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10 Major Diseases Learning Objectives After studying this chapter in the text, the student should be able to: 10.1 List the risk factors for cardiovascular diseases. 10.2 Summarize the risks and signs of metabolic syndrome. 10.3 Explain the impact and treatment of diabetes. 10.4 Discuss the risk factors and management of hypertension. 10.5 Specify the effects and management of blood cholesterol levels. 10.6 Outline the patterns and consequences of cardiovascular diseases. 10.7 Identify the risk factors and common causes of strokes. 10.8 Review the causes, risk factors, and types of cancer. 10.9 Describe common agents of infection and their effects on human health. Chapter Summary This chapter provides information about risk factors, preventive measure, silent dangers, and medical advances that can keep you healthy now and for years to come. Lecture Outline I. Your Cardiometabolic Health A. Introduction 1. “Cardio” refers to the heart and blood vessels of the cardiovascular system. 2. “Metabolic” refers to the biochemical processes involved in the body’s functioning. Chapter 10 – Major Diseases 3. Cardiovascular diseases account for one of every three deaths, including an increasing number among younger adults ages 35 to 54. B. Cardiometabolic Risk Factors 1. Specific risk factors determine your Cardiometabolic health. 2. Risk Factors You Can Control a. Overweight/Obesity i. Excess weight, an increasingly common and dangerous cardiometabolic risk factor in both men and women, undermines good health. b. Body Fat i. Apple-shaped people who carry most of their excess weight around their waists are at greater risk of cardiometabolic conditions than are pear-shaped individuals who carry most of their excess weight below their waist. ii. Fat, regardless of where it is stored, boosts the likelihood of heart attack or stroke. c. Waist Circumference i. A waist measurement of more than 40 inches in men and more than 35 inches in women indicates increased health risks. d. Physical Inactivity i. The risk for Cardiometabolic conditions is higher for people who are inactive than for those who engage in regular physical activity. e. Tobacco Use i. Smoking may be the single most significant risk factor for cardiometabolic conditions. f. High Blood Glucose i. “Insulin-resistant” cells no longer respond well to insulin, and so glucose, unable to enter the cells, builds up in the bloodstream. (a) Healthy blood glucose – under 100 (b) Prediabetes – 100 to 125 (c) Diabetes – more than 125 g. High Blood Pressure (Hypertension) i. Systolic – blood pressure when the heart contracts. ii. Diastolic – blood pressure when the heart is at rest. iii. A blood pressure reading consists of the systolic measurement “over” the diastolic measurement. iv. The higher the blood pressure reading the higher the risk of stroke. h. Lipoprotein Levels i. Cholesterol is a fatty substance found in certain foods and also manufactured by the body. ii. Lipoproteins are compounds in the blood that are made up of proteins and fat. Chapter 10 – Major Diseases iii. HDL – high-density lipoproteins are the “good guys.” iv. LDL – low-density lipoproteins are the “bad guys.” v. Triglycerides are fats that flow through the blood after meals and have been linked to increased risk of coronary artery disease, especially in women. 3. Risk Factors You Can’t Control a. Family History i. Certain cardiometabolic risk factors can be passed down from generation to generation. b. Race and Ethnicity i. Risk factors are at higher rates among ethnic minority populations. c. Age i. Risk factors increase as people get older, especially past the age of 45. d. Height i. Tall men are less likely to develop heart failure than shorter ones. However, it is not clear whether the extra inches protect the heart or whether shorter men differ in other ways. II. Metabolic Syndrome A. Overview 1. Once called Syndrome X or insulin-resistant syndrome. 2. Is not a disease but a cluster of disorders of the body’s metabolism— including high blood pressure, high insulin levels, abdominal obesity, and abnormal cholesterol levels—that make a person more likely to develop diabetes, heart disease, or stoke. B. Who Is at Risk? 1. This dangerous syndrome affects one in four Americans, especially Hispanic men and women, and may begin early in life. C. What Are the Signs? 1. Three or more of the following characteristics indicate metabolic syndrome: a. A larger-than-normal waist measurement b. A higher-than-normal triglyceride level c. A lower-than-normal high density lipoprotein level d. A higher-than-normal blood pressure e. A higher-than-normal fasting blood sugar 2. People with three factors of metabolic syndrome are nearly twice as likely to have a heart attack or stroke and more than three times more likely to develop heart disease than those with none. Chapter 10 – Major Diseases 3. College-age men and women who maintain their weight as they get older are much less likely to develop metabolic syndrome. III. Diabetes A. Overview 1. Glucose is the primary form of sugar that body cells use for energy. 2. When a person without diabetes eats a meal, the level of glucose in the blood rises, triggering the production and release of insulin by special cell clusters in the pancreas. 3. In those who have diabetes, however, insulin secretion is either nonexistent or deficient. 4. The levels of glucose in the blood rise higher and unused glucose passes through the kidneys, which are unable to process it. 5. Deprived of the fuel it needs, the body begins to break down stored fat as a source of energy bringing an upheaval in the body’s chemical balance that can cause many problems and even eventual death. B. Insulin Resistance 1. A condition in which the body produces insulin but does not use it properly. 2. Excess weight and lack of physical activity, along with genetic factors, contribute to insulin resistance. C. Prediabetes 1. Sometimes called impaired fasting glucose or impaired glucose tolerance. 2. A condition in which blood glucose levels are higher than normal but not high enough for a diagnosis of diabetes. D. Diabetes Mellitus 1. When the pancreas either stops producing insulin or does not produce sufficient insulin to meet the body’s needs, almost every body system can be damaged. 2. Diabetes mellitus, the seventh leading cause of death in the United States, shortens life expectancy by an average of eight years. E. D. Types of Diabetes 1. Diabetes includes several conditions in which the body has difficulty controlling levels of glucose in the bloodstream. a. Type 1 Diabetes i. In this form of diabetes, the body’s immune system attacks the insulin-producing beta cells in the pancreas and destroys them. Chapter 10 – Major Diseases b. Type 2 Diabetes i. In type 2, either the pancreas does not make enough insulin (insufficient insulin) or the body is unable to use insulin correctly (insulin resistance). c. Gestational Diabetes i. Women who get diabetes while pregnant are more likely to have a family history of diabetes and to develop diabetes later in life. 2. Although type 1 and type 2 diabetes have different causes, two factors are important in both: an inherited predisposition to the disease and something in the environment that triggers diabetes. a. a. In most cases of type 1 diabetes, people need to inherit risk factors from both parents and to experience some environmental trigger, which might involve prenatal nutrition, a virus, or an unknown agent. b. b. In type 2 diabetes, family history is one of the strongest risk factors for getting the disease, but only in Westernized countries. i. Excess weight, especially around the waistline, is the major and most controllable risk factor for type 2 diabetes. F. Diabetes Signs and Symptoms 1. Increased thirst and frequent urination 2. Flulike symptoms 3. Weight loss or gain 4. Blurred vision 5. Slow-healing sores or frequent infections 6. Nerve damage 7. Red, swollen, tender gums G. Diabetes Management 1. Before the development of insulin injections, diabetes was a fatal illness. Today diabetics can have normal lifespans. 2. Diabetes educators teach patients a new set of ABCs: a. A is for the A1c test. This test measures the amount of glucose attached to hemoglobin molecules, the iron-rich molecules in red blood cells that deliver oxygen to the body. b. B is for blood pressure. c. C is for cholesterol. H. Treatment 1. The goal for diabetics is to keep blood sugar levels as stable as possible to prevent complications, such as kidney damage. 2. Home glucose monitoring, allows diabetics to check their blood sugar levels as many times a day as necessary and to adjust their diet or insulin doses as appropriate. Chapter 10 – Major Diseases 3. Those with type 1 diabetes require daily doses of insulin via injections, an insulin infusion pump, or oral medication. 4. Those with type 2 diabetes often can control their disease through a wellbalanced diet, exercise, and weight management. However, insulin therapy may be needed to keep blood glucose levels normal or near normal. IV. Hypertension A. Introduction 1. Blood pressure refers to the force of blood against the walls of arteries. 2. Hypertension is a condition when blood pressure remains elevated over time and the heart pumps harder than is healthy. 3. This can lead to organs such as the heart, brain, and kidneys to start to deteriorate. 4. Especially when combined with obesity, smoking, high cholesterol levels, or diabetes, hypertension greatly increases the risks of cardiovascular problems. B. Who Is At Risk? 1. About 3 in 10 adults age 18 and older in the U.S.—some 65 million men and women—have high blood pressure. 2. Blood pressure has increased among children and adolescents as well as adults. 3. Different races suffer different consequences of high blood pressure. 4. Family history increases the risk. 5. Men and women are equally likely to develop hypertension, but in women, blood pressure tends to rise around the time of menopause. C. What Is a Healthy Blood Pressure? 1. Current guidelines categorize a reading of 120–139/80–89 as prehypertension, a condition that is likely to worsen in time. 2. A healthy reading is 115/75. 3. Once blood pressure rises above this threshold, the risk of cardiovascular disease may increase. 4. The current guidelines classify hypertension into two categories: a. Stage 1: This consists of a systolic pressure ranging from 140 to 159 or a diastolic pressure ranging from 90 to 99. b. Stage 2: The most severe form of hypertension occurs with a systolic pressure of 160 or higher, or a diastolic reading of 100 or higher. D. Lowering High Blood Pressure 1. Lifestyle changes are the first line weapon in the fight against high blood pressure. Chapter 10 – Major Diseases 2. A low-carbohydrate diet may be the most effective for lowering blood pressure. 3. Medications - drugs for lowering blood pressure come in a range of regiments with a range of effects on other conditions, interactions with other drugs, and potential side effects. V. Your Lipoprotein Profile A. Overview 1. This blood test, which should be performed after a 9- to 12-hour fast and repeated at least once every five years, provides readings of: a. Total cholesterol. b. LDL (bad) cholesterol, the main culprit in the buildup of plaque within the arteries. c. HDL (good or healthy) cholesterol, which helps prevent cholesterol buildup. d. Triglycerides, the blood fats released into the bloodstream after a meal. B. What Is a Healthy Cholesterol Reading? 1. Less than 200 mg/dL is the ideal level that puts you at lower risk for heart disease 2. 200 to 239 mg/dL is the borderline-high level 3. 240 mg/dL and above is the high level of blood cholesterol. A person with this level has more than twice the risk of heart disease compared to someone whose cholesterol is below 200 mg/dL. C. Lowering Cholesterol 1. Lifestyle Changes a. Dietary Changes b. Weight Management c. Physical Activity 2. Medications a. Statins can cut the risk of dying of a heart attack by as much as 40 percent. b. Statins work in the liver to block production of cholesterol. When the liver cannot make cholesterol, it draws LDL cholesterol from the blood to use as a raw material. c. Statins also appear to stabilize cholesterol-filled deposits in artery walls and to cool down inflammation. Chapter 10 – Major Diseases VI. Cardiovascular (Heart) Disease A. Introduction 1. Only one of 2,000 middle-aged Americans meets the criteria for ideal heart health as defined by the American Heart Association. a. These criteria are: i. Never smoked or quit more than a year ago ii. Body Mass index less than 25 iii. Physical Exercise – at least 150 minutes of moderate intensity or 75 minutes of vigorous intensity a week iv. At least four components of a healthful diet v. Total cholesterol lower than 200 vi. Blood pressure below 120/80 vii. Fasting blood sugar below 100 B. How the Heart Works 1. The heart is a hollow, muscular organ with four chambers that serve as two pumps. 2. A human heart is about the size of a clenched fist. 3. Each pump consists of a pair of chambers formed as muscles. a. The upper two—each called an atrium—receive blood, which flows through valves into the lower two chambers—the ventricles—which contract to pump blood out into arteries through a second set of valves. b. The two sides of the heart are separated by a thick wall; they contract at about the same time. Contraction of the ventricles is called systole; the period of relaxation between the contractions is called diastole. 4. The heart valves, located at the entrance and exit of the ventricular chambers, have flaps that open and close to allow blood to flow through the chambers of the heart. 5. The myocardium (heart muscle) consists of branching fibers that enable the heart to contract or beat between 60–80 times per minute. 6. The heart is surrounded by the pericardium, which consists of two layers of tough membrane. 7. The endocardium is a smooth membrane lining the inside of the heart and its valves. Blood circulates through the body by means of the pumping action of the heart. 8. The right ventricle pumps blood to the lungs, where it picks up oxygen and gives off carbon dioxide. a. The blood returns from the lungs to the left side of the heart, which pumps blood, via the aorta, to the arteries and the rest of the body. Chapter 10 – Major Diseases 9. The arteries divide into smaller and smaller branches and finally into capillaries, the smallest blood vessels of all. 10. The blood within the capillaries supplies oxygen and nutrients to the cells and tissues. Blood returns to the heart via the veins. C. Heart Risks on Campus 1. Heart disease is the third-leading cause of death among adults aged 25 to 44. 2. High aerobic fitness in the college-age years has been linked with a lower risk of heart attacks later in life. 3. Certain behaviors put students’ hearts at risk. Binge drinking may hinder the function of blood vessels and increase the risk of stroke, sudden cardiac death, and heart attack. 4. Young athletes face special risks. D. Hearts and Minds: Psychosocial Risk Factors 1. Our psychological and social health affects not just our minds but our bodies. 2. Depression and stress may increase cardiovascular risk; happiness may help keep our hearts healthy. 3. Psychological risk factors for heart disease are classified in three categories, chronic, episodic, and acute. 4. Depression and heart disease often occur together. 5. Anger and hostility have both short- and long-term consequences for the heart, particularly for men. 6. Personality types such as Type D (for distressed); Type A and Type C have been linked to chronic disease such as heart disease and cancer. E. The Heart of a Woman 1. Many people still think of heart disease as a “guy problem.” Men do have a higher incidence of cardiovascular problems than women before age 45, but women’s hearts are also vulnerable. 2. Women need to know the early signs and symptoms of female heart disease: a. Tiredness, even after getting adequate sleep b. Trouble breathing c. Trouble sleeping d. Feeling sick to the stomach e. Feeling scared or nervous f. New or worse headaches g. An ache in the chest h. Feeling “heavy” or “tight” in the chest i. A burning feeling in the chest Chapter 10 – Major Diseases j. Pain in the back, between the shoulders k. Pain or tightness in the chest that spreads to the jaw, neck, shoulders, ear, or the inside of the arms l. Pain in the belly, above the belly button VII. Crises of the Heart A. Coronary Artery Disease 1. Arteriosclerosis is: a. The general term for any impairment of blood flow through the blood vessels or—hardening of the arteries b. The most common form of arteriosclerosis is atherosclerosis, a disease of the lining of the arteries in which plaque narrows the artery channels. c. Plaque is deposits of fat, fibrin, cholesterol, other cell parts, and calcium. B. Atherosclerosis 1. This process begins when LDL cholesterol penetrates the wall of an artery. 2. The body’s own immune cells ingest the LDL then enlarge and rupture releasing the cholesterol into the artery wall. 3. The smooth muscles cells in the artery wall create a fibrous cap over the inflamed area. C. Heart Attack (Myocardial Infarction) 1. The medical name for a heart attack, or coronary, is myocardial infarction (MI). 2. If an artery is blocked by a clot or plaque, or by a spasm, the myocardial cells do not get sufficient oxygen, and the portion of the myocardium deprived of its blood supply begins to die. 3. Although such an attack may seem sudden, usually it has been building up for years. D. Is It a Heart Attack? 1. If they experience the following symptoms, individuals should seek immediate medical care and take an aspirin (325 milligrams) to keep the blood clot in a coronary artery from getting any bigger: a. A tight ache, heavy, squeezing pain, or discomfort in the center of the chest, which may last for 30 minutes or more and is not relieved by rest b. Chest pain that radiates to the shoulder, arm, neck, back, or jaw c. Anxiety d. Sweating or cold, clammy skin e. Nausea and vomiting Chapter 10 – Major Diseases f. Shortness of breath g. Dizziness, fainting, or loss of consciousness 2. If you’re with someone who’s exhibiting the classic signs of heart attack, and if those signs last for two minutes or more, act at once. 3. State-of-the-art treatments for heart attacks include clot-dissolving drugs, early administration of medications to thin the blood, intravenous nitroglycerin, and, in some cases, beta-blockers. VIII. Stroke A. Introduction 1. A stoke occurs when the blood supply to a portion of the brain is blocked. 2. Strokes rank third, after heart disease and cancer, as a cause of death in this country. 3. As many as 80 percent of strokes are preventable, primarily through lifestyle modification. The most important steps are: a. Treating hypertension b. Not smoking c. Managing diabetes d. Lowering cholesterol e. If you’re a woman, taking aspirin (which reduces stroke risk in women but not in men) 4. In a recent study, people who drank either green tea or coffee every day had about a 20 to 30 percent lower risk of having a stroke compared to nondrinkers. B. Risk Factors 1. Gender a. Up to age 85, men have a greater risk of stroke than women. However, women are at increased risk at times of marked hormonal changes, particularly pregnancy and childbirth. 2. Race a. Two to three times greater for blacks than whites. Hispanics also are more likely to develop hemorrhagic strokes than whites. 3. Age a. Risk of stroke more than doubles every decade after age 55. 4. Obesity a. The more overweight individuals are, the more likely they are to have a stroke. Chapter 10 – Major Diseases 5. Hypertension a. Detection and treatment of high blood pressure are the best means of stroke prevention. 6. High Red Blood Cell Count a. Moderate to marked increase in the number of a person’s red blood cells increases the risk of stroke. 7. Heart Disease a. Heart problems can interfere with the flow of blood to the brain and form clots. 8. Blood Fats a. It may be more important to raise HDL than to lower LDL levels. 9. Diabetes Mellitus a. Diabetics have a higher incidence of strokes than non-diabetics. 10. Estrogen Therapy a. Women on estrogen-only therapy significantly increase the risk of stroke. 11. A Diet High in Fat and Sodium a. Individuals consuming the largest amounts of fatty foods and sodium are at much greater risk than those eating low-fat, low-salt diets. 12. Smoking marijuana may double the risk of stroke in young adults. C. Causes of Stroke 1. There are two types of stroke: a. Ischemic stroke, which is the result of a blockage that disrupts blood flow to the brain. i. One of the most common causes of ischemic stroke is the blockage of a brain artery by a thrombus, or blood clot—a cerebral thrombosis. b. Hemorrhagic stroke, which occurs when blood vessels rupture. i. In hemorrhagic stroke, a diseased artery in the brain floods the surrounding tissue with blood. The cells nourished by that artery are deprived of blood and cannot function and blood from the artery forms a clot that may interfere with brain function. Brain tissue, like heart muscle, begins to die if deprived of oxygen, which may then cause difficulty speaking and walking, and loss of memory. Chapter 10 – Major Diseases IX. Cancer A. Overview 1. The uncontrolled growth and spread of abnormal cells causes cancer. 2. Normal cells follow the code of instructions embedded in DNA; cancer cells do not. 3. Abnormal cell divides to create other abnormal cells, which again divide, eventually forming neoplasms (new formations), or tumors. 4. Tumors can be benign (slightly abnormal, but not life threatening) or malignant (cancerous). 5. Without treatment, cancer cells continue to grow, crowding out and replacing healthy cells. This process is called infiltration or invasion. 6. Cancer cells may also metastasize or spread to other parts of the body via the bloodstream or lymphatic system. B. Who Is at Risk? 1. Cancer strikes individuals at all social, economic, and educational levels. 2. In the United States, men have a one in two lifetime risk of developing cancer; for women, the risk is one in three. 3. Heredity a. In some cancers a specific cancer-causing gene is passed down from generation to generation. b. Other people are born with genes that make them susceptible to having certain cells grow and divide uncontrollably, which may contribute to cancer development. c. Genetic tests can identify some individuals who are born with an increased susceptibility to cancer. 4. Racial and Ethnic Groups a. African Americans have the highest rates of fatal cancers. b. Hispanics have a six times lower risk of developing melanoma than Caucasians yet tend to have a worse prognosis than Caucasians when they do develop this skin cancer. c. The incidence of female breast cancer is highest among white women and lowest among Native American women. d. Cervical cancer is most common in Hispanic women. e. Vietnamese men have much higher rates of liver cancer than whites, while Korean men and women are much more likely to develop stomach cancer. f. Compared with other Asian Americans, Chinese and Vietnamese women have higher rates of lung cancer. Chapter 10 – Major Diseases g. Asian Americans who have lived in the United States the longest are likely to develop the cancers that are most common here, such as breast and colon cancer, although at lower rates than whites. 5. Obesity a. Obesity plays a significant role in cancer deaths each year. b. The higher an individual’s BMI, the greater the likelihood of dying of cancer. c. An unhealthy body weight increases the risk of many types of cancer. d. The degree to which extra pounds affect cancer risk varies by the site of the cancer. 6. Infectious Agents a. Worldwide, an estimated 17 percent of cancers can be attributed to infection. b. Among the cancers that have been linked with infectious agents are: i. Human papillomavirus (HPV) with cancer of the cervix, mouth, and throat, vulva, and anus. ii. Helicobacter pylori with stomach cancer. iii. Viruses with certain leukemias (cancers of the blood system) and lymphomas (cancers of the lymphatic system), cancers of the nose and pharynx, and liver cancer. iv. Human immunodeficiency virus (HIV) with certain lymphomas and leukemias and a type of cancer called Kaposi’s sarcoma. C. Common Types of Cancer 1. Cancers are classified according to the type of cell and the organ in which they originate, such as the following: a. Carcinoma i. The most common cancer which starts in the epithelium b. Sarcoma i. Forms in the supporting or connective tissues in the body c. Leukemia i. Begins in the blood forming tissues d. Lymphoma i. Arises in the cells of the lymph system 2. Skin Cancer a. One in every five Americans can expect to develop skin cancer in his or her lifetime. b. Young men and women who use tanning beds are significantly more likely than nonusers to develop early-onset basal cell skin cancers before age 40. Chapter 10 – Major Diseases c. The most common types of skin cancers are basal cell and squamous cell. d. Malignant melanoma, the deadliest type of skin cancer, causes 1 to 2 percent of all cancer deaths. i. Individuals with the following characteristics are at an increased risk for melanoma: (a) Fair skin, light eyes, or fair hair. (b) A tendency to develop freckles and to burn instead of tan. (c) A history of childhood sunburn or intermittent intense sun exposure. (d) A personal or family history of melanoma. (e) A large number of nevi, or moles, or dysplastic moles. e. Detection of Melanoma i. The most important early indicators are change in color, an increase in diameter, and changes in the borders of a mole. f. Treatment. i. When caught early, it is highly curable. Treatment may include surgery alone or may include chemotherapy to shrink it. 3. Breast Cancer a. Common risk factors include: i. Age ii. Family history iii. Long menstrual history iv. Age at birth of first child v. Breast biopsies vi. Race and ethnicity vii. Occupation viii. Alcohol ix. Smoking x. Hormone therapy xi. Obesity xii. Sedentary lifestyle. b. Screening for Breast Cancer i. Monthly self-breast exam (BSE) after their periods. ii. Breast exam by trained practitioner every one to three years, depending on age. iii. Mammograms for women starting at age 40. iv. The best tool for early detection is the diagnostic X-ray exam called a mammography. Chapter 10 – Major Diseases c. Treatment i. Treatment options include surgery, radiation, and drugs—either alone or in combination. ii. Lumpectomy is surgery which removes only the cancerous tissue and surrounding margin of normal tissue. iii. Mastectomy is surgery which removes the entire breast and some of the underarm lymph nodes. iv. Radiation therapy is treatment with high-energy rays or particles to destroy cancer. v. Chemotherapy is the use of drugs. 4. Cervical Cancer a. This is the second most common cancer in women worldwide. b. Other risk factors include sexual activity before the age of 16 or have had multiple sex partners, genital herpes, and smoking or significant exposure to secondhand smoke. c. HPV infection is the primary risk factor for cervical cancer. d. Doctors no longer recommend annual Pap test because it generally takes 10 to 20 years for cervical cancer to develop and overly frequent screening could lead to unneeded medical and surgical problems. 5. Ovarian Cancer a. This is the leading cause of death from gynecological cancers. b. Risk factors for ovarian cancer include family history of ovarian cancer, personal history of breast cancer, obesity, infertility, and low levels of transferase. c. Ovarian cancer may be diagnosed by pelvic examination, ultrasound, MRI, computed tomography, or PET (positron emission tomography) scan. d. Symptoms that are often overlooked are abdominal pain, feeling full quickly after eating, and urinary urgency. 6. Testicular Cancer a. The incidence of testicular cancer is rising, while occurring mostly in young men between the ages of 18 and 35, with those men with an undescended testicle at highest risk. b. Symptoms my include a slight enlargement of one testicle, different sensation to touch, lumps on the testicle, a dull ache in the lower abdomen or groin, along with a sense of heaviness or sluggishness. c. Self-testicular exams are important to detect any problems. d. Treatment generally involves surgery, radiation therapy, chemotherapy, and the removal of nearby lymph nodes. Chapter 10 – Major Diseases 7. Colon and Rectal Cancer a. This is the third most common cancer and accounts for 10 percent of cancer deaths. b. Risk factors include being over 50 years of age, personal or family history of colon and rectal cancer, polyps in the colon or rectum, ulcerative colitis, smoking, alcohol consumption, prolonged high consumption of red and processed meat, high-fat, or low-fiber diets and inadequate intake of fruits and vegetables. c. Early symptoms include bleeding from the rectum, blood in the stool, or a change in bowel habits. d. A colonoscopy is recommended beginning at age 50, earlier for those at higher risk based on personal, family, or medical history. e. Treatment may include surgery, radiation therapy, and/or chemotherapy. 8. Prostate Cancer a. After skin cancer, prostate cancer is the most common form of cancer in American men. b. The risk of prostate cancer increases with age, family history, exposure to the heavy metal cadmium, a high number of sexual partners, a history of frequent STIs, and a possible inherited predisposition. c. An annual PSA test is no longer recommended. X. Infectious Diseases A. Overview 1. Infection is a complex process. a. Pathogens, (disease causing organisms), trigger infections which are countered by the body’s own defenders. b. Host, either a person or a population that contacts one or more agents in an environment. c. Vector – a biological or physical vehicle that carries the agent to the host and provides the means of transmission. B. Agents of Infection 1. Viruses are the tiniest pathogens but the toughest, consisting of a nucleic acid with a protein coat. a. The most common viruses types; i. Rhinoviruses and adenoviruses ii. Coronaviruses iii. Influenza viruses iv. Herpes viruses v. Papillomaviruses Chapter 10 – Major Diseases vi. Hepatitis viruses vii. Slow viruses viii. Retroviruses ix. Filoviruses 2. Antibiotics – drugs that inhibit or kill bacteria, have no effect on viruses. 3. Antiviral drugs do not completely eradicate a viral infection, although they can decrease its severity and duration. 4. Bacteria are simple one-celled organisms, but are the most plentiful microorganisms as well as the most pathogenic. a. Most bacteria do not cause disease, but play an important role in our bodies. However, some bacteria can get out of control, causing urinary tract infections and vaginal infections. b. They can harm the body by releasing enzymes that digest body cells and cause illnesses. c. Most bacterial infections can be treated with an antibiotic. 5. Fungi are single-celled or multicelled organisms that consist of threadlike fibers and reproductive spores. a. Athlete’s foot is a type of fungi. b. Treatment consists of antifungal drugs. 6. Protozoa are single-celled, microscopic animals that release enzymes and toxins that destroy cells or interfere with their function. a. Not a major health problem in this country, primarily because of public health measures. 7. Helminths (parasitic worms) are small parasitic worms that attack specific tissues or organs and compete with the host for nutrients. C. How Infections Spread 1. Animals and insects can spread a variety of diseases. 2. People can transmit pathogens through the air, through touch, and through sexual contact. 3. Food that is undercooked or inadequately washed can have bacteria that cause disease. a. Escherichia coli (E coli) and Salmonella are bacteria that can cause serious infections. 4. Water diseases are still widespread in underdeveloped parts of the world but uncommon in the United States. D. The Process of Infection 1. If someone infected with the flu sits next to you on a bus and coughs or sneezes, tiny viral particles may travel into your nose and mouth. 2. Immediately, the virus finds or creates an opening in the wall of a cell, and the process of infection begins. Chapter 10 – Major Diseases 3. Incubation period is the time between invasion and the first symptom. 4. Prodromal period is the early stage of the battle between your body and the invaders. 5. Recovery begins when the body’s forces gain the advantage. E. Who Develops Infections? 1. Children and Families. Youngsters get up to a dozen colds annually; adults average two a year. Parents get up to six times as many colds as other adults. 2. The elderly. People 65 years or older who get the flu have a 1 in 10 chance of being hospitalized for pneumonia or other respiratory problems, and a 1 in 50 chance of dying from the disease. 3. The chronically ill. Lifelong diseases decrease an individual’s ability to fend off infections. 4. Smokers and those with respiratory problems are at high risk for respiratory problems. 5. Those who live or work in close contact with someone sick face greater odds of catching cold and flu. 6. Residents or workers in poorly ventilated buildings. Building technology has helped spread certain airborne illnesses via recirculated air. XI. How Your Body Protects Itself A. Introduction 1. Immunity is protection from infectious disease by various parts of your body. 2. Lymph nodes or glands are small tissue masses in which some protective cells are stored. 3. Antigen is any substance the white blood cells recognize as foreign. 4. Active immunity – the body makes its own antibodies. 5. Passive immunity – is produced by the injection of gamma globulin, the antibody-containing part of the blood, from another person. B. Immune Response 1. When an antigen enters the body, the T cells aided by macrophages engage in combat with the invader. 2. Certain T cells (cytotoxic T cells) can destroy infected body cells or tumor cells by “touch-killing.” 3. Meanwhile, the B cells churn out antibodies, which rush to the scene and join in the fray. 4. Also busy at surveillance are natural killer cells that, like the elite forces of a SWAT team, seek out and destroy viruses and cancer cells. 5. Inflammation is redness, swelling, local warmth, and pain. Chapter 10 – Major Diseases 6. Abscess is a localized accumulation of pus and disintegrating tissue. 7. Systemic disease is a pathologic condition that spreads throughout the body. 8. Immune deficiency is partial or complete inability of the immune system to response to pathogens. 9. Allergy represents a hypersensitivity to a substance in the environment or diet that does not bother most other people. C. Immunity and Stress 1. Stress affects the body’s immune system in different ways, depending on two factors: the controllability or the uncontrollability of the stressor and the mental effort required to cope with the stress. XII. Immunization for Adults A. Immunization has reduced cases of measles, mumps, tetanus, whooping cough, and other life-threatening illnesses by more than 95 percent. B. Although many people associate vaccination with children’s health, the vast majority of vaccine-preventable deaths occur among adults. XIII. Upper Respiratory Infections A. Common Cold 1. There are more than 200 distinct cold viruses. 2. Colds can strike in any season, but different cold viruses are more common at different times of the year. a. Rhinoviruses cause most spring, summer, and early fall colds and tend to cause more symptoms above the neck (stuffy nose, headache, runny eyes). b. Adenoviruses, para-influenza viruses, coronaviruses, influenza viruses, and others that strike in the winter are more likely to get into the bronchi and trachea (the breathing passages) and cause more fever and bronchitis. 3. Cold viruses spread by coughs, sneezes, and touch. 4. Antibiotics have no effect against viruses and may make your body more resistant to such medications when you develop a bacterial infection in the future. B. Preventing Colds 1. Taking vitamin C ever day does not ward off the common cold or shorten its length or severity. 2. Lozenges or syrup containing zinc, a mineral that inhibits rhinoviral replication, did help reduce the duration and severity of the common cold in healthy people when taken within 24 hours of onset of symptoms. Chapter 10 – Major Diseases 3. Antibiotics are effective only against bacteria. Antibiotics can foster the growth of one or more strains of antibiotic-resistant bacteria. C. Influenza 1. Similar to a cold, influenza—or the flu—causes more severe symptoms that last longer. 2. Flu viruses, transmitted by coughs, sneezes, laughs, and even normal conversation, are extraordinarily contagious, particularly in the first three days of the disease. 3. Two varieties of viruses—influenza A and influenza B—cause the most flus. 4. The CDC recommends an annual flu shot for everyone over the age of six months, except for those with certain medical conditions. 5. H1N1 Influenza (Swine Flu) a. The symptoms of HINI (Swine Flu) are similar to the symptoms of regular flu: fever, cough, sore throat, body aches, headaches, chills, fatigue. XIV. Meningitis A. Overview 1. An invasive meningococcal disease that attacks the membranes around the brain and spinal cord and can result in hearing loss, kidney failure, and permanent brain damage. 2. If not treated early, meningitis can lead to death or permanent disabilities. 3. Meningitis spreads through the exchange of respiratory droplets, which can come from sharing a drink, cigarette, or silverware; kissing; coughing; or sneezing. Even inhaling secondhand smoke can infect you with the disease. 4. Preventing Meningitis a. Vaccination is recommended for all American adolescents, with initial immunization at age 11 or 12 and a booster at age 16. b. Vaccination protects against four of the five most common types of meningococcal bacteria. 5. Recognizing Meningitis – The most common symptoms of meningitis are: a. Sudden high fever b. Severe, persistent headache c. Neck stiffness and pain d. Nausea and vomiting e. Confusion and disorientation f. Drowsiness and sluggishness g. Eye pain or sensitivity to bright light Chapter 10 – Major Diseases h. Pain or weakness in muscles or joints i. Abnormal skin color j. Stomach cramps k. Ice-cold hands and feet l. Dizziness m. Reddish or brownish skin rash n. Numbness and tingling o. Seizures 6. When to Seek Medical Care a. If two or more symptoms appear together or suddenly, seek treatment immediately. XV. Hepatitis A. Overview 1. An estimated 500,000 Americans contract hepatitis each year and the number of hepatitis-related deaths have been rising in the last decade. 2. There are at least five different viruses referred to as hepatitis. A, B, C, Delta, and E can cause this inflammation of the liver. B. Hepatitis A 1. A less serious form and is usually transmitted by poor sanitation 1. Less common in industrialized nations than in developing countries. 2. Common among men who sleep with men and among people who use illegal drugs. C. Hepatitis B 1. It is a potentially fatal disease and is transmitted through the blood and other bodily fluids. 2. Once spread mainly by contaminated tattoo needles, needles shared by drug users, or transfusions of contaminated blood, hepatitis B is now transmitted mainly through sexual contact. 3. It can cause chronic liver infection, cirrhosis, and liver cancer. D. Who Develops Hepatitis? 1. People at a higher risk are those with multiple sex partners, athletes in contact sports, male homosexuals, infants born to infected mothers, injection drug users, and health-care workers in frequent contact with blood. E. Hepatitis C 1. Hepatitis C virus (HCV) is four times as widespread as HIV, infecting about 1 percent of Americans. 2. It can be detected by a simple blood test; however, very few of the infected realize they are infected. Chapter 10 – Major Diseases 3. 80 percent have no symptoms. 4. Risk factors for HCV infection are blood transfusion or organ transplant before 1992; exposure to infected blood; illegal drug use; tattoos or body piercing. 5. About three-quarters of those infected with HCV develop chronic or longterm hepatitis. 6. The most common treatment is a combination of interferon and ribavirin. XVI. Insect- and Animal-Borne Infections A. Introduction 1. Lyme disease a. The most commonly reported vector-borne infectious disease in the United States. b. This bacterial infection is spread by ticks carrying a particular bacterium. c. What you need to know: i. Symptoms include joint inflammation, heart arrhythmias, blinding headaches, and memory lapses. The disease can also cause miscarriages and birth defects. ii. You are not likely to get Lyme disease if a tick is attached to your skin for less than 48 hours. iii. About 70 to 80 percent of infected individuals develop a red rash at the site of the tick bite. iv. Once diagnosed, Lyme disease is treated with antibiotics. 2. West Nile virus (WNV) a. Transmitted by mosquitoes that feed on an infected bird and then bite a human. b. Things to remember: i. WNV interferes with the normal central nervous system functioning and causes inflammation of the brain tissue. ii. The risk of catching it is low. iii. Repellents that contain an EPA-registered insect repellent can protect against these mosquitoes. iv. There is no specific treatment. 3. Avian influenza a. Commonly known as bird flu b. Caused by viruses that occur naturally in birds and does not usually affect humans Chapter 10 – Major Diseases B. The “Superbug” Threat: MRSA 1. When the bacterium Staphylococcus aureus became resistant to penicillin, physicians switched to a newer antibiotic, methicillin. 2. Methicillin-resistant S. aureus (MRSA) enters the body through a scrape, burn, or surgical incision. 3. MRSA poses the greatest danger to athletes in contact sports, the elderly, babies, and individuals who have undergone surgery, taken antibiotics, or have a weakened immune system, preexisting infection, open wounds, cuts, burns, or other types of wounds, such as skin breaks from an intravenous drug line. Key Terms angina hypertension antibiotics immune deficiency antiviral drug immunity aorta incubation period arteriosclerosis infiltration atherosclerosis inflammation atrium influenza bacteria insulin resistance capillary lipoprotein cardiometabolic lumpectomy cholesterol Lyme disease diabetes mellitus lymph nodes diastole mammography diastolic blood pressure mastectomy fungi meningitis gamma globulin metabolic syndrome helminth metastasize hepatitis myocardial infarction (MI) host pathogen Chapter 10 – Major Diseases plaque systolic blood pressure prediabetes systemic disease prehypertension triglyceride protozoa vector stroke ventricle systole virus Chapter 10 – Lowering Your Risk of STIs and Other Infections