Ch 9: Environmental and Nutritional Diseases Flashcards
What is the “Global Disease Burden”?
It estimates the burden imposed by environmental dz
What is “Disability adjusted life year” (DALY)?
Sum of years of life LOST due to premature mortality and disability in a population.
Describe the prevalence of HIV/AIDS between 1990s and now.
There have been large increases in mortality due to HIV/AIDS since the 1990s.
What is the single leading global cause of health loss (morbidity + premature death)?
Undernutrition
What is the leading cause of death in developed countries?
Ischemic heart and cerebral vascular disease
How prevalent is infectious disease in developing countries? Name the most common ones.
5/10 leading causes of death are infectious diseases.
Respiratory infections HIV/AIDS Diarrheal diseases TB Malaria
In the postnatal period, ~50% of all deaths in kids younger than 5 are attributed to 3 conditions. What are they?
pneumonia
diarrheal dz
malaria
Describe some changing trends in GBD.
Increasing Cardiovascular disease, cancer, HIV
Decreasing diarrheal dz and neonatal conditions
Name the categories of emerging infectious dz and give examples.
Newly evolved strains/organisms (ex: multi drug resistant TB, chloroquine-resistant malaria, MRSA)
Pathogens endemic to other species that recently jumped to human populations (ex: HIV)
Pathogens that have been present in human pop, but show recent increase in incidence (ex: dengue fever - due to warming spread to southern US)
What is poised to become the global leading cause of environmental disease?
Climate change
Climate change has serious negative impact on human health by increasing incidence of dz. Name a couple and why they are becoming more prevalent.
Cardiovascular, cerebrovascular, and respiratory dz = worsened by heatwaves and air pollution
Gastroentritis, cholera, food borne and waterborne infectious dz = contamination from floods and disruption of clean water supplies
Vector-borne infectious dz = malaria, Dengue fever = due to increasing temp, crop failures
Malnutrition = due to crop failure
Define toxicology.
distribution, effects, and mechanisms of action of toxic agents
physical agents = radiation, heat
What is poison dependent on?
dosage!
all substances are poisons - the right dosage differentiates poison from remedy
Define Xenobiotics.
exogenous chemicals in environment that may be absorbed into body
What is characteristic of xenobiotics that helps them be absorbed easily?
They are lipophilic - facilitates transportation and penetration through basement membrane
What 2 things happen to xenobiotics in the body?
Metabolized to inactive water-soluble product = detoxification
Activated to form toxic metabolites
What enzyme family makes xenobiotics toxic? Can they also detoxify? If so, how?
CYP450
Detoxification through 2 phases:
1) chemicals undergo hydrolysis, oxidation, or reduction
2) products of phase 1 converted to water-soluble compounds through glucoronidation, sulfation, methylation, and conduction with glutathione
Where is the CYP450 enzyme system found?
Primarily ER of liver
but also sin, lungs, GI
What is the more common action of CYP450?
Detoxification
Less common = converting xenobiotics into active compounds
Will both mechanisms of CYP450 cause cell injury? Explain.
Yes, because both produce ROS as a byproduct
What does CYP450 metabolize carbon tetrachloride into? What other compounds does it metabolize?
It converts the dry cleaning agent into a toxic trichlozomethyl free radical
Also metabolizes acetaminophen, barbiturates, warfarin, alcohol, and anticonvulsants.
What are the pollutants associated with OUTDOOR air pollution?
Sulfur dioxide Carbon monoxide Ozone Nitrogen dioxide Lead Particulate matter (soot)
Who are affected by OZONE and what are the effects?
Healthy adults and children = decreased lung function, increased airway reactivity, lung inflammation
Athletes, outdoor workers, asthmatics = decreased exercise capacity, increased hospitalization
Who are affected by SULFUR DIOXIDE and what are the effects?
Healthy adults = increased respiratory infections
Indiv with chronic lung disease = increased mortality
Asthmatics = increased hospitalization, decreased lung function
Why is ground level ozone toxic?
It is largely mediated by free radicals, which injure respiratory tract epithelial cells & type 1 alveolar cells, releasing inflammatory mediators
Mild Sx = decreased lung function and chest discomfort
More dangerous for people with asthma and emphysema
Why is sulfur dioxide dangerous?
It combines with ozone, particulate matter, and water making sulfuric acid and sulfur trioxide.
Causes burning sensation in nose and throat, dyspnea, and asthma
Why is particulate matter dangerous, especially the micro sized?
It leads to pulmonary inflammation and secondary cardiovascular effects
fine/ultrafine (<10 um) most harmful b/c readily inhaled into alveoli releasing inflammatory mediators; large particles are trapped in nose
How does CO poisoning kill a patient?
Induces CNS depression; widespread ischemic changes, especially in basal ganglia and lenticular nuclei
Tissue hypoxia = lactic acidosis, cardiac and skeletal breakdown (elevated creatine kinase), neuronal findings b/c brain requires high-level O2 delivery
Why does CO travel rapidly in the body?
Hemoglobin has 200x affinity for CO than O2
Hypoxia with 20-30% sat
Unconsciousness/death with 60-70% sat (takes less than 5 min)
What is a hallmark of CO poisoning?
Generalized cherry-red color of skin and mucous membrane
What are the pollutants associated with INDOOR air pollution?
Wood smoke = polycyclic hydrocarbons are carcinogens
Bioaerosols = legionnaires dz, viral pneumonia, pet dander, fungi, mold
Radon = derived from uranium, increased risk of lung cancer
Formaldehyde = building material; carcinogen
What is sick building syndrome?
indoor air pollutants + poor ventilation
How does lead insert its effects and what are the general effects?
It is readily absorbed and binds to sulfhydryl groups in proteins and interferes with calcium metabolism
Effects = hematologic, skeletal, neurological, GI, and renal toxicity
Where is most of the absorbed lead incorporated?
Bone and developing teeth (80-85%)
Competes with calcium and has long half life
How can lead poisoning be seen in radiographs?
Lead lines
radio dense deposits in metaphyses - interferes with remodeling of cartilage
also seen in gums
Describe lead exposure in children.
Deficits in intellect, behavior problems, hyperactivity, poor organizational skills
Brain damage
sensory, motor, intellectual, and psychologic impairments, blindness, psychoses, seizures, coma
Lead exposure in mother can affect brain development in child
Describe lead exposure in adults.
CNS disturbances - peripheral neuropathies = wrist drop and foot drop
What are the skeletal deficits from lead poisoning?
inhibits healing of fractures = increasing chondrogenesis and delaying cartilage mineralization
What are the hematologic deficits from lead poisoning?
inhibition of heme synthesis (involving ferrochelatase) leading to microcytic hypochromic anemia, basophilic staining, ring sideroblasts (iron-laden mitochondria)
What are the GI deficits from lead poisoning?
Lead colic
extremely severe, poorly localized abdominal pain
What are the renal deficits from lead poisoning?
proximal tubule damage
chronic = interstitial fibrosis and possible renal failure
What are some severe neurological deficits from lead poisoning?
marked brain edema (prone to occur in children)
demyelination of cerebral and cerebellar white matter
necrosis of cortical neurons with diffuse astrocytic proliferation
What happens quickly and is characteristic of lead poisoning?
Bone and marrow changes
In microcytic hypochromic anemia, name the MCV and MCH values.
MCV (mean corpuscular volume) = <80 fL (normal is 80-85)
MCH (mean corpuscular hemoglobin) = <27 pg
How does mercury assert its effects?
Binds to sulfhydral groups, damages CNS and kidney
What are the major sources of mercury?
organic = contaminated fish
inorganic = mercury chloride from natural degassing of earth crust or industrial contamination
metallic = mercury vapors in dental amalgams
What are the effects of mercury poisoning?
Tremors, gingivitis, bizarre behavior
Minamata disease (contaminated fish in Minamata, Japan) = cerebral palsy, deafness, blindness, mental retardation, and major CNS deficits to children exposed in utero
