Adrenal cortex applied physiology
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This document discusses adrenal cortex function and disorders. It covers three types of hypersecretion: Cushing's syndrome caused by excess cortisol leading to characteristic fat distribution and signs; hyperaldosteronism caused by excess aldosterone leading to hypertension and hypokalemia; and adrenogenital syndrome caused by excess androgens leading to masculinization in females. It also discusses two types of hyposecretion: Addison's disease caused by cortisol and aldosterone deficiency with pigmentation and weakness; and congenital adrenal hyperplasia caused by enzyme deficiencies leading to androgen excess and sexual abnormalities.
Adrenal cortex applied physiology
- 1. Adrenal Cortex (Applied Physiology) DANISH HASSAN LECTURER, UNIVERSITY OF SARGODHA
- 2. Adrenal Cortex Hyper-secretion 1. Cushing syndrome 2. Hyper-aldosteronism 3. Adrenogenital Syndrome Hypo-secretion 1. Addison disease / Chronic adrenal insufficiency 2. Congenital Adrenal Hyperplasia
- 3. Adrenal Cortex (Hyperactivity) DANISH HASSAN LECTURER, UNIVERSITY OF SARGODHA
- 4. 1. Cushing Syndrome ļµ Cushing syndrome is a disorder characterized by obesity OR ļµ Cushing's syndrome describes the signs and symptoms associated with prolonged exposure to inappropriately high levels of the hormone cortisol. ļµ This can be caused by taking glucocorticoid drugs, or diseases that result in excess cortisol, (ACTH), or CRH levels
- 5. ļµ Causes ļµ Hypersecretion of glucocorticoids, particularly cortisol. ļµ It may be either due: 1. Pituitary origin (Cushing Disease) 2. Adrenal origin (Cushing Syndrome)
- 6. ļµ Pituitary Origin ļµ Increased secretion of ACTH causes hyperplasia of adrenal cortex, leading to hypersecretion of glucocorticoid. ļµ ACTH secretion is increased by: 1. Tumor in pituitary cells, particularly in basophilic cells which secrete ACTH 2. Malignant tumor of non-endocrine origin like cancer of lungs or abdominal viscera 3. Hypothalamic disorder causing hypersecretion of corticotropin-releasing hormone.
- 7. ļµ Adrenal Origin ļµ Cortisol secretion is increased by: 1. Tumor in zona fasciculata of adrenal cortex 2. Carcinoma of adrenal cortex 3. Prolonged treatment of chronic inflammatory diseases like rheumatoid arthritis, with high dose of exogenous glucocorticoids 4. Prolonged treatment with high dose of ACTH, which stimulates adrenal cortex to secrete excess glucocorticoids
- 8. ļµ Recently, Cushing syndrome is classified into two types: ļµ ACTH-dependent Cushing syndrome ļµ Due to hypersecretion of ACTH
- 9. ļµ ACTH-independent Cushing syndrome ļµ The syndrome develops due to abnormal membrane receptors for some peptides like interleukin-1, gonadotropin-releasing hormone and gastric inhibitory polypeptide in the cells of zona fasciculata. ļµ The binding of these peptides to the abnormal receptors increases secretion of glucocorticoids, resulting in Cushing syndrome. ļµ Cushing syndrome that is developed by treatment with exogenous glucocorticoids also belongs to this type
- 10. ļµ Signs and Symptoms 1. Characteristic feature of this disease is the disproportionate distribution of body fat, resulting in some abnormal features: 1. Moon face: The edematous facial appearance due to fat accumulation and retention of water and salt 2. Torso: Fat accumulation in the chest and abdomen. Arms and legs are very slim in proportion to torso 3. Buffalo hump: Due to fat deposit on the back of neck and shoulder 4. Pot belly: Due to fat accumulation in upper abdomen
- 14. 5. Purple Striae: Reddish purple stripes on abdomen due to three reasons: 1. Stretching of abdominal wall by excess subcutaneous fat 2. Rupture of subdermal tissues due to stretching 3. Deficiency of collagen fibers due to protein depletion 6. Thinning of extremities due to protein depletion caused by increased catabolism of proteins
- 16. 7. Aconthosis: Skin disease characterized by darkened skin patches in certain areas such as axilla, neck and groin
- 17. 8. Pigmentation of skin, especially in ACTHdependent type due to hypersecretion of ACTH which has got melanocyte-stimulating effect 9. Facial plethora: Facial redness 10. Hirsutism: Heavy growth of body and facial hair 11. Weakening of muscles because of protein depletion 12. Bone resorption and osteoporosis due to protein depletion
- 18. 13. Hyperglycemia due to gluconeogenesis (from proteins) and inhibition of peripheral utilization of glucose leading to glucosuria and adrenal diabetes 14. Hypertension by the mineralocorticoid effects of glucocorticoids ā retention of sodium and water results in increase in ECF volume and blood volume, leading to hypertension 15. Immunosuppression resulting in susceptibility for infection 16. Poor wound healing
- 19. ļµ Tests for Cushing Syndrome ļµ Observation of external features ļµ Determination of blood sugar and cortisol levels ļµ Analysis of urine for 17-hydroxysteroids.
- 20. ļµ Treatment for Cushing Syndrome ļµ Depends upon the cause of the disease. ļµ Treatment may include cortisol-inhibiting drugs, surgical removal of pituitary or adrenal tumor, radiation or chemotherapy. ļµ Drugs that block steroidogenesis, such as metyrapone, ketoconazole, and aminoglutethimide, or that inhibit ACTH secretion, such as serotonin antagonists and GABAtransaminase inhibitors, can also be used when surgery is not feasible.
- 21. ļµ Nelson Syndrome ļµ It is the rapid enlargement of a pituitary adenoma that occurs after the removal of both adrenal gland. OR ļµ A disorder that develops after surgical removal of both adrenal glands. ļµ It is because of the growth of pituitary tumor that secretes excess ACTH.
- 22. ļµ The features include headache and visual problems. ļµ Nelson syndrome can be treated with radiation or surgical removal of the pituitary gland
- 23. 2. Hyper-Aldosteronism ļµ Increased secretion of aldosterone is called hyperaldosteronism.
- 24. ļµ Causes and Types ļµ Depending upon the causes hyperaldosteronism is classified into two types: 1. Primary hyperaldosteronism 2. Secondary hyperaldosteronism
- 25. ļµ Primary Hyperaldosteronism ļµ Also known as Conn syndrome. ļµ It develops due to tumor in zona glomerulosa of adrenal cortex. ļµ In primary hyperaldosteronism, edema does not occur because of escape phenomenon
- 26. ļµ Secondary Hyperaldosteronism ļµ Also called Hyperreninism or Hyperreninimic aldosteronism. ļµ Secondary hyperaldosteronism occurs due to extra adrenal causes such as: ļµ Congestive Cardiac failure ļµ Nephrosis ļµ Toxemia of pregnancy ļµ Cirrhosis of liver.
- 27. ļµ Signs and Symptoms 1. Increase in ECF volume and blood volume 2. Hypertension due to increase in ECF volume and blood volume 3. Severe depletion of potassium, which causes renal damage. 4. The kidneys fail to produce concentrated urine. It leads to polyuria and polydipsia
- 28. 5. Muscular weakness due to potassium depletion 6. Metabolic alkalosis due to secretion of large amount of hydrogen ions into the renal tubules. 7. Metabolic alkalosis reduces blood calcium level causing tetany.
- 29. ļµ Test for Hyperaldosteronism: ļµ One of the diagnostic criteria of primary aldosteronism is a decreased plasma renin concentration. ļµ This results from feedback suppression of renin secretion caused by the excess aldosterone or by the excess extracellular fluid volume and arterial pressure resulting from the aldosteronism.
- 30. ļ½ Treatment ļ½ Treatment of primary aldosteronism may include surgical removal of the tumor or of most of the adrenal tissue when hyperplasia is the cause. ļ½ Another option for treatment is pharmacological antagonism of the mineralocorticoid receptor with spironolactone or eplerenone.
- 31. 3. Adrenogenital Syndrome ļµ Under normal conditions, adrenal cortex secretes small quantities of androgens which do not have any significant effect on sex organs or sexual function. ļµ However, secretion of abnormal quantities of adrenal androgens develops adrenogenital syndrome. ļµ Testosterone is responsible for the androgenic activity in adrenogenital syndrome
- 32. ļµ Causes ļµ Tumor of zona reticularis in adrenal cortex
- 33. ļµ Symptoms ļµ Characterized by the tendency for the development of secondary sexual character of opposite sex.
- 34. ļµ Symptoms in females ļµ Increased secretion of androgens causes development of male secondary sexual characters. ļµ The condition is called adrenal virilism. ļµ Symptoms are: ļµ Masculinization due to increased muscular growth ļµ Deepening of voice ļµ Amenorrhea ļµ Male type of hair growth.
- 35. ļµ Symptoms in Males: ļµ Sometimes, the tumor of estrogen secreting cells produces more than normal quantity of estrogens in males. ļµ It produces some symptoms such as: ļµ Feminization ļµ Gynecomastia (enlargement of breast) ļµ Atrophy of testis ļµ Loss of interest in women
- 36. Adrenal Cortex (Hypo activity) DANISH HASSAN LECTURER, UNIVERSITY OF SARGODHA
- 37. Addison Disease/Chronic Adrenal Insufficiency ļµ Addison disease is the failure of adrenal cortex to secrete corticosteroids.
- 38. ļµ Types of Addison Disease ļµ Primary Addison disease due to adrenal cause ļµ Secondary Addison disease due to failure of anterior pituitary to secrete ACTH ļµ Tertiary Addison disease due failure of hypothalamus to secrete corticotropin-releasing factor (CRF).
- 39. ļµ Causes for Primary Addison Disease ļµ Atrophy of adrenal cortex due to autoimmune diseases ļµ Destruction of the gland because of tuberculosis ļµ Destruction of hormone-secreting cells in adrenal cortex by malignant tissues ļµ Congenital failure to secrete cortisol ļµ Adrenalectomy and failure to take hormone therapy.
- 40. ļµ Signs and Symptoms ļµ Signs and symptoms develop in Addison disease because of deficiency of both cortisol and aldosterone. ļµ Common signs and symptom are: 1. Pigmentation of skin and mucous membrane due to excess ACTH secretion, induced by cortisol deficiency. 2. Muscular weakness 3. Dehydration with loss of sodium
- 41. 4. Hypotension 5. Decreased cardiac output and decreased workload of the heart, leading to decrease in size of the heart 6. Hypoglycemia 7. Nausea, vomiting and diarrhea. Prolonged vomiting and diarrhea cause dehydration and loss of body weight 8. Susceptibility to any type of infection 9. Inability to withstand any stress, resulting in Addisonian crisis.
- 42. ļµ Tests for Addison Disease ļµ Measurement of blood level of cortisol and Aldosterone ļµ Measurement of amount of steroids excreted in urine
- 43. ļµ Addisonian Crisis or Adrenal Crisis or Acute Adrenal Insufficiency ļµ Adrenal crisis is a common symptom of Addison disease, characterized by sudden collapse associated with an increase in need for large quantities of glucocorticoids. ļµ The condition becomes fatal if not treated in time.
- 44. ļµ It is caused by: 1. Exposure to even mild stress 2. Hypoglycemia due to fasting 3. Trauma 4. Surgical operation 5. Sudden withdrawal of glucocorticoid treatment
- 45. 2. Congenital Adrenal Hyperplasia ļµ A congenital disorder, characterized by increase in size of adrenal cortex. ļµ Size increases due to abnormal increase in the number of steroid-secreting cortical cells
- 46. ļµ Causes ļµ Even though the size of the gland increases, cortisol secretion decreases. ļµ It is because of the congenital deficiency of the enzymes necessary for the synthesis of cortisol, particularly, 21-hydroxylase. ļµ Lack of this enzyme reduces the synthesis of cortisol, resulting in ACTH secretion from pituitary by feedback mechanism. ACTH stimulates the adrenal cortex causing hyperplasia, with accumulation of lipid droplets.
- 47. ļµ Hence, it is also called congenital lipid adrenal hyperplasia. ļµ Cortisol cannot be synthesized because of lack of 21-hydroxylase. ļµ Therefore, due to the constant simulation of adrenal cortex by ACTH, the secretion of androgens increases. ļµ It results in sexual abnormalities such as virilism
- 48. ļµ Symptoms ļµ In boys ļµ Adrenal hyperplasia produces a condition known as macrogenitosomia praecox ļµ Features of macrogenitosomia praecox: ļµ Precocious body growth, causing stocky appearance called infant Hercules ļµ Precocious sexual development with enlarged penis even at the age of 4 years.
- 49. ļµ In girls ļµ In girls, adrenal hyperplasia produces masculinization. ļµ It is otherwise called virilism. ļµ In some cases of genetic disorders, the female child is born with external genitalia of male type. ļµ This condition is called pseudo hermaphroditism.