Cushing syndrome and addison disease

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The adrenal cortex produces three major classes of steroids: glucocorticoids, (2) mineralocorticoids, and (3) adrenal androgens. Consequently, normal adrenal function is important for -modulating intermediary metabolism and immune responses through glucocorticoids; blood pressure, vascular volume, and electrolytes through mineralocorticoids; secondary sexual characteristics (in females) through androgens. The adrenal axis plays an important role in the stress response by rapidly increasing cortisol levels. Adrenal disorders include hyperfunction (Cushing's syndrome) and hypofunction (adrenal insufficiency) as well as a variety of genetic abnormalities of steroidogenesis.

Transcript of Cushing syndrome and addison disease

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CUSHING SYNDROME AND ADDISON

DISEASE

Presented by Dr. PANKAJ YADAVdrpankajyadav05@gmail.com

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The adrenal cortex produces three major classes of steroids:

(1)glucocorticoids,(2) mineralocorticoids, and (3) adrenal androgens. Consequently, normal adrenal function is important for -modulating intermediary metabolism and immune

responses through glucocorticoids;- blood pressure, vascular volume, and electrolytes

through mineralocorticoids;- secondary sexual characteristics (in females) through

androgens. - The adrenal axis plays an important role in the stress

response by rapidly increasing cortisol levels. - Adrenal disorders include hyperfunction (Cushing's

syndrome) and hypofunction (adrenal insufficiency) as well as a variety of genetic abnormalities of steroidogenesis.

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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

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A constellation of clinical abnormalities due

to chronic exposure to excess of cortisol or

related corticosteroid

described by Harvey Cushing in 1932

Definition

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CAUSES OF CUSHING’ S SYNDROME

ACTH-dependent causesACTH-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 (IATROGENIC)

Etiology and Pathophysiology

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COMMON CAUSES OF ECTOPIC ACTH SECRETION

Small cell carcinoma of the lung50%

Endocrine tumors of foregut origin35%Thymic carcinoidIslet cell tumor Medullary carcinoma thyroidBronchial carcinoid

Pheochromocytoma 5%Ovarian tumors 2%

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Clinical FeatureHypercotisolism

Lipid mobilization -

Lipid catabolism -

Lipid redistribution

Moon-face

buffalo hump

truncal obesity

Violaceous striae

Hepatic glucose production-

Insulin resistance

Glucose intolerance

protein metabolism negative nitrogen balance

disruption of water and electrocytes metabolism

Proximal muscle weaknessDependent edema

Hypertension

Hypokalemic metabolic alkalosis

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Frequency(%)

Weight gain 90“Moon facies” 75Hypertension 75

Violaceous striae 65Hirsutism 65Glucose intolerance 65Proximal muscle weakness 60Plethora 60Menstrual dysfunction 60Acne 40Easy bruising 40Osteopenia 40Dependent edema 40Hyperpigmentation 20Hypokalemic metabolic alkalosis 15

CLINICAL FEATURES OFGLUCOCORTICOID EXCESS

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Clinical manifestations

Cortisol levels in blood are normally elevated at 8 A.M.

and decrease to less than 50% by midnight except in

infants and young children in whom a diurnal rhythm is

not always established.

In patients with Cushing syndrome this circadian rhythm

is lost, and cortisol levels at midnight and 8 A.M. are

usually comparable.

Urinary excretion of free cortisol is increased. This is best

measured in a 24-hr urine sample and is expressed as a

ratio of micrograms of cortisol excreted per gram of

creatinine.

Diagnosis

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Dexamethasone is an exogenous steroid that provides negative feedback to the pituitary to suppress the secretion of ACTH.

This steroid is unable to pass the blood brain barrier which allows this test to assess a specific part of the hypothalamic-pituitary-adrenal axis. Specifically, dexamethasone binds to glucocorticoid receptors in the pituitary gland, which lies outside the blood brain barrier, resulting in regulatory modulation

A single-dose dexamethasone suppression test is often helpful; a dose of 25–30 μg/kg (maximum of 2 mg) given at 11 P.M. results in a plasma cortisol level of less than 5 μg/dL at 8 A.M. the next morning in normal individuals but not in patients with Cushing syndrome.

A low dose dexamethasone suppresses cortisol in individuals with no pathology in endogenous cortisol production. A high dose dexamethasone exerts negative feedback on pituitary ACTH producing cells but not on ectopic ACTH producing cells or adrenal adenoma.

Dexamethasone suppression test

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Low-dose A normal result is decrease in cortisol levels

upon administration of low-dose dexamethasone.

Cushing's disease involve no change in cortisol on low-dose dexamethasone, but inhibition of cortisol on high-dose dexamethasone

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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

Suppression tests

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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

ACTH Stimulation test

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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

CRH stimulation test

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Etiology diagnose (especially for pituitary or adrenal)

◦ Metyrapone (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

Metyrapone Test

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Pituitary CT has a sensitivity of about 50% for identifying microadenomas

MRI has 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

Imaging diagnosis

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Cushing’ s disease:

Adrenal adenoma:

Adrenal carcinoma:

Ectopic ACTH Syndrome:

Chronic, moderate clinical features can be suppressed 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

Etiological diagnosis

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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 )

Treatment

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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

Medical therapy of Cushing’ s Disease

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Steroidogenic inhibition◦ Mitotane ◦ Metyrapone ◦ Aminoglutethimide ◦ Ketoconazole

Neuromodulatory treatment◦ Bromocriptine ◦ Cyproheptadin ◦ Valproic acid ◦ Octreotide

Glucocorticoid receptor antagonist◦ RU486

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The original description of Addison's disease"general languor and debility, feebleness of the heart's action, irritability of the stomach, and a peculiar change of the color of the skin"summarizes the dominant clinical features.

Addison's disease results from progressive destruction of the adrenals, which must involve >90% of the glands before adrenal insufficiency appears

ADDISON’S DISEASE

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PRIMARY ADRENAL INSUFFICIENCYCongenital adrenal hyperplasia Anatomic destruction of gland (chronic or acute)"Idiopathic" atrophy (autoimmune, adrenoleukodystrophy)Surgical removalInfection (tuberculous, fungal, viralæ especially in AIDS patients)HemorrhageInvasion: metastaticMetabolic failure in hormone production Enzyme inhibitors (metyrapone, ketoconazole, aminoglutethimide) Cytotoxic agents (mitotane) ACTH-blocking antibodiesMutation in ACTH receptor geneAdrenal hypoplasia congenitaSECONDARY ADRENAL INSUFFICIENCYHypopituitarism due to hypothalamic-pituitary diseaseSuppression of hypothalamic-pituitary axis By exogenous steroid By endogenous steroid from tumor

Classification of Adrenal Insufficiency

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Frequency of Symptoms and Signs in Adrenal Insufficiency

Sign or Symptom Percent of Patients  

Weakness 99  

Pigmentation of skin 98  

Weight loss 97  

Anorexia, nausea, and vomiting 90  

Hypotension (<110/70) 87  

Pigmentation of mucous membranes 82 

Abdominal pain 34  

Salt craving 22  

Diarrhea 20  

Constipation 19  

Syncope 16  

Vitiligo 9  

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General: K+↑ Na+↓ glucose ↓ uraemia, mild acidosis, Ca2+ ↑ eosinophilia, neutropenia. lymphocytosis. anaemia, abnormal LFTs,

INVESTIGATIONS

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The short test compares blood cortisol levels before and after 250 micrograms of tetracosactide (intramuscular or intravenous) is given.

If, one hour later, plasma cortisol exceeds 170 nmol/l and has risen by at least 330 nmol/l to at least 690 nmol/l, adrenal failure is excluded.

If the short test is abnormal, the long test is used to differentiate between primary adrenal insufficiency and secondary adrenocortical insufficiency.

ACTH stimulation test

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The long test uses 1 mg tetracosactide (intramuscular). Blood is taken 1, 4, 8, and 24 hr later.

Normal plasma cortisol level should reach 1000 nmol/l by 4 hr. In primary Addison's disease, the cortisol level is reduced at all stages, whereas in secondary corticoadrenal insufficiency, a delayed but normal response is seen.

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In Addison’s disease ACTH is iniappropriately high

Low in secondary causes.

ACTH:

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To assess mineralocortocoid status, Adrenal antibodies

Plasma reninactivity and aldosterone:

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Look for signs of previous TB, eg calcification.

Have a low threshold far further investigations for TB, especially if autoantibodies are negative, eg CT adrenal glands.

AXR (plain abdominal films) and CXR:

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All patients with adrenal insufficiency should receive specific hormone replacement.

Replacement therapy should correct both glucocorticoid and mineralocorticoid deficiencies.

Hydrocortisone (cortisol) is the mainstay of treatment. The dose for physiologic replacement (~10 mg/M2/24 hr of hydrocortisone).

Patients are advised to take glucocorticoids with meals or, if that is impractical, with milk or an antacid, because the drugs may increase gastric acidity and exert direct toxic effects on the gastric mucosa.

To simulate the normal diurnal adrenal rhythm, two-thirds of the dose is taken in the morning, and the remaining one-third is taken in the late afternoon.

TREATMENT

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Since the replacement dosage of hydrocortisone does not replace the mineralocorticoid component of the adrenal hormones, mineralocorticoid supplementation is usually needed. This is accomplished by the administration of 0.05 to 0.1 mg fludrocortisone per day by mouth. Patients should also be instructed to maintain an ample intake of sodium (3 to 4 g/d).

TREATMENT

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In female patients with adrenal insufficiency, androgen levels are also low. Thus, some physicians believe that daily replacement with 25 to 50 mg of DHEA orally may improve quality of life and skeletal density.

TREATMENT

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Complications of glucocorticoid therapy, with the exception of gastritis, are rare at the dosages recommended for treatment of adrenal insufficiency.

Complications of mineralocorticoid therapy include hypokalemia, hypertension, cardiac enlargement, and even congestive heart failure due to sodium retention. Periodic measurements of body weight, serum potassium level, and blood pressure are useful.

ADVERSE EFFECTS

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During periods of intercurrent illness, especially in the setting of fever, the dose of hydrocortisone should be doubled.

With severe illness it should be increased to 75 to 150 mg/d.

When oral administration is not possible, parenteral routes should be employed

Likewise, before surgery or dental extractions, supplemental glucocorticoids should be administered.

Special Therapeutic Problems

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Table 331-9. Glucocorticoid Preparations

Estimated Potencyb 

Commonly Used Namea Glucocorticoid Mineralocorticoid  

SHORT-ACTING

Hydrocortisone 1 1  

Cortisone 0.8 0.8  

INTERMEDIATE-ACTING

Prednisone 4 0.25  

Prednisolone 4 0.25  

Methylprednisolone 5 <0.01  

Triamcinolone 5 <0.01  

LONG-ACTING

Paramethasone 10 <0.01  

Betamethasone 25 <0.01  

Dexamethasone 30-40 <0.01  

a The steroids are divided into three groups according to the duration of biologic activity. Short-acting preparations have a biologic half-life <12 h; long-acting, >48 h; and intermediate, between 12 and 36 h. Triamcinolone has the longest half-life of the intermediate-acting preparations.

b Relative milligram comparisons with hydrocortisone, setting the glucocorticoid and mineralocorticoid properties of hydrocortisone as 1. Sodium retention is insignificant for commonly employed doses of methylprednisolone, triamcinolone, paramethasone, betamethasone, and dexamethasone.

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A Checklist for Use Prior to the Administration of Glucocorticoids in Pharmacologic Doses

-Presence of tuberculosis or other chronic infection (chest x-ray, tuberculin test)

-Evidence of glucose intolerance or history of gestational diabetes mellitus

-Evidence of preexisting osteoporosis (bone density assessment in organ transplant recipients or postmenopausal patients)

-History of peptic ulcer, gastritis, or esophagitis (stool guaiac test) Evidence of hypertension or cardiovascular disease

-History of psychological disorders

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Supplementary Measures to Minimize Undesirable Metabolic Effects of Glucocorticoids

-Monitor caloric intake to prevent weight gain.

-Restrict sodium intake to prevent edema and minimize hypertension and potassium loss.

-Provide supplementary potassium if necessary.

-Provide antacid, H2 receptor antagonist, and/or H+,K+-ATPase inhibitor therapy.

-Institute alternate-day steroid schedule if possible. Patients receiving steroid therapy over a prolonged period should be protected by an appropriate increase in hormone level during periods of acute stress. A rule of thumb is to double the maintenance dose.

-Minimize osteopenia by Administering gonadal hormone replacement therapy: 0.625-1.25 mg conjugated estrogens given cyclically with progesterone, unless the uterus is absent; testosterone replacement for hypogonadal men

-Ensuring high calcium intake (should be approximately 1200 mg/d)

-Administering supplemental vitamin D if blood levels of calciferol or 1,25(OH)2 vitamin D are reduced

-Administering bisphosphonate prophylactically, orally or parenterally, in high-risk patients

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1. Adrenal crisis may be a rapid and overwhelming intensification of chronic adrenal insufficiency, usually precipitated by sepsis or surgical stress.

2. Alternatively, acute hemorrhagic destruction of both adrenal glands can occur in previously well subjects.

3. In children, this event is usually associated with septicemia with Pseudomonas or meningococcemia (Waterhouse-Friderichsen syndrome).

4. In adults, anticoagulant therapy or a coagulation disorder may result in bilateral adrenal hemorrhage.

ACUTE ADRENOCORTICAL INSUFFICIENCY

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Treatment is directed primarily toward repletion of circulating glucocorticoids and replacement of the sodium and water deficits.

intravenous infusion of 5% glucose in normal saline solution should be started with a bolus intravenous infusion of 100 mg hydrocortisone followed by a continuous infusion of hydrocortisone at a rate of 10 mg/h.

TREATMENT

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