Assisting in Endocrinology

1. Assisting in Endocrinology Chapter 45

2. Learning Objectives Define, spell, and pronounce the terms listed in the vocabulary. Apply critical thinking skills in performing patient assessment and care. Summarize the anatomy of the endocrine system. Explain the mechanism of hormone action. Differentiate among common endocrine disorders. Describe the diagnostic criteria for diabetes mellitus.

3. Learning Objectives Outline the treatment plan and management of diabetes mellitus. Perform blood glucose screening with a glucometer. Identify the characteristics of hyperglycemia and hypoglycemia. Compare and contrast prediabetes, type 1, type 2, and gestational diabetes mellitus. Categorize the complications associated with diabetes mellitus. Summarize patient education approaches to diabetes.

4. Endocrine System The endocrine system consists of glands located throughout the body that produce and secrete hormonesthat are excreted directly into the bloodstream where they can be carried to target tissue. Hormones are the body’s chemical messengers, transferring information from one group of cells to another. Hormones control growth, mood, system functions, metabolism, sexual maturity, and reproduction. Hormone levels vary and can be affected by outside factors such as illness and stress.

5. Location of the Endocrine Glands From Gould B: Pathophysiology for the health professions, ed 3, St Louis, 2006, Saunders.

6. Hypothalamus and Pituitary The hypothalamus is an area of the brain that contains the pituitary gland, which produces the "controlling" hormones. These hormones regulate body processes such as metabolism and control the release of hormones from glands such as the thyroid, the adrenals, and the gonads (testes or ovaries). Pituitary gland Anterior—regulates thyroid, adrenals, gonads by producing GH, TSH, ACTH, prolactin, FSH, LH Posterior—oxytocin and ADH

7. Pituitary Hormones From Thibodeau GA, Patton KT: The human body in health and disease, ed 4, St Louis, 2005, Mosby.

8. Endocrine Glands Pineal gland—melatonin helps regulate waking and sleeping patterns Thyroid—thyroid hormones regulate metabolism Parathyroid—controls level of calcium in blood Thymus—stimulates production of T cells Adrenals—cortex produces corticosteroids and medulla produces adrenaline Gonads—testes produce testosterone and ovaries produce eggs Pancreas—insulin and glucagon to regulate blood glucose

9. Mechanisms of Hormone Action The endocrine system is a network of ductless glands and other structures that secrete hormones directly into the bloodstream. Hormones are chemical transmitters produced by glands and transported to target tissue or organs by the bloodstream. Disorders of the endocrine system are caused by either hypersecretion or hyposecretion of hormones. Treatment is designed to control hypersecretion or replace hormones that are not at therapeutic levels.

10. Posterior Pituitary Disorders Diabetes insipidus—usually caused by tumor ADH or vasopressin not produced or released in sufficient amounts Without ADH, fluid not reabsorbed in the renal tubules Signs and symptoms—polyuria, polydipsia, nocturia, decreased specific gravity Can cause fatal dehydration Treatment: synthetic vasopressin (desmopressin) nasal spray

11. Anterior Pituitary Disorders Panhypopituitarism—deficiency in all hormones produced by the anterior pituitary GH abnormalities Hyposecretion Hypopituitary dwarfism Hypersecretion Gigantism—prepuberty; caused by tumor Acromegaly—adults; causes excessive growth of the bones of the face and extremities, CHF, DM, and other health problems

12. Thyroid Gland Although the thyroid gland releases the hormones that govern growth and metabolism, the brain (the pituitary and the hypothalamus) manages the release and the balance of the amount of hormones circulated. When stimulated by TSH from the anterior pituitary, the thyroid gland produces the thyroid hormones triiodothyronine (T3) and thyroxine (T4), which control the body’s metabolic rate and are important factors in bone growth and nervous system development in children.

13. Hypothyroidism Hypothyroidism is a decreased activity of the thyroid gland, which may affect all body functions. The rate of metabolism slows, causing mental and physical sluggishness. The most severe form of hypothyroidism is myxedema, which is a medical emergency.

14. Hyperthyroidism Hyperthyroidism or thyrotoxicosis results from excess quantities of thyroid hormone in the body. Excess may be caused by tumors of the thyroid or inflammation of the thyroid. Increased thyroid hormone levels cause heat intolerance, increased energy, difficulty sleeping, diarrhea, and anxiety.

15. Thyroid Disorders Hypothyroidism Simple goiter—endemic iodine deficiency; thyroid enlarges to try to produce enough hormones Cretinism—congenital lack of thyroid hormones Myxedema—chronic hypothyroidism in older child or adult; fatigue, weight gain, hair loss, bradycardia, and so on; treatment is Synthroid or Levothroid daily for rest of life Hyperthyroidism (thyrotoxicosis) Signs and symptoms—weight loss, tachycardia, nervousness, exophthalmos, tremor, goiter, palpitations Graves’ disease most common type—autoimmune Treatment: drugs, radiation, surgery

16. Adrenal Gland Disorders Addison’s disease—hyposecretion; autoimmune disease of adrenal cortex; rare Treatment: daily corticosteroids Cushing’s syndrome—hypersecretion of adrenal cortex Pituitary or adrenal tumor Excessive levels of cortisol Increased adipose tissue, moon face, cervical spine fat pads, glucose intolerance, muscle wasting, problems with healing, mental disorders Treatment: medication, radiation, surgery

17. Pancreas The pancreas contains islets of Langerhans, which produce and secrete the hormones insulin and glucagon. When the blood glucose level is too high, beta islet cells secrete insulin, which is sent through the bloodstream to the target tissue site to conduct glucose into the cell. Glucagon is secreted by the alpha islet cells when blood glucose levels are low to stimulate the liver to convert glycogen into circulating glucose.

18. Diabetes Mellitus If there is resistance to insulin at the target cell membrane or there is not enough insulin to help transport glucose from the blood into the cells, an individual experiences a variety of symptoms. Signs and symptoms—glycosuria, polyuria, polydipsia, polyphagia, rapid weight loss, drowsiness, visual disturbances, skin itchiness, and infections.

19. Prediabetes Diagnosis – FBS between 100 and 125mg/dl; 2-hour OGTT of 140 to 199 mg/dl Long-term damage to vascular and cardiac systems may be occurring during prediabetes Majority of individuals with prediabetes develop type 2 diabetes within 10 years

20. Diagnostic Criteria for Diabetes Mellitus NFBS equal or above 200 mg/dl (norm 80 to 120) with symptoms FBS equal or above 126 mg/dl (norm 70 to 110) more than once OGTT—2-hour glucose equal or above 200 mg/dl Urinalysis + glucose and/or ketones Glycosylated hemoglobin >7% (norm 4% to 6%)

21. Glucose Tests Fasting blood sugar (FBS or FPG)—taken after patient has been without food or drink for 12 hours; more accurately assesses blood glucose level than random level. Glucose tolerance test (GTT or OGTT) measures body’s ability to metabolize concentrated oral glucose load; first draw an FBS, then measure glucose levels from 1 to 5 hours. Glycosylated hemoglobin level (HbA1c)—accurate measure of glucose control for preceding 3 months; measures glucose levels that are chemically bound to hemoglobin molecule on the RBC; may be performed without fasting; the higher the result, the greater the risk for complications. Should be <6.5% – A1c of 7% = FBS of 70 to 110.

22. Correlation between A1c Levels and FPG Levels A1c (%) Plasma Glucose (mgdl) 6 135 7 170 8 205 9 240 10 275

23. Type 1 Diabetes Mellitus In response to high levels of glucose in the blood, the beta islet cells in the pancreas secrete the hormone insulin. Type 1 diabetes occurs when the beta islet cells are destroyed by autoimmune, genetic, or environmental factors.

24. Type 1 Diabetes Mellitus Type 1 or immune-mediated diabetes usually develops before age 30 years; previously called juvenile or insulin-dependent diabetes (IDDM). Insulin is no longer being produced, so insulin administration is required. Treatment goal: maintain blood glucose levels as close to normal as possible. Insulin administered via SQ injections, pump, or injector pen; inhaler, patch, and tablet being researched.

25. Insulin Types Patients must receive a combination of insulin types throughout the day; typically combination of fast-acting and intermediate insulin before each meal and long-acting at bedtime. Fast acting—Lispro and Regular Intermediate—NPH and Lente Long-acting—Ultralente Combinations of NPH and Regular can be ordered Refer to Table 45-1

26. Treatment Complicated combination of insulin therapy, glucometer screening, diet, and exercise. Glucometer screening on a regular basis (several times a day) will help track therapeutic success and possibly indicate the need for additional insulin. MA should be prepared to instruct the patient on how to perform and record accurate glucometer screenings. Patient should work with dietician to manage appropriate diet based on glycemic index of foods. Patient should be closely monitored if ill, because insulin changes may be required.

27. Glucometers A person with diabetes constantly manages his or her blood glucose levels. After a blood sample is taken and tested, it is determined whether the glucose levels are low or high. If glucose levels are too low, carbohydrates are ingested. If glucose in the blood is too high, the appropriate amount of insulin is administered into the body. Refer to Procedure 45-1.

28. Blood Glucose Monitoring Device Courtesy Home Diagnostics, Fort Lauderdale, Florida.

29. Glucometer Quality Control Some examples of quality control methods include: Correctly follow manufacturer’s instructions. Perform instrument maintenance specified by the manufacturer, including correct cleaning and storage of the instrument. Check expiration dates on test strips and solutions and store these products correctly. Match and correctly enter the test strip code into the instrument before use. Contact the physician if test results do not match patient symptoms.

30. Alternative Insulin Administration Methods Insulin pump – computerized device that administers a constant dose of insulin using a small portable pump; programmed to deliver a measured dose of insulin by continuous subcutaneous infusion through a catheter that is placed in the abdomen or buttocks areas; more closely resembles the body’s normal surge of insulin and is designed to maintain blood glucose levels consistently within normal limits. Insulin can be administered through an injector pen that comes in preloaded cartridges for easy use. Insulin pens are disposable or refillable and easily portable.

31. Type 2 Diabetes Mellitus: Signs and Symptoms Increased hunger Polydipsia Polyuria Blurred vision Fatigue Numbness or tingling in hands and feet Slow healing Frequent infections Impotence

32. Type 2 Diabetes Mellitus Once called adult-onset diabetes or NIDDM; 90% to 95% of all people with diabetes Risk factors: family history, history of gestational diabetes, sedentary lifestyle, obesity Caused by decreased insulin production and/or decreased target cell sensitivity to insulin Treatment: weight loss, exercise, diet, oral hypoglycemics (refer to Table 45-2); medications stimulate pancreas to produce more insulin and decrease cellular insulin resistance; over time may require insulin injections

33. Injectable Drugs for Management of Type 1 and Type 2 Diabetes Pramlintide (Symlin) – synthetic form of the hormone amylin that works with insulin and glucagon to maintain normal blood glucose levels; injections taken before meals help improve A1c levels by decreasing the rate of movement of food through the stomach thereby preventing a sharp increase in blood plasma levels after meals. Exenatide (Byetta) lowers blood glucose levels by increasing insulin secretion; injected 60 minutes before breakfast and dinner; helps patients achieve modest weight loss and improved glycemic control. Not for use in patients with Type 1 diabetes.

34. Hypoglycemia Low blood glucose (<70 mg/dl), sudden onset of symptoms Poor coordination Angry, moody Pale skin Confusion and disorientation Sudden hunger Diaphoresis Tremor May result in insulin shock Elevated insulin levels

35. Hyperglycemia High blood glucose (>126 mg/dl) Gradual onset of symptoms Sleepiness Excessive thirst Polyuria Flushed skin color Nausea and vomiting Acetone breath (fruity smelling) Heavy breathing May result in diabetic coma Low insulin levels

36. Treating Hypoglycemia: Rule of 15 15 g of CHO every 15 minutes until blood glucose level is above 80 mg/dl Treat if blood glucose level is below 70 15 g of CHO = 4–5 lifesavers 4 oz orange juice 8 oz skim milk

37. Hyperglycemia and Hypoglycemia Hyperglycemia—rapid onset; causes “fruity” breath; can cause ketoacidosis (diabetic coma) Too little insulin Too many calories Decreased exercise Illness Stress Treatment Exercise if possible Decrease caloric intake Increase insulin dose or time doses differently Hypoglycemia—slow onset; may cause insulin shock Too much insulin Not enough calories Overexercise Treatment Ingest glucose tablets Glucometer check in 15 to 20 minutes If still low, another glucose tablet

38. Gestational Diabetes Diagnosed in pregnant woman if she has either: FBS >105 mg/dl OGTT abnormality Risk factors—older age, obesity, history of large infants, family history, previous birth complications (fetal death, anomalies), smokers, certain ethnic groups May be asymptomatic; all women screened between twenty-fourth and twenty-eighth weeks of pregnancy Treatment: exercise, calorie reduction, insulin; most return to normal postpartum; are at increased risk for developing type 2 diabetes later in life

39. Complications of Diabetes Acute—hypoglycemia resulting in insulin shock or hyperglycemia causing ketoacidosis (diabetic coma) Chronic—can appear many years after diagnosis Microvascular—retinopathy, nephropathy Macrovascular—atherosclerosis, CAD, hypertension, CVA, PVD Diabetic neuropathy Infection—combination of increased risk of injury, decreased blood supply resulting from atherosclerosis, decreased phagocytosis. Prevention of skin trauma important.

40. Questions to Ask When Screening for Diabetic Neuropathy Can you feel your feet when walking? Have you noticed weakness in the muscles of your feet and legs? Do you have problems with balance when standing or walking? Do you have trouble feeling heat or cold in your feet or hands? Do you have open sores on your feet and legs that heal slowly? Have you noticed that your feet have changed shape? Do your feet tingle or feel like “pins and needles,” or do you have burning or shooting pains in your feet? Do they hurt at night? Are they numb? Are your feet very sensitive to touch? Do your feet and hands get very cold or very hot?

41. Diabetic Foot Problems People with diabetes are at risk for blood vessel injury, which may be severe enough to cause tissue damage in the legs and feet. Basic foot care is important for diabetic patients because of potential problems with their circulation.

42. Diabetic Foot Problems From Levin ME: Pathogenesis and general management of foot lesions in the diabetic patient. In Bowker JH, Pfeifer MA, editors: Levin and O’Neal’s the diabetic foot, ed 6, St Louis, 2001, Mosby.

43. Foot Care Basic foot care is important for diabetic patients because of potential problems with their circulation. Even a minor undetected injury can lead to serious problems. Feet should be inspected at each visit. Education guidelines—wash every day with warm water, cut nails straight across, apply lotion to prevent cracking, check feet every day, call physician at first signs of redness, do not go barefoot, check shoes for rough areas, wear well-fitting shoes, stop smoking (causes vasoconstriction).

44. Developing Diabetic Patient Education Many factors affect glucose levels—activity, stress, illness, medications, diet. Diet plan—maintain desirable body weight, help maintain homeostatic blood glucose level. Medication management with insulin or oral hypoglycemics must be strictly followed. Patient must understand how to perform glucometer readings and administer insulin. Involve family members to achieve success with diet, weight control, exercise, foot screening, medication administration, and prevention of complications.

45. Legal and Ethical Issues Document all patient teaching Advise patients to wear medic alert bracelet Patients must take medications as prescribed Newly diagnosed diabetic persons should avoid driving until glycemic control is stabilized and should be warned about possible visual impairment from the disease Remember that you are always representing your profession and employer, and respond to each situation accordingly Ask for assistance or further information if you feel unprepared to perform a procedure or to give accurate information