Bbh 440 final study guide PDF

Preview

Summary

Download Bbh 440 final study guide PDF

Description

Study Guide for Final Exam

Epidemiology ●

● ●

The occurrence in a community or region of cases of illness, specific health-related behavior, or other health-related events clearly in excess of normal expectancy. The community, region, and period are specified precisely. Epidemiology is the study of the distribution and determinants of disease in populations, and part of its province is the study of the related social and behavioral factors. Epidemiology is the study of the distribution and determinants of health-related states or events in human populations, and the application of this study to prevent and control health problems

Descriptive vs. analytic epidemiology ●

●

Descriptive epidemiology involves characterization of the distribution of health-related states or events by, WHO, WHERE, WHEN ○ Person - who ○ Place - where ○ Time – when ○ Clinical criteria - what Analytic epidemiology involves identifying and quantifying associations, testing hypotheses, and identifying causes of health-related states or events, WHY/HOW

Definitions ○

Endemic: The ongoing, usual, or constant presence of a disease in a community or population. Ex. Chicken pox in US, malaria in Africa ○ Epidemic: The occurrence of illnesses in a community clearly in excess of normal expectancy ○ Pandemic: An outbreak of a disease of exceptional proportions… spreading quickly from one region to another. ○ Epizootic: An outbreak (epidemic) of disease in an animal population (often with the implication that may affect human populations) ○ Reservoir: habitat in which the agent lives, grows, and thrives ○ Agent: causal factor that produce disease and health problems in populations ○ Host: intrinsic (within the organism) factors that influence susceptibility, exposure, or response to agents ○ Environment: extrinsic (external to organism) factors that influence the existence of agent, exposure, or susceptibility to agent Common source: particular source ● Point source: contamination is fixed ● Intermittent: source varies by place or time ● Continuous: source contamination is continuous ○ Propagated – Arise from infections being transmitted from one infected person to another ex.) TB, measles, influenza etc. ■ Host to host ■ Through direct or indirect routes ○ Mixed – ■ When a common source epidemic is followed by person-to-person contact and disease is spread as a propagated outbreak ■ Ex. Shigellosis occurred among a group of 3000 women attending a music festival. Over the next few weeks, subsequent generations of shigella cases spread by person-to-person transmission from festival attendees ○

Neither

■ ■

May be non-human-to-human via vector Lyme disease, West Nile virus

Disease transmission ●

●

Direct ○ Person-to-person contact: ex. Kissing, sex, etc. ○ Droplet spread: sneezing, coughing Indirect ○ Vehicle-borne ○ Fomite-borne: specific type of vehicle that is an inanimate object or surface like doorknobs, clothing, etc. ○ Vector-borne ■ Invertebrate animal that transmits disease ○ Airborne ■ Carried by dust suspended in air.

Agent characteristics ● ●

● ● ● ● ● ●

Infectivity- The capacity of an agent to cause infections (i.e., to infect the host). Pathogenicity- The capacity of infectious agents to cause disease in the host (i.e., to cause clinically apparent disease). Pathogenicity should not be confused with virulence (which is the degree of pathology caused by the agent). Virulence- The capacity of an infectious agent to produce a high degree of pathology; usually indicating a severe or fatal illness. A “virulent” disease has a high case fatality ratio (CFR). Toxigenicity- The capacity of an infectious agent to produce a toxin or a poison. The toxin is usually the mechanism in which the agent is harmful or causes a disease. Resistance- The capacity of an infectious agent to survive adverse environmental conditions (e.g., use of antibacterial cleaning agents, temperature, etc.). Immunogenicity- The capacity of an infectious agent to induce a local or systemic immunity in a host (immunogenicity) through production of antibodies (antigenicity). Incubation time- The time period between the exposure to the infectious disease agent and the first appearance of clinical signs for the disease. Generation time- With person-to-person spread, the interval of time between the receipt of infection by the host and the maximal communicability of that host. Not the same as incubation time (time to apparent clinical effects). The generation time may be shorter than incubation time (e.g., mumps).

Incubation VS. Induction ● ● ●

Incubation period: (infectious diseases) The time period between the invasion of the infectious agent and the first appearance of a symptom or sign of the disease. Induction period: (chronic non-infectious diseases) the time required for a causal factor to produce a disease. The interval from the causal action of the factor to the initiation of the disease. PROBABLE DATE OF COMMON EXPOSURE ■ Outbreak of hepatitis A ■ the first case, August 21st; the peak number of cases on September 3rd; last case on September 13th. ■ Question: What was the probable date of the common exposure? ■ Answer: Use the average incubation period (28 days) and count back from peak occurrence. This is the probable date of common exposure (= August 6th) ● PROBABLE PERIOD OF EXPOSURE ● Outbreak of hepatitis A ● The first case, August 21st; the peak number of cases on September 3rd; last case on September 13th. ● Question: What is the period of exposure?

●

Answer: Use the range of the incubation period (15-50 days); Count back 15 days from the first case and 50 days from the last case. This provides the probable exposure period (July 24th – August 6th)

Natural History ●

●

●

General staging ■ Stage of susceptibility - exposure, risk factors ● Primary prevention - alter exposure that leads to disease ■ Stage of presymptomatic (subclinical) disease - pathological changes, onset of symptoms ● Secondary prevention - detect and treat pathological process at an earlier stage ■ Stage of clinical disease - usually time of diagnosis ● Secondary or tertiary ■ Stage of recovery, disability, or death ● Tertiary prevention - prevent relapse and further deterioration via follow-up care and rehab ■ Prevention intervention- recognize primary, secondary, and tertiary individual and population level intervention Infectious disease staging ■ Inoculation point - Time of infection ■ Incubation period - Time between infection and symptoms ■ Prodromal point - Appearance of first symptoms ■ Prodromal period - Time of increasing symptoms/illness ■ Differential point - Easiest time of diagnosis ■ Fastigium period - Maximum severity or intensity ■ Defervescence period - Symptoms are declining ■ Convalescent period - Recovery period, usually feeling better ■ Defection period - Pathogen is killed off or in remission Types of carriers: ■ Active: harbors disease causing organism and has done so for some time, even though they may not have recovered from the disease ■ Healthy/passive/true: harbors and can spread pathogen but is not ill and never shows symptoms of disease ■ Incubatory: harbors and can spread the agent while in the incubation period of disease (not showing symptoms until later as illness develops) ■ Convalescent: harbors and can spread the agent after the clinical symptoms have disappeared

●

Screening ○ NOT a diagnosis; used to identify disease in asymptomatic people ○ Secondary prevention ○ During detectable preclinical phase (DPCP)

●

Requirements for a screening program ■ Suitable disease - cancer, heart disease, STI’s, tuberculosis ■ Suitable test ■ Suitable program ■ Good use of resources

●

Screening test possible outcomes: ● true positive: when it says positive, and it’s actually positive ● false positive: when it says positive but it’s actually negative ● true negative: when it says negative and it is negative ● false negative: when it says negative, but it’s actually positiv

Calculations

●

●

●

●

Sensitivity - tells how well a test detects disease (denominator related to disease) ○ fraction of people diseased who test positive, ○ “if a person has the disease, how often will the test be positive?” ○ TP/(TP+FN) Specificity: how well a test identifies non disease ○ if a person does not have the disease, how often will the test be positive? ○ TN/(FP+TN) PPV= proportion of people with positive tests who truly have the disease ○ TP/(TP+FP) ○ HEAVILY affected by prevalence ○ Denominator related to test status (+ or -) NPV= proportion of negative tests who truly do not have the disease ○ TN/(TN + FN)

Likelihood ratios: positive, negative, and how to interpret value ●

●

Likelihood ratio= odds of having a disease following a positive or not having a disease following negative test ○ “What is the likelihood of this being right?” ○ Likelihood ratio > 1= increases probability of having the disorder ○ Likelihood ratio H. Risk factors (uncontrollable)

a. Age b. Sex c. Race d. Genetics (family history) i. Not straightforward or simple ii. Genetics alone is not sufficient, requires environment iii. Type 1 1. Less of genetic basis 2. Need to inherit from both parents 3. Environmental triggers may include cold weather, viruses, etc. iv. Type 2 1. Stronger link to family history 2. Difficult to differentiate lifestyle factors from genetic susceptibility (obesity) I. Risk factors (controllable) A. Weight (obesity) & physical inactivity B. Smoking C. Sleep loss v. greater sleep loss = less insulin release vi. increases cortisol which increases blood glucose and interferes with insulin function vii. increases appetite and hunger and reduces satiety viii. Results in less regular exercise J. Diabetes Prevention Program 1. Objective: To examine if modification of risk factors for diabetes using a lifestyle-intervention program or administration of medication (metformin) would prevent or delay the development of diabetes 2. Methods: participants assigned to 1 of 3 arms: a. General advice + placebo (2x daily) b. General advice + medication (2x daily) c. Intensive behavior change i. Weight loss goal >7% body weight through healthy diet and physical activity of moderate intensity >150 minutes per week ii. Results: both medication and behavior change reduced risk of diabetes compared to placebo 1. Both medication and behavior change reduced risk of diabetes compared to placebo 2. Behavior change had greater effect than medication 3. Indicated that type 2 diabetes risk can be reduced by behavioral changes A. Complications a. CVD i. Having diabetes increases risk for CAD ii. The incidence of stroke is 2-6 times higher among men and women with diabetes than those without diabetes iii. Diabetes accelerates atherosclerosis b. Kidneys i. Blood vessels in kidneys damaged over time ii. Can lead to kidney failure iii. May require dialysis in severe cases c. Vision i. Leading cause of new cases of blindness ii. Each year 12k-24k people blind due to retinopathy

d. Neuropathy i. Damage to blood vessels that supply nerves causes loss of sensation ii. Neuropathy is progressive iii. Increased risk of feet injuries iv. Increased risk of amputations B. Screening & Treatment a. American Diabetes Association recommendations: i. Every 3 years starting at age 45 ii. Before age 45 and more frequently if risk factors are present b. Treatment i. No known cure ii. Lifestyle (diet, exercise, sleep) iii. Glucose monitoring iv. Medication

Cancer ● ●

● ●

●

●

●

Characterized by uncontrolled cell proliferation (growth) and potential spread Tumor/neoplasm = any abnormal growth of cells ○ Benign = non cancerous ○ Malignant = cancerous ○ Metastasis = spread of malignant cells ■ Circulatory ■ Lymphatic Second leading cause of death Types ○ carcinoma: most commonly diagnosed (originate in skin, lungs, breasts, other organs) ○ sarcoma: originate in bone, muscle, fat, and cartilage ○ lymphoma: cancer of the lymphocytes ○ Leukemia:cancer of the blood Cancer Staging ○ Stage 0: cancer in situ (in tissue of origin) ○ Stage I: localized ○ Stage II: more advanced, spread to lymph nodes and nearby tissue ○ Stage III: advanced spread to lymph nodes and surrounding tissue ○ Stage IV: metastasized to other organs or throughout the body Cancer Survival Rate - 5 years ○ Includes cancer survivors who are disease free, under treatment, or in remission ○ More commonly used to judge progress in cancer treatments (early detection programs) ○ Highly influenced by stage at diagnosis ○ Good cancer: thyroid, testes, prostate, melanoma, and breast ○ Bad cancer: pancreas, liver, esophagus, lung & bronchus, stomach Survival rates: ○ Based on biological differences ■ Susceptibility, genetic makeup ○ Differential access to treatment ■ SES ■ lack of insurance ○ Differential use of screening (later diagnosis at later stages)

●

●

●

●

●

●

●

■ fear of misunderstanding ■ Cultural ■ socialization Cancer Susceptibility: ○ Age - higher age = higher risk ○ Race - african american men at the highest risk overall; african american women the least ○ Sex - males at an increased risk Genetics: 5-10% of cancers have clear genetic basis ○ Family history of cancer suggests a predisposition to cancer ■ BRCA1 and BRCA2 (breast cancer gene) Carcinogens: cancer-causing agents ○ Lifestyle related examples: tobacco, alcohol, obesity, diet, and physical inactivity ○ Occupation/environment: asbestos, benzene, radiation ○ WHO risk factors ■ Category 1: sufficient evidence for a causal relationship with cancer in humans Global Cancer Statistics: ○ 2012: 14 million new cases of cancer and 8.2 cancer-related deaths ○ Annual cases expected to rise to 22 million by 2032 ○ 33% of cancer deaths related to the BIG 5 risks: ■ Low fruit and vegetable intake ■ Lack of physical activity ■ High BMI ■ Alcohol use ■ Tobacco use ○ Over 60% of new cases and 70% of global cancer deaths occur in Africa, Asia, and Central/South America Screening: ○ Screening is not a diagnosis ○ Can be universal or selective ○ Methods depend on cancer type ○ Screening is most effective for frequent cancer types for which screening tests are: ■ Cost-effective ■ Affordable, acceptable, accessible ■ Available to the majority Treatment: ○ Depends on location and stage ○ surgery, chemo, radiation, hormone therapy, immunotherapy ○ Future treatments: anti-cancer vaccines; gene therapy Prevention ○ Tobacco use/Heavy alcohol use: all related can be completely preventable ○ Obesity/physical activity: 1/3 of cancer cases are preventable ○ Infectious agents - (HPV, hepatitis B/C, HIV, H. pylori) many related cancers could be avoided by preventing infection (behaviors or vaccine) or treating them ○ Sun exposure/indoor tanning - many skin cancer cases should be prevented by covering skin and avoiding tanning

Parkinson’s and Alzheimer's a.

Cognitive Health

Cognition - the ability to think, learn, and remember Cognitive health continuum - ranges from “optimal functioning” (ability to learn new things) to severe disability (dementia) iii. Linked to brain health (physiologic) b. Normal cognitive aging i. Small cognitive abilities decline, which do not normally result in impairment ii. Speed of processing, making decisions, remembering may decline c. Cognitive impairment i. Difficulty with cognitive process that affect everyday life ii. Spans wide range of functioning iii. Can occur as a result of Alzheimer’s, dementia, stroke, traumatic brain injury iv. Dementia 1. Decline in mental ability severe enough to interfere with daily life 2. Not a specific disease 3. Not normal aging 4. Caused by damage to brain cells from disease or trauma 5. Many dementias are progressive d. Neurodegenerative diseases i. Involve degeneration and death of neurons ii. No cure e. Parkinson’s i. History: 1. Symptoms described in ancient historical texts 2. James Parkinson published first description in 1817 3. L-DOPA began to be used clinically in 1967 ii. Epidemiology 1. 14th leading cause of death 2. 2nd most common neurodegenerative disease 3. ~1 million people in US affected 4. 60 = average age of onset iii. Symptoms – know definitions of 4 cardinal symptoms 1. Tremors 2. Bradykinesia: slowness of movement and is one of the cardinal manifestations 3. Rigidity 4. Impairment of posture iv. Characterized by loss of dopamine neurons 1. Substantia nigra most affected 2. Abnormal aggregates of proteins known as Lewy bodies v. Prognosis and causes of death 1. Variable: a. Age of onset is a good predictor of how quickly disease progresses 2. Aspiration pneumonia, choking, falls vi. Risk factors: age, sex, genetics 1. Age is the biggest risk factor 2. Gender: males more affected 3. Race: hispanics and whites more affected 4. Genetics play a role in some cases 5. Environmental triggers (exposure to certain toxins or head trauma) Screening and prevention vii. i. ii.

viii.

f.

Sleep

Treatments 1. L-DOPA: precursor to dopamine that the brain cause use to synthesize more dopamine a. Mechanism and shortcomings i. Loses effectiveness and long-term use increases risk of developing movement problems 2. Deep brain stimulation: involves implanting an electrode in the brain a. Can help manage symptoms Alzheimer’s i. History 1. Old age = dementia 2. Since ancient history 3. Alois Alzheimer identified first case in early 1900’s 4. 20th century = applicable to any age group with characteristic symptoms ii. Epidemiology 1. 6th leading cause of death 2. Leading cause of neurodegenerative disease 3. 1 in 9 people age 65 and over iii. Symptoms 1. AD is a form of dementia 2. Early symptoms: memory problems: encoding new info = most affected 3. Later symptoms: memory loss, communication problems, loss of mobility, weight loss, incontinence, unusual behavior, etc. 4. Complete dependency rises later on iv. Pathophysiology 1. Widespread loss of neurons in brain and brainstem 2. Associated with protein misfolding and accumulation a. Abnormally folded Beta-amyloid proteins accumulate in extracellular plaques b. Abnormally folded Tau protein accumulation in neurofibrillary tangles v. Prognosis and causes of death 1. Average life expectancy after diagnosis = 6 yrs 2. Death due to causes: a. Pneumonia (⅔ of cases) b. Ability to cope w/ other infections = impaired c. Fatal blood clots due to bedridden vi. Risk factors: 1. Unmodifiable: a. Age is the greatest predictor b. Gender: females affected more c. Race: black and hispanics affected more d. Genetics play a role in some cases 2. Modifiable: severe traumatic brain injury vii. Screening and prevention 1. Can only be definitively diagnosed after death viii. Treatment – mainly Acetylcholinesterase inhibitors 1. Most common treatment for AD 2. Inhibit breakdown of acetylcholine 3. Don’t slow disease progression; only modest improvements in cognition

● ●

●

Sleep as a dynamic biological and behavioral state during which many processes vital to health and well being occur Known functions of sleep ○ Energy conservation ○ Restoration and repair/physical growth ○ Brain changes ■ Memory consolidation ■ Active forgetting ■ Flushing of the brain by the glymphatic system Determinants of sleepiness, alertness, and performance – know these and examples of each ○ Biological time of day (circadian rhythm) ■ Circadian clock is located in the brain and regulates daily rhythms ■ Example output rhythms – know specifics of when these rhythms rise and fall ● Melatonin – sleep promoting hormone that rises in the evening, peaks at night and is suppressed by light ● Core body temperature lowest at night when asleep ● Cortisol - hormone related to stress; peaks in the morning ● Circadian rhythm of sleepiness: peak...