Addison's Disease: Diagnosis and Clinical Features
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Questions and Answers

Which of the following is NOT a clinical feature of Addison's disease?

  • Weight gain (correct)
  • Hyperpigmentation
  • Gastrointestinal symptoms
  • Hypotension

    • Which diagnostic procedure involves administering 2mg of dexamethasone orally every six hours for 2 days?

  • 24hr urine for cortisol
  • High-dose dexamethasone suppression test (correct)
  • Serum electrolyte test
  • Plasma ACTH measurement

    • What does a high plasma ACTH level indicate?

  • Secondary Adrenocortical Insufficiency (Sheehan's syndrome)
  • Primary Adrenocortical Insufficiency (Addison's disease) (correct)
  • Congenital Adrenal Hyperplasia
  • Cushing's disease

    • Which of the following is NOT an aetiology of Addison's disease?

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

    Which of these is a symptom of Cushing's syndrome?

    <p>Round rose face</p> Signup and view all the answers

    Which test is used to diagnose Cushing's disease by measuring cortisol in urine?

    <p>24hr urine for cortisol</p> Signup and view all the answers

    What is the main hormone produced by the zona glomerulosa?

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

    Which part of the adrenal gland secretes epinephrine?

    <p>Adrenal medulla</p> Signup and view all the answers

    Which of the following stimulates the zona fasciculata to secrete its hormones?

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

    Which hormone contributes to libido and is a source of estrogen after menopause?

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

    Which hormone is mainly responsible for increasing blood levels of sodium and water?

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

    What is the primary function of glucocorticoids?

    <p>Stimulate protein breakdown</p> Signup and view all the answers

    Which structure is responsible for secreting catecholamines?

    <p>Adrenal medulla</p> Signup and view all the answers

    What is the role of mineralocorticoids in the body?

    <p>Regulate sodium and potassium levels</p> Signup and view all the answers

    Which zone of the adrenal cortex secretes androgens?

    <p>Zona reticularis</p> Signup and view all the answers

    Which gland is anatomically closest to the adrenal gland?

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

    Which hormone regulates blood volume, blood pressure, and levels of sodium, potassium, and hydrogenate in the blood?

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

    What enzyme is involved in the conversion of cholesterol to pregnenolone?

    <p>17β-hydroxylase</p> Signup and view all the answers

    What is the role of CRH in the hypothalamic-pituitary-adrenal axis?

    <p>To stimulate the release of ACTH</p> Signup and view all the answers

    Which of the following is NOT a precursor to estrogen in adrenal and gonadal steroidogenesis?

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

    Which condition is characterized by primary hypercortisolaemia?

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

    Which phase of hypocortisolaemia involves both glucocorticoid and mineralocorticoid deficiency?

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

    Which hormone stimulates the synthesis of cortisol and other corticosteroids?

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

    What is the impact of increased ACTH levels on the body?

    <p>Increased pigmentation of mucous membranes and other areas</p> Signup and view all the answers

    Study Notes

    Adrenal Gland Structure and Function

    • The adrenal gland has two main parts: the suprarenal cortex and the suprarenal medulla
    • The suprarenal cortex secretes steroid hormones essential for life, while the suprarenal medulla secretes norepinephrine and epinephrine

    Adrenal Gland Cell Types and Hormones

    • The suprarenal cortex has three zones: zona glomerulosa, zona fasciculata, and zona reticularis
    • The zona glomerulosa produces mineralocorticoids (mainly aldosterone), zona fasciculata produces glucocorticoids (mainly cortisol), and zona reticularis produces sex corticoids
    • The suprarenal medulla produces catecholamines (epinephrine and norepinephrine)

    Adrenal Cortex Hormones

    • Mineralocorticoids:
      • Produced by zona glomerulosa
      • Stimulated by increased blood K+ level and angiotensin II
      • Principal action: increases blood level of Na+ and water, and increases blood level of K+
    • Glucocorticoids:
      • Produced by zona fasciculata and zona reticularis
      • Stimulated by ACTH and circadian rhythm
      • Principal action: influences protein breakdown, stimulates gluconeogenesis, suppresses inflammation, and depresses immune response
    • Androgens:
      • Produced by zona reticularis
      • Stimulated by ACTH
      • Principal action: contributes to growth of axillary and pubic hair, and contributes to libido and sources of estrogen after menopause

    Adrenal Medulla Hormones

    • Epinephrine and norepinephrine:
      • Produced by adrenal medulla
      • Stimulated by sympathetic preganglionic neurons
      • Principal action: enhances effects of sympathetic part of autonomic nervous system during stress

    Hypothalamic-Pituitary-Adrenal Axis

    • Corticotropin-Releasing Hormone (CRH):
      • 41 amino acids
      • Transmitted by the hypophyseal portal vessels to the Adenohypophysis
      • Stimulates ACTH release
    • Adrenocorticotrophic Hormone (ACTH):
      • 39 amino acids, 4.5kDa
      • Found free in the plasma, life of a few minutes
      • Stimulates synthesis of cortisol and other corticosteroids

    Addison's Disease

    • Caused by autoimmune destruction of the adrenal cortex
    • Aetiology: autoimmunity, tuberculosis, secondary depositions (sarcoidosis, amyloidosis, hemochromatosis)
    • Clinical features: gastrointestinal symptoms, hyperpigmentation, weight loss, general tiredness, hypotension, vitiligo, acute abdominal crises, muscle weakness, vomiting, diarrhea, and sweating

    Cushing's Syndrome

    • Caused by hypersecretion of cortisol
    • Discovered in 1932
    • Symptoms: obesity, round rose face, and others associated with prolonged exposure to high levels of cortisol
    • Diagnosis: 24hr urine for cortisol, and other tests

    Regulation of Aldosterone Secretion

    • Regulated by the renin-angiotensin-aldosterone pathway
    • Stimulated by increased blood K+ level and angiotensin II

    Disorders of the Adrenal Cortex

    • Hypocortisolaemia:
      • Primary: Addison's disease
      • Secondary: hypothalamic or pituitary
    • Hypercortisolaemia:
      • Primary: Cushing's syndrome
      • Secondary: Cushing's disease

    Negative Feedback Regulation of Glucocorticoid Secretion

    • High level of CRH and low level of glucocorticoids promote release of ACTH, which stimulates glucocorticoid secretion by the suprarenal cortex

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    Description

    This quiz covers the causes, symptoms, and diagnosis of Addison's disease, a cortisol deficiency disorder. Topics include etiology, clinical features, and diagnostic procedures.

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