Flashcards in Chapter 7 - Environmental Pathology Deck (125):
What is the leading cause of premature death in developed countries?
Tobacco use leading cause of premature death in developed countries
What is the most important preventable cause of death in the United States?
Smoking: most important preventable cause of death in United States
What is nicotine?
Nicotine: addictive component in tobacco
Besides addiction, nicotine patch can be used to treat what?
Nicotine patch used to Rx ulcerative colitis
What is cotinine?
Cotinine: nicotine metabolite; used for screening
What does tar in cigarette smoke contain?
Tar contains carcinogenic agents
What are the carcinogens in cigarette smoke?
Carcinogens: polycyclic hydrocarbons, phenol, nitrosamine
What can smokeless tobacco cause?
Smokeless tobacco: addictive; ↑risk for oral squamous cancer
What does passive smoke increase the risk of in children?
Passive smoke: ↑risk of respiratory/middle ear infections in children
What does secondhand smoke exacerbate in children?
Smoking exacerbates asthma
What does passive smoke increase the risk for in adults?
Passive smoke: risk for lung cancer; CAD
What are the beneficial effects of smoking cessation?
Live longer; ↓risk for heart disease, lung cancer, stroke
What is the most common recreational drug taken in the U.S.?
Alcohol MC recreational drug
Where is alcohol metabolized and reabsorbed?
Stomach/liver metabolize alcohol; stomach/small bowel reabsorb alcohol
Why are women at risk for acute/chronic alcohol complications?
Women at risk for acute/chronic alcohol complications; ↓alcohol dehydrogenase
What are the enzymes that metabolize alcohol?
Enzymes metabolizing alcohol: alcohol dehydrogenase, CYP2E1, catalase
What is the rate-limiting enzyme in alcohol metabolism?
ADH: rate-limiting enzyme in alcohol metabolism
What is key to lab abnormalities in alcohol metabolism?
↑NADH key to lab abnormalities
How does role of increased NADH in alcohol metabolism?
↑NADH: ↑synthesis lactic/β-OHB acids; ↑liver TG synthesis
Acetyl CoA is used to synthesize what?
Acetyl CoA used to synthesize fatty acids/ketoacids
Describe why there is increased risk for fasting hypoglycemia in alcohol metabolism.
NADH enhances pyruvate conversion to lactate → ↓pyruvate → fasting hypoglycemia
What anions are present in the increased anion gap metabolic acidosis of alcohol abuse?
↑Anion gap metabolic acidosis: lactic acid, β-OHB acid
Which ketone is not detected with standard urine/blood tests for ketone bodies?
β-OHB not detected with standard urine/blood tests for ketone bodies
Besides fasting hypoglycemia and acidosis, what are the other laboratory findings in alcohol abuse/alcoholic liver disease?
Lactic acid/β-OHB → hyperuricemia (potential for gout); hypertriglyceridemia
Alcohol liver disease: AST > ALT; ↑GGT
What is the most common systemic complication of IVDU?
Hepatitis C: MC systemic complication of IVDU
What are the effects of acetaminophen overdose?
Acetaminophen: chemical hepatitis; renal papillary necrosis
What are the general symptoms of aspirin overdose?
Aspirin: tinnitus, vertigo, tachypnea
What is the initial acid-base disorder in aspirin overdose?
Initial respiratory alkalosis
What is the mixed acid-base disorder in aspirin overdose in adults?
Mixed primary respiratory alkalosis and metabolic acidosis (adults)
What is there danger of in salicylate poisoning?
Salicylate poisoning: danger of hyperthermia
Both acetaminophen and aspirin toxicity may cause what?
Both acetaminophen and aspirin toxicity may cause fulminant hepatitis
Unopposed estrogen increases the risk for what?
Unopposed estrogen: adenocarcinoma endometrium/breast
Risk venous thromboembolism; intrahepatic cholestasis
Risk myocardial infarction/stroke
OCPs increase the risk for what?
OCP: risk breast adenocarcinoma, cervical SCC
Risk folic acid deficiency (macrocytic anemia)
OCP MCC hypertension in young women → ↑angiotensinogen → ↑ATII
Risk hepatic adenoma causing intraperitoneal hemorrhage
Risk of intrahepatic cholestasis/cholesterol gallstones
What is the most common cause of death due to a venomous bite?
Bee/wasp/hornet sting: MCC death due to a venomous bite
What is a contusion?
Contusion: blunt force injury to blood vessels with blood leaking into tissue
What is an abrasion?
Abrasion: superficial excoriation of epidermis
What is a laceration?
Laceration: jagged tear with intact bridging vessels/nerves/connective tissue
What is an incision?
Incision: wound with sharp margins; severed blood vessels
Describe contact gunshot wounds.
Contact wound: stellate-shaped; fouling (soot + gunpowder)
Describe an intermediate-range gunshot wound.
Intermediate-range wound: powder tattooing
Describe a long-range gunshot wound.
Long-range wound: no powder tattooing
Describe exit gunshot wounds.
Exit wounds: larger than entrance wound
What is the most common cause of death ages 1 to 44 years?
MVAs MCC death ages 1 to 44 years
What accounts for more than 50% of deaths from child abuse?
Shaken baby syndrome: >50% deaths from child abuse
What is the key finding in shaken baby syndrome?
Key finding: retinal hemorrhages
What is the most common cause of burns?
MCC burns is fire
What is the most common site for burns?
MC site for burn is upper extremities
What is the common denominator in all burns?
Common denominator in burns is protein denaturation
What does the center of a burn have?
Center of burn has irreversible coagulation necrosis
Describe the zone of ischemia of a burn.
Zone of ischemia has reduction in dermal microcirculation
Describe the zone of hyperemia in a burn.
Zone of hyperemia due to immediate and transient increase in perfusion
What does the depth of a burn determine?
Depth of burn determines potential for skin regeneration
What are the sources for skin regeneration?
Sources for skin regeneration: basal layer of cells at margins; dermal skin appendages
What is a first degree burn?
1st degree burn: limited to epidermis
What is a superficial second-degree burn?
2nd degree superficial: extends into papillary dermis; partial-thickness burn
What is a deep second-degree burn?
2nd degree deep: extends into reticular dermis; partial-thickness burn
What is a third-degree burn?
3rd degree burn: extends through epidermis/dermis; full-thickness
What common occurs following a third-degree burn? What can potentially develop?
SCC risk in keloids
What is a fourth-degree burn?
4th degree burn: extends thru skin, subcutaneous fat, muscle/bone
What is a possible effect of losing plasma from the burn surface?
Hypovolemic shock from loss of plasma; pitting edema
What is the most common cause of infection of a burn wound?
P. aeruginosa MCC infection of burn wound
What may develop in the small intestine as a complication of a severe burn?
Curling ulcers of proximal duodenum
What is hypermetabolic syndrome?
Hypermetabolic syndrome: heat loss from damaged skin surface → ↑BMR
Smoke inhalation may result in what type of poisoning?
Smoke inhalation: CO/CN poisoning
What is heat edema?
Heat edema: mild swelling feet, ankles, hands
What is heat edema due to?
Cutaneous vasodilation with gravitational pooling
Who is affected by heat edema?
Elderly in tropical/semitropical area; healthy traveler coming from cold to hot area
What are heat cramps?
Heat cramps: painful, spasmodic muscle contractions postexercise
Describe the electrolyte derangement in heat cramps.
Deficiency Na+, Cl−, and fluids in muscle
What is heat exhaustion?
Heat exhaustion: volume depletion under conditions of heat stress
What are the clinical findings in heat exhaustion?
Heat exhaustion: <104° F); profuse sweating/no mental status changes
Describe the laboratory findings in heat exhaustion.
Hemoconcentration, variable serum Na+
What are the predisposing factors for heatstroke?
CHS: high ambient temperature; poor, elderly without air-conditioning
CHS: chronic disorders (psychiatric, alcoholism) requiring medication
What are the clinical findings in classic heatstroke?
Core body temp >40° C (104° F); skin hot/dry; mental status abnormal; CNS dysfunction
What are the laboratory findings in classic heatstroke?
Mild respiratory alkalosis; mild ↑serum CK
What are the predisposing factors for exertional heatstroke?
EHS: athletes/military recruits; endogenous heat production overrides cooling mechanisms
What are the clinical findings in exertional heatstroke?
EHS: Core body temp >40° C (104° F); profuse sweating; severe CNS dysfunction
What are the lab findings in exertional heatstroke?
Lactic acidosis, rhabdomyolysis, ARF, DIC, liver damage, hypocalcemia
What is the most common freezing injury to tissue?
Frostbite MC freezing injury to tissue
What is trench foot/immersion foot?
Trench foot/immersion foot: nonfreezing injury; exposure to wet cold
What is chilblain?
Chilblain: nonfreezing injury; exposure to dry cold
What is the pathogenesis of frostbite?
Frostbite: tissue exposed to temperature <0° C
Frostbite: ice crystallization; stasis of blood flow
What occurs during the prefreeze phase of frostbite?
Prefreeze: endothelial plasma leakage; vasoconstriction; ↑plasma viscosity
What occurs during the freeze-thaw phase of frostbite?
Freeze-thaw phase: extracellular ice crystallization; intracellular volume depletion → death
What occurs during the postthaw phase of frostbite?
Postthaw: microvascular collapse → necrosis
Describe the epidemiology of electrical injury.
Most injuries in children or work-related
What is the main determinant of tissue injury in electrical injury?
Current main determinant of tissue injury
What is Ohm's law?
Ohm’s law: Current (I) = Voltage (V)/Resistance (R)
What change in resistance or voltage results in a decrease in current?
↑Resistance (R) or ↓Voltage (V) = ↓Current (I)
What change in resistance or voltage results in an increase in current?
↓Resistance (R) or ↑Voltage (V) = ↑Current (I)
How does AC exposure compare to DC exposure at the same voltage?
AC 3× more dangerous that DC at same voltage
How do muscle contractions differ during AC and DC exposure?
AC induces tetanic contractions (hold on); DC induces single muscle spasm (throws away)
How does wet skin affect resistance and current?
Wet skin ↓R causing ↑I
How does dry skin affect resistance and current?
Dry skin ↑R causing ↓I
What is the most common cause of death in an electrical injury?
Cardiorespiratory arrest MCC death electrical injury
What is the most common cause of death from lightening injury?
Cardiorespiratory arrest MCC death from lightening injury
Who is most at risk for drowning?
Children 1 to 4 and 10 to 14 years old most at risk for drowning
Drowning: death by suffocation from immersion in a liquid
What is wet drowning?
Wet drowning: aspiration of water; MC type of drowning
What is immersion syndrome?
Immersion syndrome: sudden death from submersion in cold water; vagally mediated cardiac arrest
What is dry drowning?
Dry drowning: asphyxia from laryngospasm without aspiration
Describe two features of the diving reflex.
Diving reflex protective; shunts blood to vital areas
Describe the cause of death in drowning.
Death in drowning: laryngospasm/closed glottis; hypoxemia with respiratory/metabolic acidosis
How are O2 concentration and atmospheric pressure affected at high altitude?
High altitude: O2 concentration 21%, ↓atmospheric pressure
Describe the effect of hypoxemia at high altitude.
Hypoxemia stimulates peripheral chemoreceptors → respiratory alkalosis
Describe the effect of respiratory alkalosis on OBC.
Respiratory alkalosis → activates PFK → ↑2,3-BPG → right-shifted OBC
Acute mountain sickness occurs at what elevation?
AMS occurs at elevations >8000 feet (2440 m)
What are the clinical findings in acute mountain sickness?
Headache, fatigue, dizziness, anorexia, nauseous, insomnia
Describe the pulmonary edema in high altitude pulmonary edema.
HAPE: noncardiogenic pulmonary edema
What are the clinical findings in high altitude cerebral edema?
HACE: ataxia, stupor, coma
Give two examples of ionizing radiation.
Ionizing radiation: x-rays, γ-rays
Describe the pathophysiology of ionizing radiation.
Damage to DNA by hydroxyl free radicals
Which tissue is most sensitive to ionizing radiation?
Lymphoid tissue most sensitive to ionizing radiation
Which tissue is least sensitive to ionizing radiation?
Bone least sensitive to ionizing radiation
What is the first hematologic sign of total body radiation?
Total body radiation: lymphopenia first hematologic sign
What are the vascular effects of radiation?
Vascular system: thrombosis/fibrosis; ischemia
What are the acute integumentary effects of radiation?
Acute—erythema, edema, blisters
What are the chronic integumentary effects of radiation?
Chronic—radiodermatitis; danger of SCC
What are the acute and chronic GI effects of radiation?
Acute—diarrhea; chronic—bowel adhesions
What is the most common cancer caused by radiation?
Acute leukemia MC cancer caused by radiation
What other cancers are caused by radiation besides acute leukemia?
Other radiation cancers: papillary carcinoma of thyroid, osteogenic sarcoma
Describe the pathogenesis of injury with UVB light.
UVB: ↑pyrimidine dimers distort DNA helix
UVB: inactivates p53 suppressor gene; activates RAS proto-oncogene
What are the general effects of UVB light injury?
Sunburn, actinic (solar) keratosis (danger SCC), corneal burns from skiing
What are the cancers associated with UVB light injury?
UVB cancers: BCC (MC), SCC, melanoma