis (1|⊕
).
Subsequent Evaluation
➤ For the subsequent evaluation of abnormal initial test results, ES recommends
performing another recommended test (Fig. 1, 1|⊕
).
➤ ES suggests the additional use of the dexamethasone-suppressed
corticotropin-releasing hormone (Dex-CRH) test or the midnight serum
cortisol test in specific situations (Fig. 1, 1|⊕
).
➤ ES suggests against the use of the desmopressin test, except in research
studies, until additional data validate its utility (2|⊕
).
➤ ES recommends against any further testing for Cushing's syndrome in
individuals with concordantly negative results on two different tests (except in
patients suspected of having the very rare case of cyclical disease) (1|⊕
).
➤ ES recommends tests to establish the cause of Cushing's syndrome in patients
with concordantly positive results from two different tests, provided there
is no concern regarding possible non-Cushing's hypercortisolism (Table 2)
(1|⊕⊕
).
➤ ES suggests further evaluation and follow-up for the few patients with
concordantly negative results who are suspected of having cyclical disease and
also for patients with discordant results, especially if the pretest probability of
Cushing's syndrome is high (2|⊕
).
Special Populations/Considerations
➤ Pregnancy: ES recommends the use of UFC and against the use of
dexamethasone testing in the initial evaluation of pregnant women (1|⊕⊕⊕
).
➤ Epilepsy: ES recommends against the use of dexamethasone testing in patients
receiving antiepileptic drugs known to enhance dexamethasone clearance and
recommends instead measurements of nonsuppressed cortisol in blood, saliva,
or urine (1|⊕⊕⊕
).
➤ Renal failure: ES suggests using the 1-mg overnight DST rather than UFC for
initial testing for Cushing's syndrome in patients with severe renal failure
(2|⊕
).
➤ Cyclic Cushing's syndrome: ES suggests use of UFC or midnight salivary
cortisol tests rather than DSTs in patients suspected of having cyclic Cushing's
syndrome (2|⊕
).
➤ Adrenal incidentaloma: ES suggests use of the 1-mg DST or late-night cortisol
test, rather than UFC, in patients suspected of having mild Cushing's syndrome
(2|⊕⊕
).
