_pituitary_gland_disorders for every one.ppt
- 1. Pituitary Gland Disorders DR JABBAR JASIM
- 2. Pituitary Gland. The pituitary is located at the base of the brain, in a small depression of the sphenoid bone (sella turcica). Purpose: control the activity of many other endocrine glands. ā Master glandā Has two lobes, the anterior & posterior lobes.
- 3. Anatomy Anterior lobe: glandular tissue, accounts for 75% of total weight. Hormones in this lobe are controlled by regulating hormones from the hypothalmus (stimulate or inhibit) Posterior: nerve tissue & contains axons that originate in the hypothalmus. Therefore this lobe does not produce hormones but stores those produced by the neurosecretory cells in the hypothalmus.
- 4. Histological finding is usually only performed as part of a therapeutic operation. Conventional histology identifies tumours as chromophobe (usually non-functioning), acidophil (typically prolactin- or growth hormone-secreting) or basophil (typically ACTH-secreting); immunohistochemistry may confirm their secretory capacity but is poorly predictive of growth potential of the tumor.
- 6. Anterior Pituitary Secretes: GH: stimulates growth of bone and muscle , promotes protein synthesis and fat metabolism. ACTH (Adrenocorticotropin ): stimulates adrenal gland cortex secretion of mineralcorticoids (aldosterone) & glucocorticoids (cortisol). TSH: stimulates thyroid to increase secretion of thyroxine, its control is from regulating hormones in the hypothalmus.
- 7. Anterior Pituitary Contād Prolactin: stimulates milk production from the breasts after childbirth to enable nursing. FSH: promotes sperm production in men and stimulates the ovaries to enable ovulation in women. LH and FSH work together to cause normal function of the ovaries and testes. LH: regulates testosterone in men and estrogen, progesterone in women.
- 8. Posterior Pituitary Antidiuretic hormone or ADH - also called vasopressin, vasoconstricts arterioles to increase arterial pressure; increases water reabsorption in distal tubules. Oxytocin: stimulates uterus to contract at childbirth; stimulates mammary ducts to contract (milk ejection in lactation).
- 9. Anterior Pituitary Disorders Hormone Increased level Decreased level GH Gigantism (child) Acromegaly (adult) Dwarfism (child) Lethargy, premature aging ACTH Cushingās Disease Addisonās Disease TSH Goiter, increased BMR, HR, BP Graves disease Decreased BMR, HR, CO, BP Cretinism (children) Prolactin amenorrhea Too little milk FSH Late puberty, infertility LH Menstrual cycle disturbance Amenorrhea, impotence
- 10. Posterior Pituitary Disorders Hormone Increased Decreased Oxytocin Precipitates childbirth, excess milk Prolonged childbirth, diminished milk ADH (vassopressin) Increased BP, decreased urinary output, edema. SIADH Diabetes insipidus, dilute urine & increased urine output
- 12. 20.57 Causes of anterior pituitary hormone deficiency Body_ID: B020057 Body_ID: None Structural ļ· Primary pituitary tumour o Adenoma* o Carcinoma (exceptionally rare) ļ· Craniopharyngioma* ļ· Meningioma* ļ· Secondary tumour (including leukaemia and lymphoma) ļ· Chordoma ļ· Germinoma (pinealoma) ļ· Arachnoid cyst ļ· Rathke's cleft cyst ļ· Langerhans cell histiocytosis ļ· Haemorrhage (apoplexy)
- 13. Inflammatory/infiltrative ļ· Sarcoidosis ļ· Lymphocytic hypophysitis ļ· Haemochromatosis ļ· Infections, e.g. pituitary abscess, TB, syphilis, encephalitis Congenital deficiencies ļ· GnRH (Kallmann's syndrome)*-gonadotrophin-releasing hormone ļ· GHRH*-growth hormone-releasing hormone ļ· TRH-thyrotrophin-releasing hormone ļ· CRH-corticotrophin-releasing hormone Functional* ļ· Chronic systemic illness ļ· Anorexia nervosa ļ· Excessive exercise
- 14. a striking degree of pallor is usually present, principally because of lack of stimulation of melanocytes by Ī²- lipotrophic hormone (Ī²-LPH, a fragment of the ACTH precursor peptide) in the skin. Finally, TSH secretion is lost with consequent secondary hypothyroidism. This contributes further to apathy and cold intolerance. In contrast to primary hypothyroidism, frank myxoedema is rare, presumably because the thyroid retains some autonomous function.
- 15. The onset of all of the above symptoms is notoriously insidious. However, patients sometimes present acutely unwell with glucocorticoid deficiency. This may be precipitated by a mild infection or injury, or may occur secondary to pituitary apoplexy
- 16. Managementof panhypopitiutarisim sodium depletion is not an important component to correct. Cortisol replacement Hydrocortisone should be given if there is ACTH deficiency. Mineralocorticoid replacement is not required. Thyroxine 100-150 Ī¼g once daily should be given. It is dangerous to give thyroid replacement to patients with adrenal insufficiency without first giving glucocorticoid therapy, since this may precipitate adrenal crisis.
- 17. Sex hormone replacement This is indicated if there is gonadotrophin deficiency in men of any age and in women under the age of 50 to restore normal sexual function and to prevent osteoporosis Growth hormone replacement daily subcutaneous self-injection, once the epiphyses had fused. GH replacement should be started at a low dose, with monitoring of the response by measurement of serum insulin-like growth factor-1 (IGF-1) levels.
- 18. All patients with biochemical evidence of pituitary hormone deficiency should have an MRI or CT scan to identify pituitary or hypothalamic tumours. If a tumour is not identified, then further investigations are indicated to exclude infectious or infiltrative causes
- 19. Anterior pituitary hyper function Results in excess production and secretion Results in excess production and secretion of one or more hormones such as GH, PRL, of one or more hormones such as GH, PRL, ACTH. ACTH. Most common cause is Most common cause is a benign adenoma. a benign adenoma.
- 21. Anterior pituitary adenoma, a benign tumor which is classified according to size, degree of invasiveness and the hormone secreted. Prolactin and GH are the hormones most commonly over-produced by adenomas. Pituitary Adenoma
- 22. Increased GH a statue of Robert Wadlow, the "Alton Giant," who measured 8 feet 11 inches at the time of his death.
- 23. Gigantism is the result of GH hypersecretion before the closure of the epiphyseal plates (childhood). ļ¬ Abnormally tall but body proportions are normal Acromegaly is over secretion of GH in adulthood ļ¬ Continued growth of boney, connective tissue leads to disproportionate enlargement of tissue..
- 24. Acromegaly Rare condition ā develops between ages 30-50 Symptoms: ā¢Coarsening of facial features ā¢Enlarged hands & feet ā¢Carpel trunnel syndrome ā¢Excessive sweating & oily skin ā¢Headaches ā¢Vision disturbance ā¢Sleep apnea ā¢General tiredness ā¢Oligomenorrhea or amenorrhea ā¢Impotence (adult males) ā¢Decreased libido
- 26. Diagnosis History & physical exam Investigation includes: ļ¬ GH analysis (glucose tolerance) GH analysis (glucose tolerance) Normally GH concentarion falls with oral glucose; in acromegaly it does not. ļ¬Prolactin levels as well as other pituitary function tests ļ¬MRI or CT & visual field tests to determine size and position of the adenoma. ļ¬Bone scan
- 28. Treatment Surgery (primary choice) Radiotherapy Drug treatment ā when surgery is not feasible Combinations of above
- 30. craniophyrngioma
- 31. Hypopituitarism- Anterior Pituitary Decreased GH in child: Dwarfism Condition of being undersized There are many forms of dwarfism Dwarfism related to pituitary gland is the result of insufficient GH Pituitary dwarfism is dwarfism is successfully treated by successfully treated by administering human administering human growth hormone growth hormone
- 32. Dwarfism, condition of being undersized, or less than 127 cm (50 in) in height. Some dwarfs have been less than 64 cm (24 in) tall when fully grown. Cretinism, a result of a disease of the thyroid gland, Achondroplasia, a disease characterized by short extremities resulting from absorption of cartilaginous tissue during the fetal stage;
- 33. Hyperprolactemia Hyperprolactemia Prolactin levels are normally high during pregnancy and lactation. Symptoms of hyperprolactemia include; ļ¬discharge from breasts (galactorrhoea) ļ¬oligomenorrhoea or amenorrhoea in women ļ¬reduced libido and potency in men ļ¬pressure effects (e.g. headache and visual disturbance) - more commonly in men
- 34. prolactin is not secreted in pulsatile fashion, although it rises with significant psychological stress. Assuming that the patient was not distressed by venepuncture, a random measurement of serum prolactin is sufficient to diagnose hyperprolactinaemia
- 36. level: >3000 mU/l (>150 mcg/l) is indicative of Microprolactinoma level: >6000 mU/l (>300 mcg/l) is indicative of Macroprolactinoma level <2000 mU/l with a pituitary macro lesion is indicative of ādisconnectionā hyperprolactinoma from a non-functioning pituitary macroadenoma
- 37. Medications causes hyperprolactinemai Medications causes hyperprolactinemai Dopamine receptor agonists (metoclopramide, domperidone), Neuroleptics (phenothiazines, risperidone, olanzapine), Antidepressants (tricyclic, MAO-inhibitors, SSRIs), Anti-hypertensives (verapamil, methyldopa, reserpine), Opiates & cocaine and Oestrogens.
- 39. Dopamine agonist
- 41. Increased ACTH:Cushingās Disease Cushing's is a disorder in which the adrenal glands are producing too much cortisol (hypercotisolism). If the source of the problem is the pituitary gland, then the correct name is Cushing's Disease whereas, if it originates anywhere else (adrenal tumors, long term steroid administration) then the correct name is Cushing's Syndrome. Cushingās Disease is caused by pituitary hypersecretion of ACTH.
- 43. Posterior Lobe Disorders SIADH & diabetes insipidus are major disorders of the posterior pituitaryā¦ā¦ however Even if posterior lobe becomes damaged, hormonal deficiencies usually do not develop becauseā¦ā¦??
- 44. SIADH Syndrome of Inappropriate Anti-Diuretic Hormone Too much ADH produced or secreted. SIADH commonly results from malignancies, CHF, & CVA - resulting in damage to the hypothalamus or pituitary which causes failure of the feedback loop that regulates ADH. Client retains water causing dilutional hyponaetremia & decreased osmolality.
- 45. Signs and Symptoms Lethargy & weakness Confusion or changes in neurological status Cerebral edema Muscle cramps Decreased urine output Weight gain without edema Hypertension
- 46. Assessment Serum sodium low Serum osmolality low Urine osmolality disproportionately elevated in relation to the serum osmolality Urine specific gravity elevated Plasma ADH elevated
- 47. Treatment of SIADH Treat underlying cause Hypertonic or isotonic IV solution Restrict fluid intake Medic Alert Lithium inhibits action of ADH to promote water excretion.
- 48. Diabetes Insipitus (DI) DI is usually insidious but can occur with damage to the hypothalamus or the pituitary. (neurogenic DI) May be a result of defect in renal tubules, do not respond to ADH (nephrogenic DI) Decreased production or release of ADH results in massive water loss Leads to hypovolemic & dehydration.
- 49. Clinical Manifestations Polyuria of more than 3 litres per 24 hours in adults (may be up to 20!) Urine specific gravity low Polydipsia (excessive drinking) Weight loss Dry skin & mucous membranes Possible hypovolemia, hypotension, electrolyte imbalance
- 50. Diagnostic Tests Serum sodium Urine specific gravity Serum osmolality Urine osmolality Serum ADH levels Vasopressin test and water deprivation test: increased hyperosmolality is diagnostic for DI.
- 52. Management Medical management includes Rehydration IV fluids (hypotonic) Symptom management ADH replacement (vasopressin) For nephrogenic DI: thiazide diuretics, mild salt depletion, prostaglandin inhibitors (i.e. ibuprophen)
Editor's Notes
- #3: Pituitary = hypophysis Anterior lobe called the adenohypophysis Posterior lobe called the neurohypophysis
- #6: GH: stimulates growth; promotes active transport of amino acids into cell & influences the rate at which CHO and fats are catabolized. Stimulates growth in childhood, is important for maintaining a healthy body composition and well-being in adults. In adults it is important for maintaining muscle mass as well as bone mass. It also plays a role in maintenance of constant blood sugar levels (through conversion of conversion of glycogen to glucose) ACTH (Adrenocorticotropin ): stimulates adrenal gland cortex secretion of mineralcorticoids (aldosterone) & glucocorticoids (cortisol). Cortisol, a so-called "stress hormone" is vital to survival. It helps maintain blood pressure and blood glucose levels. Aldosterone maintain electrolyte/water balance. TSH: stimulates thyroid to increase secretion of thyroxine, regulates the body's metabolism, energy, growth and development, and nervous system activity- vital to survival
- #7: Prolactin: stimulates milk production from the breasts after childbirth to enable nursing; controlled by regulating hormones from hypothalmus.can FSH: promotes sperm production in men and stimulates the ovaries to enable ovulation in women. LH and FSH work together to cause normal function of the ovaries and testes. LH: regulates testosterone in men and estrogen in women
- #8: ADH & oxytocin are called EFFECTOR hormones b/c they produce an effect when secreted. Whereas: Hypothalmic hormones stimulate the posterior pituitary to release TROPHIC (gland-stimulating) hormones.
- #9: Trophic hormones: stimulate another gland. i.e. ACTH, TSH, FSH, LH. Major causes of pituitary disease include tumors, pituitary infarction, genetic disorders and trauma. Pituitary tumors produce local (increased pressure in the cranium ā visual field abnormalities, headaches and somnolence) and systemic effects from over or under production of hormones.. Treatment involves removal of pituitary tumors.
- #22: GH is a hormone necessary for growth, regulates cell division, synthesis of protein. It exerts metabolic effects on organs, skin, muscle and connective tissue. GH is a peptide anterior pituitary hormone essential for growth. GH-releasing hormone stimulates release of GH. GH-inhibiting hormone suppresses the release of GH. The hypothalamus maintains homeostatic levels of GH. Cells under the action of GH increase in size (hypertrophy) and number (hyperplasia). GH also causes increase in bone length and thickness by deposition of cartilage at the ends of bones. During adolescence, sex hormones cause replacement of cartilage by bone, halting further bone growth even though GH is still present. Too little or two much GH can cause dwarfism or gigantism, respectively.
- #24: Acromegaly is a very rare condition and usually develops between the ages of 30 and 50. If the condition develops before a person has stopped growing (which usually occurs between the ages of 15 to 17 years of age), it causes gigantism because growth hormone promotes growth of bones in the body.
- #26: History: note change in hat, glove, shoe or ring size. Report fatigue and lethargy Backache & arthralgia Visual defects and headaches Laboratory Analysis In hyperpituitarism, usually only one hormone is produced in excess, most common being PRL, ACTH, GH Physical Exam Changes in facial features; in head, hand & foot size Arthritic type changes Vision changes from compression on optic nerves HTN Organomegaly (cardiac or hepatic) Deepened voice Dysphagia from enlarged toungue
- #28: Acromegaly may be treated by operating on the pituitary gland, by radiotherapy, by drug treatment, or a combination of these. The aim of all treatments is to reduce growth hormone levels to normal as this is associated with the disappearance of symptoms and improvement of your general wellbeing. Transphenoidal pituitary surgery and removal of adenoma. Surgery is the gold standard of treatment in clients who are acceptable surgical risks. Radiation is indicated in clients where surgery failed to bring GH down to normal levels or in poor surgical candidates. There is a higher risk of panhypopituitarism with this. However neurologic complications are possible such as visual loss, weakness and memory impairment.
- #33: Increased levels caused by: prolactin-secreting pituitary tumor A non-secreting tumor that prevents dopamine (PRIH) from reaching normal prolactin-producing cells.
- #41: Cushing's disease. This is a problem arising in the pituitary gland caused by a tumour which overproduces a hormone called ACTH. This in turn stimulates the adrenal glands to overproduce the steroid hormone cortisol. Cushing's syndrome can also be caused by a small growth in one, or both, of the adrenal glands. Cushing's is rare and is more often found in women than in men. It can affect all age groups, but the peak incidence is in middle age. Typical symptoms behaviourial changes, depression and mood swings, occasionally psychological problems can be severe face tends to be rounder (moon face) and redder weight gain around the trunk (central obesity) muscle wasting and proximal myopathy (patients have difficulty standing from a seated position without use of arms) tendency to bruise easily appearance of red 'stretch marks' on the abdomen, similar to those which occur during pregnancy irregular periods (oligomenorrhoea) or loss of normal menstrual function (amenorrhoea) - females impotence - males reduced fertility decrease in sex drive increase in hair growth on the face and body (hirsutism) increase in blood pressure development of mild diabetes mellitus Because Cushing's progresses slowly and gradually in most cases, it can go unrecognised for some time.
- #43: the hypothalmus continues to produce the ADH & oxytocin.
- #44: Excessive production of ADH secreted from posterior pituitary or an ectopic source. Often the result of a carcinoma (i.e. lung oat cell ca), also infections, trauma, drugs. Key features are water retention, hyponatremia and hypo-osmolality
- #45: Water intoxication
- #46: Serum sodium (hyponatremia) Serum osmolality (low) Urine specific gravity (increased)
- #47: Medications: diuretics
- #48: Diabetes Insipidus Diabetes insipidus (DI) literally means the passage of copious volumes of urine 'lacking taste', in contrast to the 'sweet tasting' urine typical of diabetes mellitus. DI is characterized by the production of large volumes of dilute urine (more than 3 litres per day) and constant thirst. It can have a number of causes but inadequate secretion of AVP (ADH), the pituitary hormone that controls kidney urine flow and concentration, is the most common. Water balance is normally achieved by three mechanisms: adequate vasopressin secretion thirst appreciation and drinking vasopressin-responsive kidneys The hypothalmus normally detects dehydration, sends a message to the pituitary, which in turn releases ADH, and sends it to the kidney. The kidney acts on the collecting and distal tubules to reabsorb to restore fluid balance. With excess fluid balance, the hypothalmus sends a message to the pituitary to inhibit secretion of ADH, promoting excretion of fluid. Trauma, infection or tumor growth in the region of the hypothalamus or pituitary may reduce the secretion of vasopressin. Pituitary surgery can result in transitory DI, but in some cases it may be permanent and may also be accompanied by the loss of other pituitary hormones. A deficiency of ADH results in inability to conserve water. Vasopression is given in acute phase.
- #50: Serum sodium (hypernatremia) Urine specific gravity (low) Serum osmolality (high) Urine osmolality (decreased) Serum ADH levels: decreased Vasopressin test and water deprivation test: increased hyperosmolality is diagnostic for DI. After administering vassopressin ā normally people will show a concentration of urine but not as pronounced as those with DI.