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Hypercortisolism (Cushing’ s Syndrome). Definition . A constellation of clinical abnormalities due to chronic exposure to excess of cortisol or related corticosteroid . It is rare disorder It occurs as a result of primary tumors of adrenal gland that hypersecrete cortisol
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Definition • A constellation of clinical abnormalities due to chronic exposure to excess of cortisol or related corticosteroid
It is rare disorder • It occurs as a result of primary tumors of adrenal gland that hypersecrete cortisol excess ACTH secretion that may be of pituitary or nonpituitary sources
Anatomy and Histology AdrenalGland Cortex Medulla Zonaglomerulosa Zonafasciculata Zonareticularis aldosterone cortisol Adrenalandrogen catecholamines
Normal pattern of ACTH and cortisol secretion • Pulsatile secretion • Circadian rhythm
When stimulated by ACTH, the adrenal gland secretes cortisol and other steroid hormones. ACTH is produced by the pituitary gland and released into the petrosal venous sinuses in response to stimulation by corticotropin-releasing hormone (CRH) from the hypothalamus
Etiology and Pathophysiology TABLE 204-2. CAUSES OF CUSHING’ S SYNDROME ACTH-dependent causes ACTH-secreting pituitary tumor ( Cushing’ s disease ) Pituitary CRH-secreting neoplasm ( ectopic CRP syndrome ) Nonpituitary ACTH-secreting neoplasm ( ectopic ACTH syndrome ) ACTH-independent causes Adrenal adenoma Adrenal carcinoma Micronodular adrenal disease McCune-Albright syndrome Massive macronodular adrenal diease Pseudo-cushing Syndrome Factitious or surreptitious glucocorticoid administration
TABLE 204-3. COMMON CAUSES OF ECTOPIC ACTH SECRETION Small cell carcinoma of the lung 50% Endocrine tumors of foregut origin 35% Thymiccarcinoid Islet cell tumor Medullary carcinoma thyroid Bronchial carcinoid Pheochromocytoma 5% Ovarian tumors 2%
Diagnosis • Clinical manifestations • Lab findings • Plasma cortisol and rhythm (RIA) • Urinary free cortisol 17-hydroxycortisteriod 17-ketosteriods • Plasma ACTH
Clinical Features Hypercotisolism protein metabolism negative nitrogen balance disruption ofwater and electrocytesmetabolism Lipidmobilization Hepatic glucose production Lipidcatabolism Lipidredistribution Insulinresistance Moon-face buffalo hump truncal obesity Violaceousstriae Dependent edema Hypertension Hypokalemic metabolic alkalosis Proximal muscle weakness Glucose intolerance
TABLE 204-1. CLINICAL FEATURES OF GLUCOCORTICOID EXCESS Frequency(%) Weight gain 90 “Moon facies” 75 Hypertension 75 Violaceousstriae 65 Hirsutism 65 Glucose intolerance 65 Proximal muscle weakness 60 Plethora 60 Menstrual dysfunction 60 Acne 40 Easy bruising 40 Osteopenia 40 Dependent edema 40 Hyperpigmentation 20 Hypokalemic metabolic alkalosis 15
FIGURE . Multiple wide striae on the abdomen of a patient with Cushing's disease.
Suppression tests • Screening test • 1mg DX P.O at midnight • Plasma cortisol (PF) at 7-8 am next day • PF suppressed: Normal • PF NOT suppressed: Cushing’ s Syndrome
Suppression tests • Low dose DX suppression test • DX 0.5 mg q6h P.O 2 days • Urinary free cortisol decreased: Normal • Urinary free cortisol NOT decreased: Cushing’ s Syndrome
Suppression tests • Large dose DX suppression test • D.X 2mg q6h P.O 2 days • Urinary free cortisol reduced 50%: Cushing’s disease (Pituitary adenoma) • Urinary free cortisol NOT reduced 50%:Adrenal tumor, carcinoma, ectopic ACTH Syndrome
ACTH Stimulation test • ACTH 25u intravenously 8h • 2-5 fold increase in urinary free cortisol in Cushing’ s disease • Plasma cortisol and urinary free cortisol increase in half of adrenal adenoma patients • No response in adrenal carcinoma
CRH stimulation test • Etiology diagnose (especially for pituitary ACTH-dependent or ectopic ACTH syndrome) • A newer approach is to combine a CRH stimulation test with a dexamethasone suppression test(4mg ). • method : 1 µg / kg of CRH is administered intravenously. ACTH and cortisol levels are measured before CRH injection and 15, 30, 45, 60, 90 and 120 minutes after injection. • A rise in the cortisol value of 20 percent or more above basal level or a rise in the ACTH value of at least 50 percent above basal level is considered evidence for an ACTH-dependent lesion
Metyrapone Test • Etiology diagnose (especially for pituitary or adrenal) • Metyrapone 2-3g (30mg/kg) P.O at midnight • Urinary 17-OHCS, Plasma ACTH,11-deoxycortisol more above basal level : Cushing’s disease (Pituitary adenoma) • No response in adrenal carcinoma , tumor, ectopic ACTH Syndrome
Imaging diagnosis • Pituitary CT has a sensitivity of about 50% for identifying microadenomas • MRIhas increased sensitivity but is not 100% predictive • If diagnostic doubt need bilateral inferior petrosal sinus sampling for ACTH • Adrenal ultrasonography---first choice • Abdominal CT will allow identification of adrenal pathology • Somatostatin scintigraphy to identify sites of ectopic hormone production
Etiological diagnosis • Chronic, moderate clinical features can besuppressed by large dose test • Shorter course , mild features can NOT be suppressed by large dose test • Acute onset, progressive course, hyperandrogenic effect predominate, palpable mass, low ACTH • Appear suddenly, progress rapidly, not typical manifestation of Cushing’s syndrome, hyperpigmentation, hypokalemia, high ACTH • Cushing’ s disease: • Adrenal adenoma: • Adrenal carcinoma: • Ectopic ACTH Syndrome:
Differential diagnosis • Simple obesity • General obesity, long history, over nourished • Narrow and short striae • Urinary free cortisol can be suppressed by screening ( overnight ) test and/or low-dose DX suppression test • Normal diurnal rhythm, almost normal plasma cortisol • Type 2 DM • Normal plasma cortisol and rhythm • Once blood glucose controlled, urinary free cortisol turns to normal • Alcoholic Cushingnoid Syndrome • No drinking for one week, plasma cortisol and urinary free cortisol become normal • Depression • Lack of clinical manifestation of Cushing’s Syndrome
Treatment • Cushing’s disease • Transsphenoidal microadenomectomy • Pituitary radiation • Bilateral total adrenolectomy • Drugs • Adrenal adenoma and carcinoma • Surgical removal • Drugs ( mitotane, metyrapone, ketoconazole ) for nonresectable or metastatic carcinoma • Ectopic ACTH Syndrome • Surgical removal of the ectopic tumor • Chemotherapy, radiotherapy • Drugs ( mitotane, metyrapone, ketoconazloe )
Medical therapy of Cushing’ s Disease • Purpose • Correct metabolic abnormalities before attempted surgical cure • Palliate surgically noncurable disease • Achieve remission in patients for whom surgery is unlikely to achieve satisfactory long term results
Steroidogenic inhibition • Mitotane • Metyrapone) • Aminoglutethimide • Ketoconazole • Neuromodulatory treatment • Bromocriptine • Cyproheptadin • Valproicacid • Octreotide • Glucocorticoid receptor antagonist • RU486
Consideration question • What is etiology and classification of Cushing’ s Syndrome ? • What is clinical manifestations of Cushing’ s Syndrome ?