Environmental Injury Flashcards
1
Q
Carcinogenesis Process
A
- 1- Initiation - exposure to certain chem (initiator) —> genetic mutation
- Must be permanent change for cancer to develop AKA the cell w/ mutation must proliferate
- Alternatives- mutated cell dies or DNA is repaired
- Direct initiators (no modification needed) v indirect initiators (require modification)
- 2- Promotion
- Promoters lead to cell proliferation AKA propagate the mutation by inc cell division
2
Q
Lead
A
- Source - house plants, gasoline, pain, batteries, pigment, car radiators, old houses
- Children more susceptible to toxicity b/c absorb 50% of what’s ingested (adults only 15%) - should be 2- 5 in old house- 45 needs intervention
- Symptoms
- First - drop in IQ, behavioral probs/hyperactivity, poor organization
- Later - incorporated into bone (lead lines - dense in epiphyses) and teeth (lines in gums); abdominal pain, renal tubulointerstitial disease
- Mechanism
- Binds sulfhydryl groups in proteins - interferes w/ Ca++ binding so incorporated into bone and teeth where it competes w/ Ca++
- Inhibits neurotransmitters - CNS probs
- Histo- RBCs w/ large/extended white area in center (replaces iron in blood)
3
Q
Mercury
A
- Source - contaminated fish (esp high up food chain - tuna), dental amalgams, diuretics, cosmetics, etc
- Mechanism -
- Binds sulfhydryl groups of certain proteins (esp in CNS and kidneys)
- Help w/ glutathione to donate sulfhydryl groups
4
Q
Arsenic
A
- Source - herbicides, soil, water, wood preservers, mines, smelting industries
- Mechanism -
- Interferes w/ oxid phosphorylation (replace phosphates of ATP)
- Symptoms -
- First - sensorimotor (numbness, pain)
- Later- hyper pigmentation and hyperkeratosis; inc cancer risk in lung, bladder, skin (cancer due to defects in nucleotide excision repair)
5
Q
Cadmium
A
- Preferentially toxic to kidneys and lungs
- Source - occupational exposure to pollutant in mining, electroplating, production of nickel-cadnium batteries
- Mechanism - taken up into cells by zinc transporters; then inc production of ROS?
- Symptoms
- Obstructive lung disease
- Renal tubular fail
- Osteoporosis + osteomalacia
- Elevated risk of lung cancer
- Skeletal abnormalities if Ca++ loss
6
Q
Silicates
A
- Source - occupational; mining, sandblasting, stone carving, etc
- Mechanism -
- Inhale —> phag by macrophages —> activate inflammatory cascade —> release IL-1 and IL-8
- Gross exam
- Blackened nodules in upper lung —> hard collagenous scars w/ central softening
- Sheets of calcification in lymph nodes
- Histo exam
- Central area of whirled collagen fibers (onion layers) w/ peripheral zone of dust-laden macrophages
- Symptoms -
- Lung disease
- Inc susceptibility of Tb
- Inc risk of lung cancer
- Predisposition to rheumatoid arthritis
7
Q
Thermal Burns
A
- Dep on depth of burn and percentage of body surface involved; if there are internal injuries from inhalation AND promptness of therapy
- Serous inflammation v exudate dep on extent of damage
- Complications
- Shock
- Sepsis
- Respiratory insufficiency (due to injury to airway and lungs)
- Microscopic findings - coagulative necrosis and exudation
- Resolution/healing - hypertrophic scars
8
Q
Hyperthermia
A
- Heat cramps (loss of electrolytes)
- 2- Heat exhaustion (hypovolemia due to dehydration but heart cannot comp)
- 3- Heat stroke (enzymes stop working)
- Risk Factors
- older adults, high physical stress, cardiovascular disease
- Mechanism
- Vasodilation
- Hyperkalemia —> cardiac arrhythmia
- Enzymes stop working —> inc Ca++ from SER —> muscles in persistent contraction —> muscle necrosis (problems w/ ryanodine receptors); produces more heat
**Malignant hyperthermia mimics this b/c inherited mutation in RYR1
9
Q
Hypothermia
A
- Lowering of body temp is hastened by inc humidity, wet clothes, alcohol consumption
- Loss of consciousness @ 90F, then bradycardia and a fib
