Cushing's Syndrome Overview
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Questions and Answers

What is the most common cause of Cushing's syndrome?

  • Adrenal cortical adenomas and carcinomas
  • Pituitary hypersecretion of ACTH
  • Iatrogenic use of topical and inhaled glucocorticoids (correct)
  • Ectopic ACTH secretion by non-pituitary tumors

    • Which of the following is NOT a characteristic of ACTH-dependent Cushing's syndrome?

  • Bilateral adrenal cortical hyperplasia
  • Ectopic secretion of corticotropin-releasing hormone (CRH)
  • Iatrogenic or factitious Cushing's syndrome due to exogenous ACTH administration
  • Increased cortisol levels (correct)

    • What is the most common cause of ACTH-independent Cushing's syndrome?

  • Adrenal cortical adenomas and carcinomas
  • Primary pigmented nodular adrenal cortical disease
  • Bilateral macronodular adrenal hyperplasia
  • Iatrogenic or factitious Cushing's syndrome (correct)

    • What is the purpose of the dexamethasone suppression test in diagnosing Cushing's syndrome?

    <p>To evaluate the feedback mechanism of the hypothalamic-pituitary-adrenal axis (D)</p> Signup and view all the answers

    Which of the following statements is TRUE about the dexamethasone suppression test?

    <p>High-dose dexamethasone suppresses ACTH and cortisol in patients with pituitary Cushing's (D)</p> Signup and view all the answers

    Which of the following is NOT a typical characteristic of Cushing's syndrome?

    <p>Decreased ACTH levels (C)</p> Signup and view all the answers

    Which of the following conditions can lead to the development of Cushing's syndrome?

    <p>Ectopic ACTH secretion (A)</p> Signup and view all the answers

    What is the most common type of ACTH-dependent Cushing's syndrome?

    <p>Cushing's disease (C)</p> Signup and view all the answers

    Which of the following symptoms is least common in individuals with Cushing's syndrome?

    <p>Proximal muscle weakness (C)</p> Signup and view all the answers

    What is the primary goal of treatment for Cushing's syndrome?

    <p>All of the above (D)</p> Signup and view all the answers

    In the management of Cushing's disease, which treatment option is considered second-line for patients not cured by pituitary surgery?

    <p>Pituitary eradication (C)</p> Signup and view all the answers

    Which of the following contribute to the characteristic round face appearance in Cushing's syndrome?

    <p>Fluid retention due to mineralocorticoid excess (B)</p> Signup and view all the answers

    Which treatment option is primarily used for ACTH-independent Cushing's syndrome?

    <p>Bilateral adrenalectomy (D)</p> Signup and view all the answers

    What is the expected long-term prognosis for patients with Cushing's syndrome who have successfully undergone treatment and achieved remission?

    <p>Good, but patients may experience long-term health complications (D)</p> Signup and view all the answers

    Which of the following is NOT a consequence of elevated cortisol levels?

    <p>Increased bone formation (B)</p> Signup and view all the answers

    Which of the following is a potential complication of long-term Cushing's syndrome?

    <p>Cardiovascular disease (B)</p> Signup and view all the answers

    Flashcards

    Functions of Cortisol

    Cortisol helps reduce inflammation, maintain blood pressure, and increases energy production from fats and proteins.

    Anti-inflammatory function

    Cortisol's role in reducing inflammation and suppressing immune response.

    Signs of Cushing's syndrome

    Common symptoms include obesity, round face, and decreased libido due to excessive cortisol.

    Common symptoms of Cushing's syndrome

    Symptoms like obesity, hirsutism, and hypertension indicating excess cortisol levels.

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    Primary treatment goals

    To normalize cortisol levels, remove tumors, and avoid long-term medication dependency.

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    Cushing's disease management

    Involves pituitary surgery, medical therapy, or adrenal enzyme inhibitors based on disease type.

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    Prognosis after treatment

    Physical symptoms may resolve over months, but quality of life may remain affected long-term.

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    ACTH-independent Cushing's syndrome

    Definitive treatment is bilateral adrenalectomy for adrenal tumors; medications for ectopic tumors.

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    Cushing's Syndrome

    A condition caused by prolonged excess of glucocorticoids.

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    Iatrogenic Cause

    Most common cause of Cushing's syndrome from medical treatment.

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    ACTH-dependent Cushing's

    Cushing's syndrome associated with elevated ACTH levels.

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    Cushing's Disease

    The most common ACTH-dependent Cushing's caused by pituitary tumor.

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    Ectopic ACTH secretion

    ACTH produced by non-pituitary tumors causing Cushing's.

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    Dexamethasone suppression test

    Test used to diagnose Cushing's syndrome through response to dexamethasone.

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    24-hour urinary free cortisol

    Elevated levels indicate Cushing's syndrome.

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    ACTH-independent Cushing's

    Cushing's syndrome not caused by ACTH, often due to adrenal tumors.

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    Study Notes

    Cushing's Syndrome

    • Cushing's syndrome is caused by prolonged excess circulating glucocorticoids.
    • The most common cause is iatrogenic due to the use of topical and inhaled glucocorticoids.
    • Cushing's syndrome is categorized into ACTH-dependent and ACTH-independent types.

    ACTH-Dependent Cushing's Syndrome

    • Associated with bilateral adrenal cortical hyperplasia.
    • Cushing's disease is the most frequent cause (65-70% of cases), resulting from pituitary hypersecretion of ACTH.
    • Ectopic ACTH secretion by non-pituitary tumors accounts for 10-15% of cases.
    • Ectopic secretion of corticotropin-releasing hormone (CRH) by non-hypothalamic tumors, causing pituitary hypersecretion of ACTH, occurs in less than 1% of cases.
    • Iatrogenic or factitious Cushing's syndrome due to exogenous ACTH administration is rare (< 1%).

    ACTH-Independent Cushing's Syndrome

    • Iatrogenic or factitious Cushing's syndrome is the most common cause.
    • Adrenal cortical adenomas and carcinomas account for 18-20% of cases.
    • Primary pigmented nodular adrenal cortical disease (also known as bilateral adrenal micronodular hyperplasia) is rare (< 1%).
    • Bilateral macronodular adrenal hyperplasia is also rare (< 1%).

    Diagnosis

    • Dexamethasone suppression test determines the cause of Cushing's syndrome.
    • Dexamethasone is a powerful corticosteroid influencing the body's feedback system.
    • Normal individuals show ACTH and cortisol reduction after low-dose dexamethasone.
    • Patients with pituitary Cushing's syndrome do not suppress ACTH and cortisol levels with low-dose dexamethasone.
    • High-dose dexamethasone suppresses ACTH and cortisol in pituitary Cushing's patients.
    • High-dose dexamethasone does not suppress ACTH or cortisol in patients with ectopic ACTH production, since only pituitary ACTH responds to feedback.
    • Elevated cortisol levels are a key indicator of Cushing's syndrome.
    • Increased 24-hour urinary free cortisol level also suggests Cushing's syndrome.

    Functions of Cortisol

    • Anti-inflammatory
    • Maintains blood pressure
    • Increases gluconeogenesis, lipolysis, and proteolysis
    • Decreases immune function
    • Decreases bone formation

    Signs and Symptoms

    • Common signs and symptoms:
      • Decreased libido
      • Obesity or weight gain
      • Plethora (ruddy complexion)
      • Round face
      • Hirsutism
      • Menstrual irregularities
      • Hypertension
      • Ecchymosis
      • Lethargy or depression
      • Dorsal fat pad
      • Abnormal glucose tolerance
    • Less common signs and symptoms:
      • ECG abnormalities or atherosclerosis
      • Striae
      • Edema
      • Proximal muscle weakness
      • Osteopenia or fracture
      • Headache
      • Backache
      • Recurrent infections
      • Abdominal pain
      • Acne
      • Female balding

    Management

    • Goals of treatment:
      • Restore normal cortisol levels to alleviate clinical manifestations.
      • Eliminate tumors that threaten health.
      • Avoid long-term dependence on medication.
      • Prevent permanent hormone deficiency.
    • Optimal treatment:
      • Locate and completely remove corticotropin-secreting pituitary or ectopic tumors, or cortisol-secreting adrenal tumors.
    • For Cushing's disease not cured by surgery:
      • Medical therapy targeting the corticotropic tumor (cabergoline or pasireotide) can normalize 24-hour urinary free cortisol in 20-40%, mainly in mild hypercortisolism.
      • Pituitary eradication is a second-line approach for persistent or recurrent Cushing's disease.
    • For ACTH-dependent Cushing's syndrome:
      • Adrenal enzyme inhibitors manage hypercortisolism until radiation therapy (RT) is effective.
      • Conventional RT corrects hypercortisolism in up to 85% of adults after tumor debulking.
    • For ACTH-independent Cushing's syndrome:
      • Total bilateral adrenalectomy is the definitive treatment for ACTH-producing ectopic tumors.
      • Metastatic or occult ectopic ACTH tumors may respond to somatostatin analogs, adrenal enzyme inhibitors, or mitotane.

    Prognosis

    • Physical symptoms and signs gradually resolve within 2-12 months following effective treatment.
    • Hypertension, osteoporosis, and glucose intolerance can improve but may not fully resolve.
    • Patients may experience long-term quality-of-life issues despite remission.
    • Long-term prognosis for benign diseases is excellent once cured.
    • Prognosis for malignant cases varies, depending on hypercortisolism control and cancer handling.

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    Description

    This quiz explores the causes and types of Cushing's syndrome, focusing on ACTH-dependent and ACTH-independent categories. It covers key concepts such as Cushing's disease, adrenal hyperplasia, and the role of glucocorticoids. Test your knowledge on this important endocrine disorder!

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