Cushing's Syndrome Test
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Questions and Answers

What is the most common cause of Cushing syndrome today?

  • Hormone-producing lung tumors
  • The use of corticosteroid medications (correct)
  • Pituitary tumors
  • Cortisol-secreting adrenal tumors

    • What is the estimated incidence of Cushing syndrome per 1 million persons per year?

  • 3 new cases
  • 5 new cases
  • 1 new case
  • 2 new cases (correct)

    • What is the age range for the peak incidence of Cushing syndrome due to adrenal or pituitary tumor?

  • 40-50 years
  • 25-40 years (correct)
  • 20-25 years
  • 15-20 years

    • What is the estimated incidence of Cushing syndrome in children per 1 million persons per year?

    <p>0.2 cases</p> Signup and view all the answers

    What is the significance of Cushing syndrome?

    <p>It is a multitude of complications that can result from hypercortisolism</p> Signup and view all the answers

    What is the female to male ratio for developing hypercortisolism from a pituitary tumor?

    <p>8:1</p> Signup and view all the answers

    What is the prevalence of hypercortisolism from all other causes combined?

    <p>3 cases per 1 million people nationally</p> Signup and view all the answers

    What percentage of all cases of Cushing syndrome occur during adulthood?

    <p>90%</p> Signup and view all the answers

    What percentage of Cushing syndrome cases are caused by administering supra-physiologic doses of corticosteroid drugs?

    <p>The majority of cases</p> Signup and view all the answers

    What is the term used to describe the hypersecretion of ACTH by non-pituitary tumors?

    <p>Ectopic Cushing syndrome</p> Signup and view all the answers

    What is the effect of excessive circulating CRH on serum cortisol levels?

    <p>It increases serum cortisol levels</p> Signup and view all the answers

    What is the term used to describe the accumulation of fat on the back of the neck in Cushing syndrome?

    <p>Buffalo hump</p> Signup and view all the answers

    Which of the following is NOT a cause of Cushing syndrome?

    <p>Hyposecretion of corticotropin-releasing hormone by the hypothalamus</p> Signup and view all the answers

    What is the effect of Cushing syndrome on glucose levels?

    <p>It increases glucose levels</p> Signup and view all the answers

    Which of the following corticosteroids is NOT commonly prescribed?

    <p>Dexamethasone</p> Signup and view all the answers

    What is the effect of Cushing syndrome on immune and inflammatory reactions?

    <p>It inhibits immune and inflammatory reactions</p> Signup and view all the answers

    What is the effect of cortisol on T lymphocyte proliferation?

    <p>Decrease T lymphocyte proliferation</p> Signup and view all the answers

    What is a possible effect of hypercortisolism on female patients?

    <p>Excessive hair growth, especially facial hair</p> Signup and view all the answers

    What is a common physical feature of patients with hypercortisolism?

    <p>Thin arms and legs, and collection of fat in the cervical area and abdomen</p> Signup and view all the answers

    What is a possible effect of elevated aldosterone levels in hypercortisolism?

    <p>Hypokalemic alkalosis</p> Signup and view all the answers

    What is the diagnostic significance of a morning serum cortisol level of 2 µg/dL after dexamethasone administration?

    <p>It rules out Cushing syndrome with 98% certainty</p> Signup and view all the answers

    What is the significance of a low ACTH level in a patient with hypercortisolism?

    <p>It indicates ACTH-independent Cushing syndrome</p> Signup and view all the answers

    What is a possible mental symptom of hypercortisolism?

    <p>A wide range of mental symptoms from an inability to concentrate to severe psychosis</p> Signup and view all the answers

    What is the significance of a 24-hour urine-free cortisol level of 110 µg?

    <p>It confirms hypercortisolism</p> Signup and view all the answers

    What is the 5-year survival rate for patients with benign adrenal tumors after a successful adrenalectomy?

    <p>95%</p> Signup and view all the answers

    What is the rate of failure for surgery in patients with pituitary tumors?

    <p>20%</p> Signup and view all the answers

    What is the 2-year survival rate for patients with small cell lung carcinoma, a common ectopic source of ACTH hypersecretion?

    <p>20%</p> Signup and view all the answers

    What is the median survival time for patients with cortisol-secreting adrenal cancer?

    <p>7 months</p> Signup and view all the answers

    What is the recommended course of action for patients with ectopic ACTH-secreting tumors that cannot be resected?

    <p>Laparoscopic removal of both adrenal glands</p> Signup and view all the answers

    What is a potential side effect of metyrapone in females?

    <p>Masculinizing effects</p> Signup and view all the answers

    What is the effect of ketoconazole on cortisol synthesis?

    <p>Suppresses cortisol synthesis</p> Signup and view all the answers

    What is the typical finding on an MRI scan of the pituitary in patients with ACTH-dependent Cushing syndrome?

    <p>A small, benign tumor</p> Signup and view all the answers

    What is the characteristic laboratory finding in patients with ACTH-independent disease?

    <p>High serum cortisol levels but low serum ACTH concentrations</p> Signup and view all the answers

    What is the effect of the somatostatin analog octreotide on ACTH secretion?

    <p>Suppresses ACTH secretion in approximately one third of cases</p> Signup and view all the answers

    What is the diagnostic criterion for Cushing syndrome based on midnight serum cortisol levels?

    <p>A midnight serum cortisol level of 7.5 µg/dL or higher</p> Signup and view all the answers

    What is a common complication of Cushing syndrome?

    <p>Glucose intolerance</p> Signup and view all the answers

    What is the significance of adrenal hyperplasia in Cushing syndrome?

    <p>It is characterized by decreased ACTH, elevated cortisol, and elevated aldosterone levels</p> Signup and view all the answers

    What is a common sign of androgen excess in females with Cushing syndrome?

    <p>Amenorrhea</p> Signup and view all the answers

    What is the consequence of sudden discontinuation of corticosteroid in a patient with iatrogenic Cushing syndrome?

    <p>A life-threatening episode of acute adrenocortical insufficiency</p> Signup and view all the answers

    What is the outcome of slow tapering of corticosteroid doses in patients with iatrogenic Cushing syndrome?

    <p>Symptoms resolve and prognosis is excellent</p> Signup and view all the answers

    Study Notes

    Cushing's Syndrome

    • Cushing's syndrome is an endocrine disease characterized by excessive concentrations of circulating cortisol (hypercortisolism) with multiple etiologies.

    Prevalence

    • The single most common cause of Cushing's syndrome is the use of corticosteroid medications, affecting 12 cases per 1 million people.
    • The prevalence of hypercortisolism from all other causes combined is only 3 cases per 1 million people nationally.
    • The overall incidence is estimated as 2 new cases per 1 million persons per year.
    • Females are 8 times more likely than males to develop hypercortisolism from a pituitary tumor and three times more likely to develop a cortisol-secreting adrenal tumor.
    • 90% of all cases of Cushing's syndrome occur during adulthood.
    • The incidence of Cushing's syndrome in children is estimated at approximately 0.2 cases per 1 million persons per year.
    • The peak incidence of Cushing's syndrome due to adrenal or pituitary tumor occurs in persons 25 to 40 years of age.

    Significance

    • The significance of Cushing's syndrome lies primarily in the multitude of complications that can result from hypercortisolism.
    • Complications include bruising with minimal trauma, osteoporosis, moon-shaped face, stretch marks, hypertension, diabetes mellitus, and susceptibility to serious infections.

    Causes and Risk Factors

    • Causes of Cushing's syndrome are typically divided into two basic categories: ACTH-dependent and ACTH-independent.
    • The majority of cases diagnosed today are the result of administering supra-physiologic doses of corticosteroid drugs for various health conditions (e.g., autoimmune disease).
    • Common corticosteroids prescribed include prednisone, prednisolone, and methylprednisolone.
    • This type of Cushing's syndrome is often referred to as iatrogenic Cushing's syndrome and is a reversible form of the disorder.
    • Hypersecretion of ACTH by non-pituitary tumors (e.g., small cell lung carcinoma) is known as ectopic Cushing syndrome.
    • Hypersecretion of cortisol from either a benign or a cancerous tumor (carcinoma) of the adrenal gland.

    Signs and Symptoms

    • Back of the neck (so-called “buffalo hump”)
    • Truncal obesity
    • Increased blood glucose levels
    • Inhibition of both immune and inflammatory reactions that creates a susceptibility to infections
    • Cortisol specifically acts by decreasing T lymphocyte proliferation and suppressing the synthesis of important chemical mediators of inflammation.

    Diagnosis

    • An abnormally high 24-hour urine-free cortisol (110 µg) helps to confirm hypercortisolism.
    • If the patient’s morning serum cortisol is 2 µg/dL (by high-performance liquid chromatography) after receiving 1 mg dexamethasone orally late the previous evening, Cushing's syndrome can be ruled out with 98% certainty.
    • A midnight serum cortisol level 7.5 µg/dL or a midnight salivary cortisol level 550 ng/dL is highly suggestive of Cushing's syndrome.

    Diagnosis by Type

    • In patients with ACTH-DEPENDENT disease: serum ACTH, cortisol, and androgen concentrations are elevated.
    • In patients with ACTH-INDEPENDENT disease: serum cortisol levels are high but serum ACTH concentrations low, and serum aldosterone is normal.

    Prognosis

    • Varies from poor to excellent and also depends on the specific cause of hypercortisolism.
    • Since the patient with iatrogenic Cushing's syndrome often develops adrenal cortical atrophy with virtually no source of natural cortisol, sudden discontinuation of corticosteroid may result in a life-threatening episode of acute adrenocortical insufficiency characterized by shock.
    • Following a successful adrenalectomy, patients with a benign adrenal tumor have a 95% 5-year survival rate and a 90% 10-year survival rate.
    • Surgery for pituitary tumors may have a rate of failure as great as 20%, but if surgery is successful, the 5-year survival rate exceeds 90%.
    • The prognosis for patients with ectopic ACTH-secreting neoplasms depends on the specific type of tumor and its extent of spread.

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    Assess your knowledge of Cushing's syndrome, a rare endocrine disorder characterized by excessive cortisol levels, its causes, prevalence, and more.

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