Ch 9: Environmental and Nutritional Diseases Flashcards

1
Q

What is the “Global Disease Burden”?

A

It estimates the burden imposed by environmental dz

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2
Q

What is “Disability adjusted life year” (DALY)?

A

Sum of years of life LOST due to premature mortality and disability in a population.

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3
Q

Describe the prevalence of HIV/AIDS between 1990s and now.

A

There have been large increases in mortality due to HIV/AIDS since the 1990s.

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4
Q

What is the single leading global cause of health loss (morbidity + premature death)?

A

Undernutrition

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5
Q

What is the leading cause of death in developed countries?

A

Ischemic heart and cerebral vascular disease

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6
Q

How prevalent is infectious disease in developing countries? Name the most common ones.

A

5/10 leading causes of death are infectious diseases.

Respiratory infections
HIV/AIDS
Diarrheal diseases 
TB 
Malaria
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7
Q

In the postnatal period, ~50% of all deaths in kids younger than 5 are attributed to 3 conditions. What are they?

A

pneumonia
diarrheal dz
malaria

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8
Q

Describe some changing trends in GBD.

A

Increasing Cardiovascular disease, cancer, HIV

Decreasing diarrheal dz and neonatal conditions

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9
Q

Name the categories of emerging infectious dz and give examples.

A

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)

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10
Q

What is poised to become the global leading cause of environmental disease?

A

Climate change

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11
Q

Climate change has serious negative impact on human health by increasing incidence of dz. Name a couple and why they are becoming more prevalent.

A

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

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12
Q

Define toxicology.

A

distribution, effects, and mechanisms of action of toxic agents

physical agents = radiation, heat

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13
Q

What is poison dependent on?

A

dosage!

all substances are poisons - the right dosage differentiates poison from remedy

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14
Q

Define Xenobiotics.

A

exogenous chemicals in environment that may be absorbed into body

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15
Q

What is characteristic of xenobiotics that helps them be absorbed easily?

A

They are lipophilic - facilitates transportation and penetration through basement membrane

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16
Q

What 2 things happen to xenobiotics in the body?

A

Metabolized to inactive water-soluble product = detoxification

Activated to form toxic metabolites

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17
Q

What enzyme family makes xenobiotics toxic? Can they also detoxify? If so, how?

A

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

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18
Q

Where is the CYP450 enzyme system found?

A

Primarily ER of liver

but also sin, lungs, GI

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19
Q

What is the more common action of CYP450?

A

Detoxification

Less common = converting xenobiotics into active compounds

20
Q

Will both mechanisms of CYP450 cause cell injury? Explain.

A

Yes, because both produce ROS as a byproduct

21
Q

What does CYP450 metabolize carbon tetrachloride into? What other compounds does it metabolize?

A

It converts the dry cleaning agent into a toxic trichlozomethyl free radical

Also metabolizes acetaminophen, barbiturates, warfarin, alcohol, and anticonvulsants.

22
Q

What are the pollutants associated with OUTDOOR air pollution?

A
Sulfur dioxide
Carbon monoxide 
Ozone
Nitrogen dioxide 
Lead
Particulate matter (soot)
23
Q

Who are affected by OZONE and what are the effects?

A

Healthy adults and children = decreased lung function, increased airway reactivity, lung inflammation

Athletes, outdoor workers, asthmatics = decreased exercise capacity, increased hospitalization

24
Q

Who are affected by SULFUR DIOXIDE and what are the effects?

A

Healthy adults = increased respiratory infections

Indiv with chronic lung disease = increased mortality

Asthmatics = increased hospitalization, decreased lung function

25
Q

Why is ground level ozone toxic?

A

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

26
Q

Why is sulfur dioxide dangerous?

A

It combines with ozone, particulate matter, and water making sulfuric acid and sulfur trioxide.

Causes burning sensation in nose and throat, dyspnea, and asthma

27
Q

Why is particulate matter dangerous, especially the micro sized?

A

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

28
Q

How does CO poisoning kill a patient?

A

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

29
Q

Why does CO travel rapidly in the body?

A

Hemoglobin has 200x affinity for CO than O2

Hypoxia with 20-30% sat
Unconsciousness/death with 60-70% sat (takes less than 5 min)

30
Q

What is a hallmark of CO poisoning?

A

Generalized cherry-red color of skin and mucous membrane

31
Q

What are the pollutants associated with INDOOR air pollution?

A

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

32
Q

What is sick building syndrome?

A

indoor air pollutants + poor ventilation

33
Q

How does lead insert its effects and what are the general effects?

A

It is readily absorbed and binds to sulfhydryl groups in proteins and interferes with calcium metabolism

Effects = hematologic, skeletal, neurological, GI, and renal toxicity

34
Q

Where is most of the absorbed lead incorporated?

A

Bone and developing teeth (80-85%)

Competes with calcium and has long half life

35
Q

How can lead poisoning be seen in radiographs?

A

Lead lines

radio dense deposits in metaphyses - interferes with remodeling of cartilage

also seen in gums

36
Q

Describe lead exposure in children.

A

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

37
Q

Describe lead exposure in adults.

A

CNS disturbances - peripheral neuropathies = wrist drop and foot drop

38
Q

What are the skeletal deficits from lead poisoning?

A

inhibits healing of fractures = increasing chondrogenesis and delaying cartilage mineralization

39
Q

What are the hematologic deficits from lead poisoning?

A

inhibition of heme synthesis (involving ferrochelatase) leading to microcytic hypochromic anemia, basophilic staining, ring sideroblasts (iron-laden mitochondria)

40
Q

What are the GI deficits from lead poisoning?

A

Lead colic

extremely severe, poorly localized abdominal pain

41
Q

What are the renal deficits from lead poisoning?

A

proximal tubule damage

chronic = interstitial fibrosis and possible renal failure

42
Q

What are some severe neurological deficits from lead poisoning?

A

marked brain edema (prone to occur in children)

demyelination of cerebral and cerebellar white matter

necrosis of cortical neurons with diffuse astrocytic proliferation

43
Q

What happens quickly and is characteristic of lead poisoning?

A

Bone and marrow changes

44
Q

In microcytic hypochromic anemia, name the MCV and MCH values.

A

MCV (mean corpuscular volume) = <80 fL (normal is 80-85)

MCH (mean corpuscular hemoglobin) = <27 pg

45
Q

How does mercury assert its effects?

A

Binds to sulfhydral groups, damages CNS and kidney

46
Q

What are the major sources of mercury?

A

organic = contaminated fish

inorganic = mercury chloride from natural degassing of earth crust or industrial contamination

metallic = mercury vapors in dental amalgams

47
Q

What are the effects of mercury poisoning?

A

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