Cushing's syndrome (and possibly disease)

The serum cortisol measurements show a substantial elevation in both morning and evening levels as compared with the reference range, and the diurnal variation is minimal (results repeated below). Cortisol and cortisol metabolites (17-OH-Corticosteroids and 17-Ketosteroids) in a 24 hour urine collection are also significantly elevated. Morning ACTH is mildly elevated above the reference range, but that is distinctly abnormal because it should be substantially suppressed at these serum cortisol levels.

                                           Patient            Reference
TSH (S)                                   3.2 uU/ml           0.7 - 7.0
T3, Total (S)                             160 ng/dl            75 - 200
T4, Total (S)                             6.2 痢/dl            4.6 - 12
Prolactin (S)                              14 ng/ml       Nonpreg.  <20
LH, mid-follicular (S)                      6 mU/ml              5 - 20
FSH, mid-follicular (S)                    10 mU/ml            2.6 - 16
Cortisol
    24:00 (S)                              37 ug/dl                  <5
    08:00 (S)                              49 ug/dl              5 - 25
ACTH, 08:00 (P)                           135 pg/ml                <100
Cortisol (24 hr urine)                    160 ug                20 - 90
17-OH-Corticosteroids (24 hr urine)      11.9 mg                  3 - 8
17-Ketosteroids (24 hr urine)            18.8 mg                 5 - 15

(S = serum specimen)

The other pituitary hormones (Prolactin, LH, and FSH) are within normal concentration ranges, as are the thyroid tests. As an aside, the normal TSH is most important here; a T3 uptake should be assayed along with the T4 to allow calculation of the FTI, which is proportional to free T4. Total T3 is of limited usefulness in this setting.

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