Cushings Syndrome Hypercortisolism

Definitions

• Cushing's syndrome = Cortisol excess

• Cushing's disease Cushing's syndrome 2° to pituitary ACTH hypersecretion Etiologies of hypercortisolism

• Most common cause is iatrogenic Cushing's syndrome caused by exogenous glucocorticoids

• Cushing's disease (60-70%): pituitary adenoma (usually microadenoma) or hyperplasia

• Adrenal tumor (15-25%): adenoma or carcinoma

• Ectopic ACTH (5-10%): SCLC. carcinoid, islet cell tumors, medullary thyroid cancer, pheo Clinical manifestations

• Glucose intolerance or DM. HTN. obesity, and oligomenorrhea (all nonspecific)

• Central obesity, buffalo hump, moon fades, wasting of extremities, proximal myopathy.

spontaneous bruising, wide striae, osteoporosis, and hypokalemia (all more specific)

• Other: depression, insomnia, psychosis, impaired cognition, facial plethora, acne, hirsutism.

hyperpigmentaaon (if t ACTH). fungal skin infxns. nephrolithiasis, polyuria Figure 7-3 Approach to suspected Cushingi syndrome

Suspect Cushing's Syndrome Clinically

3 Options for Screening tor Hypercortisolism 24-h UFC or Overnight 1 mg DST or 11 pm Salivary Cortisol

Q and low clinical suspicion s

Not Cushing's

clinical suspicion acute illness. EtOH. depression ♦ ^

{or repeat) 24-h UFC re / after resolution of ■ illness or / combined

? Pseudo-Cushing's

Differentiate level ot defect by checking serum ACTH

ACTH dependent

Will not suppress Will suppress

chestabd MRI „ pirutlaiy MHI

ACTH ■ independent

adrenal CT or MRI

I Ectopic ACTH

I Cushing's disease"]

Adrenal tumor

CRH corticotrop«n-releasing hormone; DST - dcxamothasone suppression test; UFC - urinary free Cortisol Overnight 1 mg DST give 1 mg at 11 pm; ✓ 8 am serum Cortisol (suppression if <S pg dl); 1-2% false © (primanly used to evaluate subclinical Cushing's in Pu w adrenal "incidenatoma") 11 pm salivary Cortisol abnl if level Î; 24-h UFC abnl if level î. > 4 x ULN virtually diagnostic 48-h LD DST ♦ CRH = 05 mg q6h ■ 2 d. then IV CRH 2 h later:/ serum Cortisol 15 mln later (© - > 1.4 W df) 48-h LD DST 0.5 mg q6h ■ 2 d; ✓ 24-h UFC at base. & during last 24 h of dex (suppress if < 10% of base) 48-h HD DST 2 mg q6h 2 d. / 24-h UFC as per LD DST

O N HD DST = 8 mg at 11 pm: ✓ 9 am serum Cortisol (suppression if • 32% of baseline)

CRH test 1 pg kg IV;/ Cortisol and ACTH (© stim if > 35% î in ACTH or >20% t in Cortisol above baseline)

BIPSS Mat inferior petrosal sinus vein sampling; / petrosal:peiiphcral ACTH ratio (0 2 basal, -3 after CRH)

Treatment of Cushing's syndrome

• Surgical resection of pituitary adenoma, adrenal tumor, or ectopic ACTH-secreting tumor

• If transsphenoidal surgery (TSS) not successful — pituitary XRT. medical adrenalectomy w mitotane. or bilat surgical adrenalectomy, ketoconazole ( • metyrapone) to i Cortisol

• Glucocorticoid replacement therapy x 6-36 mos after TSS (lifelong glucocorticoid •

mineralocorticoid replacement if medical or surgical adrenalectomy)

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