Endocrine—Cushing’s Syndrome
Concept
The majority of Cushing’s syndrome cases are from an ACTH secreting tumor of the pituitary gland. Other possible etiologies include: ectopic ACTH producing tumor, adrenal adenoma, adrenal carcinoma, and bilat- eral adrenal hyperplasia. The treatment of choice is sur- gical resection.
Way Question May be Asked?
“28 y/o female referred to your office for generalized weakness, new onset diabetes and hypertension. On physical exam, she is obese and has a buffalo hump and moon facies. What do you want to do?” Might be given that the patient is referred to you with the diagnosis of Cushing’s syndrome. Examiners will not want to waste time in the history and physical stage, for the most part—but still must know just in case. Most will want to get at your algorithm for managing the patient (this goes for most scenarios).
How to Answer?
History
Steroid use
History of cancer (ACTH producing tumor of lung) Diabetes
Hypertension
Generalized weakness
Physical Exam
Buffalo hump Truncal obesity Striae
Moon facies
Diagnostic Tests
24 h urine for cortisol (most cost-effective test if inci- denteloma)
Plasma cortisol level at 8 am and 8 pm (check for loss of diurnal variation)
ACTH level, two possibilities:
(1) If elevated→pt has pituitary tumor or ectopic ACTH producing tumor
(2) Low→ pt has adrenal pathology
Dexamethasone suppression test, two possibilities (1) Suppress ACTH→ pituitary source (2) Doesn’t suppress ACTH→ ectopic cancer Then obtain CT scan:
Of head for pituitary source
Of chest/abdomen/pelvis for ectopic cancer source Of abdomen for adrenal source
Should see contralateral gland to be atrophied Should not see bilateral enlargement
If > 5 cm, suspect adrenocortical carcinoma
Surgical Treatment
Posterior unilateral adrenalectomy unless suspect malignancy
For adrenocortical carcincoma, resection includes adre- nal, kidney, and continuous structures (spleen, distal pancreas, diaphragm)
If metastatic disease present, debulk
Can use mitotane if metastatic disease or pt not a surgical candidate (adrenolytic agent destroys Zona Fasiculata)
Common Curveballs
Scenario will change with first presentation as pituitary tumor, then presentation as adrenal tumor
Will be malignant tumor
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Addisonian crisis post-op
Being asked difference between Cushing’s syndrome and Cushing’s disease
There will be an ACTH or CRF secreting tumor (typi- cally lung)
Pt won’t be a surgical candidate
Will be given results of tests you order (24 h urine cor- tisol, plasma cortisol levels, ACTH levels, dexam- ethasone suppression test)
Being asked when to order the above tests Will present as an incidenteloma
Describing surgical approach to adrenalectomy
Strikeouts
Not being able to diagnose location of tumor Not knowing treatment for pituitary tumor Not knowing treatment for adrenal tumor Performing FNA on the adrenal tumor
Not recognizing the adrenal tumor for what it is and directing therapy towards a pituitary lesion
Discussing bilateal laparoscopic adrenalectomy
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