Diagnosis
Table 2. Conditions Associated with Hypercortisolism in the
Absence of Cushing's Syndrome
a
Conditions
Some clinical features of Cushing's syndrome may be present
• Pregnancy
• Depression and other psychiatric
conditions
• Alcohol dependence
• Glucocorticoid resistance
• Morbid obesity
• Poorly controlled diabetes mellitus
Unlikely to have any clinical features of Cushing's syndrome
• Physical stress (hospitalization, surgery,
pain)
• Malnutrition, anorexia nervosa
• Intense chronic exercise
• Hypothalamic amenorrhea
• CBG excess (increased serum but not
urine cortisol)
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Whereas Cushing's syndrome is unlikely in these conditions, it may rarely be present. If there is a high
clinical index of suspicion, the patient should undergo testing, particularly those within the first group.
Table 3. Selected Drugs That May Interfere with the Evaluation
of Tests for the Diagnosis of Cushing's Syndrome
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Drugs
Drugs that accelerate dexamethasone metabolism by induction of CYP 3A4
• Phenobarbital
• Phenytoin
• Carbamazepine
• Primidone
• Rifampin
• Rifapentine
• Ethosuximide
• Pioglitazone
Drugs that impair dexamethasone metabolism by inhibition of CYP 3A4
• Aprepitant/fosaprepitant
• Itraconazole
• Ritonavir
• Fluoxetine
• Diltiazem
• Cimetidine
Drugs that increase CBG and may falsely elevate cortisol results
• Estrogens • Mitotane
Drugs that increase UFC results
• Carbamazepine (increase)
• Fenofibrate (increase if measured by
HPLC)
• Some synthetic glucocorticoids
(immunoassays)
• Drugs that inhibit 11β-HSD2 (licorice,
carbenoxolone)
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is should not be considered a complete list of potential drug interactions.
Data regarding CYP3A4 obtained from iupui.edu/flockhart/table.htm.
Cushing's Syndrome
