A 42 year old woman presents with irregular menstruation for 1 year, along with 10 kg of weight gain during the same period, despite an unchanged diet. She also complains of insomnia, fatiguability, and an intermittent mild generalized headache. Her medical, surgical and family histories are unremarkable, and she is not on any medications. However, she has been a heavy drinker for 20 years, consuming 2 to 3 units of alcohol daily. There is no history of smoking or recreational drug use. A complete blood count and fasting plasma glucose are within normal parameters, but her lipid profile reveals an elevated LDL of 117 mg/dL, and a low HDL of 37 mg/dL.
Blood Urea: 23 mg/dL (<50) Serum Creatinine: 0.4 mg/dL (<1.5) Total Bilirubin: 1.1 mg/dL (<1.0) ALT: 46 U/L (<40) AST: 35 U/L (<35) ALP: 132 U/L (<140) GGT: 420 U/L (<45) INR: 1.0 (0.9-1.1)
Thyroid Profile: TSH, free T3, and free T4 levels are all normal. Growth Hormone levels: within normal parameters.
Following administration of 1 mg of dexamethasone, morning plasma cortisol: 0.58 micromol/L (<0.05)
24-hour urinary free cortisol: 549 nmol/24h (55-250) A repeat test is performed; the new value is 510 nmol/24h