Endocrine System

1. Endocrine System I’m hot, I’m cold, I’m fast, I’m slow. EMT-Paramedic Program

2. The System Itself • The other regulating system of the body • Closely linked to nervous system • Uses glands and tissues • Via hormones, the system regulates: • growth • the use of foods for energy • pH of body fluids • fluid balance • reproduction • provides resistance to stress

4. Chemical messengers to either: Body organs Tissues Or Both Binding depends on: Quantity Quality of receptor sites They may be divided into three groups: Amines Tyrosine, epi, norepi Proteins amino acids; insulin, GH, calcitonin, ADH, oxytocin Steroids cholesterol; cortisol, aldosterone, estrogen, progesterone, and testosterone Hormones

5. Hormone Secretion • Negative feedback mechanism • Endocrine glands respond to blood level changes or other hormones present • Secretion of hormone until stimulus is negated or changed

6. Exocrine Glands – Ducted Gland • Release chemicals nearby tissues through a duct • Salivary glands

7. Endocrine Glands – Ductless Glands • Release chemicals directly into blood

8. Gland Effects • Exocrine glands – tend to be localized • Endocrine glands – tend to be widespread

9. Pituitary “Master Gland” • Posterior holds hypothalamus hormones ADH and oxytocin • Anterior produces GH, TSH, ACTH, prolactin, FSH, LH

10. Specific Hormones • ADH • maintains BP by reabsorption of water by kidney tubules and vasoconstriction • Oxytocin • stimulates contraction of uterus and release of milk

11. Specific Hormones Thyroid Stimulating Hormone Growth Hormone Anterior Pituitary Adrenocorticotropic Hormone

12. Anterior Pituitary • These hormones primarily regulate other endocrine glands; rarely a factor in endocrine emergencies. • TSH – (Thyroid-stimulating hormone) - stimulates thyroid to release hormones, = increased metabolic rate. (Critical for survival). • GH – (Growth hormone) - adults; decrease glucose use, increase consumption of fats for energy

13. Anterior Pituitary • ACTH – (Adrenocorticotropic hormone) - stimulates growth of the adrenal cortex & release of corticosteroids • FSH – (Follicle stimulating hormone) - ovarian release • LH – (Luteinzing hormone) - ovarian release • Estrogen and progesterone

14. Thyroid Gland • Produces: • T4 - Thyroxine • T3 – Triiodothyronine • Contain Iodine • Regulate energy production & growth • Calcitonin – • Regulates calcium • Maintains strong bones… • Also feeds back through pituitary

15. Parathyroid Glands • “Pair-a-thyroids?”  • Produces parathyroid hormone • Also involved in calcium & blood phosphate levels

16. Disorders Associated with Thyroid Gland • Issues directly associated with gland • Tumor • Pituitary malfunction indirectly affecting • Hypothyroidism (Myxedema) • Hyperthyroidism (Grave’s Disease) • Thyrotoxicosis • Thyrotoxic Crisis (Thyroid Storm)

17. Hypothyroidism • Inadequate levels of thyroid hormones • Most common cause for primary hypothyroidism is chronic lymphocytic thyroiditis (Hashimoto’s); more common in women. Can also be caused by iodine deficiency, surgery. Usually have a small goiter.

18. Hypothyroidism (Myxedema) • Sx: decreased metabolic rate, facial bloat, weakness, cold intolerance, lethargy, altered mental status, slowed speech, oily skin and hair, hair loss, weight gain. • Levothyroxine is drug of choice. • Patients may be difficult to wean from a ventilator after anesthesia.

19. Myxedema Coma • Trauma, emergency surgery, severe infection may be poorly tolerated and lead to myxedema coma. • Rare disorder, characterized by hypo-ventilation, hypotension, hypothermia, hyponatremia, hypoglycemia.

20. Hyperthyroidism • A toxic condition characterized by tachycardia, nervous symptoms, increased metabolism secondary to hyperactivity of the thyroid.

21. Hyperthyroidism (Thyrotoxicosis) • Excessive circulating thyroid hormone. • Graves disease; Most common cause (95%) • Familial, 6X more common in females and relatively often in elders. Best clinical marker; ophthalmopathy.

22. Hyperthyroidism (Thyrotoxicosis) • Sx: nervousness, diarrhea, insomnia, fatigue, dyspnea, A-fib w/o cardiac hx., tachycardia, HTN, heat intolerance, weight loss, exophthalmos, hair loss, palpitations, amenorrhea, edema of hands and face. • Elders; wasting with none of classic S/S, serious cardiac symptoms. • Younger adults; nervous system symptoms

23. Hyperthyroidism (Thyrotoxicosis) • Tx: Propranolol decreases many sx rapidly. • Diltiazem (calcium channel antagonist) if propranolol is contraindicated. • Iodide is effective for thyroid storm or prep. for thyroid surgery - short term tx.

24. Disorders of the Thyroid Gland • Thyroid Storm • Severe Tachycardia, Dysrhythmias • Heart Failure • Shock • Hyperthermia • Restlessness, Agitation & Paranoia • Abdominal pain • Delirium, Coma • What else does this look like? • What could help you distinguish? • Danger in becoming a cynic?

25. Adrenal Glands Each adrenal has: • Medulla • -Epinephrine • -Norepinephrine • Cortex • -Aldosterone • -Cortisol

26. Adrenal cortex • Secretes 3 classes of hormones - all steroid hormones • Glucocorticoids (95%) (Cortisol) • Release = increased glucose blood levels and other functions i.e., Anti-inflammatory and immune suppression - released in response to stress, trauma, serious infection. • Mineralocorticoids • Play an important role in regulating concentration of potassium and sodium • Androgenic hormones • Cause masculinization

27. Trouble Associated with Adrenal Gland Cushing’s Syndrome • ACTH Levels too high • Enlarges adrenal gland • May be associated with pituitary tumor

28. Addison’s Disease Deficiency of cortisol & aldosterone Slow, gradual onset Progressive Fluid volume deficit Hyperpigmentation (bronze) Anorexia Hypotension Disorders Associated with Adrenal Glands

29. Adrenal Gland Disorders Addisonian Crisis • Acute episode preceded by: • Physical or emotional stress • Surgery • Alcohol intoxication • Trauma • Infection • Hypoglycemia • Adrenal cortex cannot comply with body’s increased demand

30. Gonads • Endocrine glands associated with reproduction • Ovaries produce eggs - controlled by FSH & LH from anterior pituitary, also manufactures estrogen and progesterone - several functions; sexual development, preparation of uterus for implantation • Testes - produce sperm, manufacture testosterone - promote male growth and masculinization. Controlled by anterior pituitary hormones FSH and LH.

31. Ovaries Secrete • Estrogen • Progesterone progesterone

32. Testes Secrete • Testosterone • Inhibin

33. Pancreas • U R&L Q • Islets of Langerhans • Produce Glucagon & Insulin

34. Pancreatic Hormones • Glucagon – Alpha Cells • stimulates liver to change glycogen to glucose • raises blood glucose levels • Insulin – Beta Cells • lowers blood glucose levels by increasing transport of glucose into the cells

35. Glucose/Dextrose (D-glucose) • An intermediate in metabolism of carbohydrates • The most important carbohydrate, and is formed during digestion; absorbed from intestines into blood of portal vein; in passage through liver, is converted into glycogen

36. Glucose • May be: • Used immediately • Stored in muscles • Stored in fat • Brain cannot store it’s food • Requires continuous circulating volume • Reason neuro s/s develop quickly

37. Disorders Associated with Pancreatic Dysfunction Diabetes Mellitus • Hyperglycemia • Hypoglycemia • DKA • HHNK

38. Diabetes Mellitus • 16 million in U.S. & rising • 3 diagnostic types: • IDDM Type I • NIDDM Type II • Other (Secondary) DM

39. Diabetes Mellitus • IDDM type 1 • Most commonly occurs in children and young adults • Genetic predisposition; Immune mediated destruction of insulin-producing cells

40. Diabetes Mellitus • NIDDM type II • Usually occurs after age 30. • A strong genetic predisposition is evident but pathogenesis is different. • Most individuals obese • Resistance to insulin action is present. • Exogenous insulin not required.

42. Promotion of Hyperglycemia • Increased dietary intake (esp. carbohydrates) • Limitation of physical activity • Reduction of hypoglycemic therapy • Limitation of endogenous insulin production • Pancreatic diseases • Drug treatment • Electrolyte disorders

43. Diabetes Mellitus • Other (secondary) DM • Associates hyperglycemia to another cause including: • Pancreatic disease/Pancreatectomy • Drugs or chemical agents • Others too • Gestational diabetes • Develops during pregnancy and resolves with birth but increased risk of DM later.

44. Development of Insulin Resistance • Infection • Inflammation • Myocardial ischemia or infarction • Trauma • Surgery • Emotional stress • Pregnancy • Drug treatment

45. S/S of Hyperglycemia/Insulin Insufficiency or Resistance • Polyuria • Polydipsia • Nocturia • Weight Loss • Fatigue • Blurred vision

46. Control • Oral • Transplant • Islet cells • Pancreas

47. Oral Hypoglycemic Drugs Metformin 500-1000 mg PO tid Avandia 4 mg PO qd

48. Insulin

49. Diabetic Ketoacidosis • A result of severe insulin insufficiency and an excess of glucagon. Type I • Common causes: • Interruption of insulin therapy • Stress, infection • Non-compliance frequently a factor • Onset slow, from 12-24 hours.

50. Diabetic Ketoacidosis • Transition from glucose to lipid metabolism • Forms ketones & increase to toxic levels (diuresed) • Metabolic Acidosis • Symptoms • Causes severe osmotic diuresis and severe dehydration • Tx: Requires close monitoring • Draw red-top • Give IV fluids (Typically 3-5 L Low) • Consider thiamine • All vitamins & Electrolytes grossly deranged