Lect 1-pituitary insufficiency

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pituitary insufficiency

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Lect 1-pituitary insufficiency

  1. 1. Pituitary Gland Diseases SMS ????? Dr. Mohanad R. Alwan
  2. 2. Pituitary Gland <ul><li>Weight 600 mg </li></ul><ul><li>Is located within the bony cavity (sella turcica) </li></ul><ul><li>Anatomically and functionally distinct anterior and posterior lobes </li></ul><ul><li>Anterior Pituitary-adenohypophysis </li></ul><ul><li>Posterior pituitary-neurohypophysis </li></ul>
  3. 3. <ul><li>Adrenocorticotropic hormone(ACTH) </li></ul><ul><li>Thyroid-stimulating hormone(TSH) </li></ul><ul><li>Growth hormone, Prolactin </li></ul><ul><li>Luteinizing hormone, </li></ul><ul><li>Follicle stimulating hormone </li></ul><ul><li>melanocyte–stimulating hormones </li></ul><ul><li>Oxytocin, </li></ul><ul><li>Antidiuretic hormone </li></ul>
  4. 4. Pituitary Development <ul><li>The pituitary originate from different source. </li></ul><ul><li>The anterior pituitary from Rathke´s pouch ( which is an embryonic invagination of the pharyngeal epithelium ). </li></ul><ul><li>The posterior pituitary from an outgrow of the hypothalamus . </li></ul>
  5. 5. Hypothalamic <ul><li>Hypothalamic neural ce l ls synthesize specific releasing and inhibiting hormones that are secreted directly into the portal vessels of the pituitary stalk. </li></ul><ul><li>Hypothalamic-pituitary portal plexus provides the major blood source for the anterior pituitary. </li></ul>
  6. 6. Hypothalamic releasing hormones Hypothalamic releasing hormone Effect on pituitary Corticotropin releasing hormone (CRH) Stimulates ACTH secretion Thyrotropin releasing hormone (TRH) Stimulates TSH and Prolactin secretion Growth hormone releasing hormone (GHRH) Stimulates GH secretion Somatostatin Inhibits GH (and other hormone) secretion Gonadotropin releasing hormone (GnRH) a.k.a LHRH Stimulates LH and FSH secretion Prolactin releasing hormone (PRH) Stimulates PRL secretion Prolactin inhibiting hormone (dopamine) Inhibits PRL secretion
  7. 7. Hypothalamic -Pituitary communication
  8. 9. Anterior Pituitary <ul><li>Is often referred to as the “MASTER GLAND” because, it orchestrates the complex regulatory functions of multiple other endocrine glands. </li></ul>
  9. 10. Produces six major hormones: <ul><li>Prolactin (PRL) </li></ul><ul><li>Growth hormone (GH) </li></ul><ul><li>Adrenoicorticotropin hormone (ACTH) </li></ul><ul><li>Luteinizing hormone (LH) </li></ul><ul><li>Follicle-stimulating hormone (FSH) </li></ul><ul><li>Thyroid-stimulating hormone (TSH) </li></ul>
  10. 12. Anterior Pituitary Insufficiency
  11. 13. Etiology <ul><li>Reduced pituitary function can result from inhereited disorders; more commonly, </li></ul><ul><li>it is acquired and reflects the mass effects of tumors or the consequences of inflamation or vascular damage. </li></ul>
  12. 14. Causes of hypopituitarism <ul><li>Tumours (tu’) </li></ul><ul><li>Pituitary tumor </li></ul><ul><li>Adenoma,craniopharyngioma </li></ul><ul><li>Cerebral tumor </li></ul><ul><li>Hypothalamic disorders </li></ul><ul><li>Tumor </li></ul><ul><li>Functional disturbance- </li></ul><ul><li>Eg -Anorexia nervosa </li></ul><ul><li>Isolated GH and GnH secretion due to impaired secretion of hypothalamic releasing hormones </li></ul><ul><li>Miscellaneous </li></ul><ul><li>Sarcoidosis ( inflammation of L.N) </li></ul><ul><li>Histocytosis X ( abnormal increase in the number of immune cells ) </li></ul><ul><li>Haemochromatosis </li></ul><ul><li>Vascular ds </li></ul><ul><li>Necrosis (Sheehan’s synd) </li></ul><ul><li>Infarction </li></ul><ul><li>Severe hypotension </li></ul><ul><li>Cranial arteritis </li></ul><ul><li>Trauma </li></ul><ul><li>Infection </li></ul><ul><li>Meningitis esp TB, syphilis </li></ul><ul><li>Iatrogenic </li></ul><ul><li>Surgery </li></ul><ul><li>Irradiation </li></ul><ul><li>Prolonged rx with glucocorticoid or thyroid hormones-isolated ACTH or TSH suppression </li></ul>
  13. 15. Developmental and Genetic Causes of Hypopituitarism <ul><li>Pituitary Displasia </li></ul><ul><li>Tissue-Specific Factor Mutations </li></ul><ul><li>Developmental Hypotalamic Dysfunction: </li></ul><ul><ul><li>Kallmann Syndrome ( Hypogonadotropic hypogonadism) </li></ul></ul><ul><ul><li>Laurence-Moon-Bardet-Biedl Syndrome ( involves many body systems) </li></ul></ul><ul><ul><li>Fröhlich Syndrome ( childhood metabolicdisorder) </li></ul></ul><ul><ul><li>Prader-Willi Syndrome. </li></ul></ul>
  14. 16. Acquired Hypopituitarism <ul><li>Trauma. </li></ul><ul><li>Vascular </li></ul><ul><li>Pituitary or hypothalamic neoplasms </li></ul><ul><li>Inflammatory diseases. </li></ul><ul><li>Infiltrative disorders such as sarcoidosis, hemochromatosis. </li></ul>
  15. 17. ANTERIOR PITUITARY HYPOFUNCTION (hypopituitarism) <ul><li>3 most common causes: </li></ul><ul><li>Non secretory adenoma of ant pituitary </li></ul><ul><li>Sheehan’s syndrome ( postpartum pituitary necrosis) </li></ul><ul><li>Empty sella syndrome ( pituitary gland become shrinks or becomes flattened) </li></ul>
  16. 18. <ul><li>Partial hypopituitarism is more frequent than complete loss of pit functions </li></ul><ul><li>Sx/signs do not manifest until > 75% of ant lobe is destroyed </li></ul><ul><li>GH secretion is an early feature of pit failure-effects > dramatic in children but less significant in adults </li></ul><ul><li>LH/ FSH are affected before ACTH </li></ul><ul><li>Hypothyroidism is an uncommon presenting feature of pit failure </li></ul>
  17. 19. Clinical features Hormone Features of deficiency GH Children: growth retardation Adults: ↓muscle bulk Tendency to hypoglycaemia. Prolactin Failure of lactation Gonadotrophins Children: delayed puberty Female: oligomenorrhoea, infertility,atrophy of breast & genitalia Male:Impotence,azoospermia,testicular atrophy Both sexes: LO libido,LO body hair ACTH Weight loss, hypotension, hypoglycaemia, decrease skin pigmentation TSH Weight gain, cold intolerence,fatique Vasopressin Thirst, polyuria
  18. 20. Posterior Pituitary hypofunction Causes <ul><li> ADH production  cranial diabetes insipidus </li></ul><ul><li>(DI) </li></ul><ul><li>Causes of cranial DI </li></ul><ul><li>Tumours-craniopharyngioma, secondary tumours (metastatic CA), pituitary tumours with suprasella extension. </li></ul><ul><li>Granulomatous disease. </li></ul><ul><li>Meningitis, abscess and encephalitis. </li></ul><ul><li>Vascular disorders. </li></ul><ul><li>Trauma. </li></ul><ul><li>Surgery. </li></ul><ul><li>Idiopathic. </li></ul>
  19. 21. Posterior Pituitary hypofunction Effects <ul><li>Polyuria-uncontrolled renal water excretion, tendency to dehydration </li></ul><ul><li>Polydipsia-excessive thirst, dehydration stimulate thirst centre resulting in increase water intake </li></ul>
  20. 22. PITUITARY HYPERFUNCTION (HYPERPITUITARISM) <ul><li>Causes </li></ul><ul><li>Pituitary adenoma </li></ul><ul><li>Carcinoma (rare) </li></ul><ul><li>Hypothalamic disorder-excess stimulation of the pituitary (rare) </li></ul><ul><li>Order of frequency with which hormone secretion occurs in pituitary tumour is prolactin (relatively common)  GH  ACTH  gonadotrophin  TSH </li></ul>Hyperpituitarism - excessive production of adenohypoph y s eal hormones
  21. 23. PITUITARY HYPERFUNCTION (HYPERPITUITARISM) Prolactin excess Hyperprolactinaemia GH excess Acromegaly/ gigantism ACTH excess Cushing’s disease TSH excess (rare) Secondary hyperthyroidism Gonadotrophin excess menstrual disorders and infertillity
  22. 24. Consequences: <ul><li>Excessive Secretion of prolactin   secretion of GnRH  </li></ul><ul><li>  gonadotrophins </li></ul>In men: impotency, decreased libido In women: amenorrhea, galactorrhea b) Excessive Secretion of somatotrophine (growth hormone )  acromegaly (in adults)  gigantism (in adolescents whose epiphyseal plates have not yet closed)
  23. 25. b)-continuing Pathomechanisms involved : <ul><li>The usual GH baseline secretion pattern is lost (as are sleep – related GH </li></ul><ul><li>peaks) </li></ul>- A totally unpredictable secretory pattern of GH occurs <ul><li>GH secretion is slightly elevated   somatomedin  stimulation of growth </li></ul><ul><li>(in adolescent) </li></ul>- C onnective tissue proliferation - B ony proliferation  characteristic appearance of acromegaly -  P hosphate reabsorbtion in renal tubules  hyperphosphatemia - I mpairement of carbohydrate tolerance -  M etabolic rate <ul><li>H yperglycemia - it is a result of GH inhibition of peripheral glucose uptake </li></ul><ul><li>and increase hepatic glucose production  compensatory hyperinsulinism  </li></ul><ul><li> insulin resistance  diabetes mellitus </li></ul>In adult s :
  24. 26. c) Excessive Secretion of corticotrophin ( ACTH)  central form of Cushing syndrome (Cushing disease) Causes: micro- or macroadenomas of adenohypoph y sis, hypothalamic disorders Pathophysiology: C hronic hypercortisolism is the main disturbance of  ACTH Symptoms and signs: <ul><li>weight gain: - accumulation of adipose tissue in the trunk, facial, and </li></ul><ul><li>cervical areas (truncal obesity, moon face, buffalo hump) </li></ul><ul><li>- weight gain from Na and water retention </li></ul> glucose intolerance  DM type 2  polyuria: osmotic polyuria due to glycosuria
  25. 27. <ul><li>Protein Wasting : due to catabolic effects of cortisol on peripheral tissue </li></ul><ul><li>(muscle wasting  muscle atrophy and weakness  thin lower </li></ul><ul><li>extremities ) </li></ul> in bone: - loss of protein matrix  osteoporosis -  blood calcium concentration  renal stones  in skin: - loss of collagen  thin, weakened integumentary tissues  purple striae; rupture of small vesels <ul><li>thin, atrophic skin is easily damaged, leading to skin breaks </li></ul><ul><li>and ulceration </li></ul><ul><li>Hyperpigmentation: due to very high levels of ACTH - manifestation in: </li></ul><ul><li>mucous membranes, hair, and skin </li></ul><ul><li>Hypertension: results from permissive effect of cortisol on the actions of </li></ul><ul><li>the catecholamines (KA)   vascular sensitivity to KA  </li></ul><ul><li> vasoconstriction  hypertension </li></ul>
  26. 28. <ul><li>Suppression of the immune system   susceptibility to infections </li></ul> alteration of mental status - from irritability and depression up to schizophrenia <ul><li>symptoms and signs of  adrenal androgen s level in women: </li></ul>-  hair growth (especially facial hair) - acne - oligoamenorrhea - changes of the vois <ul><li>hyperglycemia, glycosuria, hypokalemia, metabolic alkalosis </li></ul><ul><li>Excessive Secretion Of Thyreotrophin and Gonadotrophins is rare </li></ul>
  27. 30. Measurement of anterior pituitary hormones <ul><li>Measured in serum by immunoassay </li></ul><ul><li>Pulsatility of secretion of some of these hormones makes inappropriate to rely on single measurements for diagnostic purposes </li></ul><ul><li>Dynamic tests/ functional tests are important tools in ix. pituitary functions and other endocrine organs. </li></ul><ul><li>Basic principle of dynamic tests: </li></ul><ul><li>Hypofunction - stimulation tests </li></ul><ul><li>Hyperfunction-suppression tests </li></ul>
  28. 33. Treatment <ul><li>Hormone replacement therapy, including glucocorticoids, thyroid hormone, sex steroids, growth hormone and vasopressin, is usually free of complications. </li></ul><ul><li>Glucocorticoid replacement require careful dose adjustments during stressful events. </li></ul>
  29. 34. <ul><li>THANK YOU </li></ul><ul><li>QUESTION????? </li></ul>

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