Lecture 9 - Environmental Diseases Flashcards
what do ‘environmental diseases’ refer to?
it refers to injuries or disorders that are caused by chemical or physical agents
- a related field, occupational medicine, focuses on injuries that occur in the workplace from these same factors
- In US work related injuries occur 2X more frequently than home injuries at an annual cost exceeding 25 billion
Us agencies involved in regulating environmental hazards include:
- environmental protection agency
- food and drug administration
- occupational and safety health administration
- consumer products safety comminssion
what are the categories of environmental diseases
- air pollution - indoor/ outdoor pollution
- industrial exposures - coal, asbestos, other metals
- tobacco smoke - major public health problem
- chemical agents - mechanical trauma, thermal injury
- electrical injury
- radiation injury
- nutritional diseases
how do injuries occur from chemical agents?
inhalation, ingestion, injection or absorption through the skin
- 2 million exposures in US evert year
- 90% unintentional
oral intake accounts for what percent of exposures?
73% of exposures
children less than 6 years account for what percent of exposures?
61% of exposures
adverse drugs account for what percent of exposures?
2% of exposures
what are the most frequent chemical agents that cause injury?
common household items: cleaning agents, analgesics, cosmetics, plants or cold preparations
what does CLADME stand for?
They are factors that affect chemical injuries
Concentration Liberation Absorption Distribution Metabolism Excretion
adverse drug rxs are common affecting 7-8% of hospitalized persons and 10% of these are fatal. Anaphylaxis can occur with any medication, but it is more often associated with which class of drug?
antibiotics (pennicillin is the classic)
the more potent the drug - the more likely it is..
to cause an adverse rxn
anti-cancer drugs are the best examples
aspirin (ASA) overdose can be acciental (young kids) or intentional (adults). what gm amount is fatal in kids and what in adults?
kids - 2-4 gms
adults - 10-30 gm
with aspirin the major acute injury is….
metabolic one - first there is respiratory alkalosis followed by metabolic acidosis
chronic ingestion (3 gm or more per day) is associated with what side effects?
headaches dizziness ringing in the ears (tinnitus) drowsiness mental status changes gastritis GI bleeding nausea vommiting *it may even progress into seizures and come
what g amount causes overdose in acetaminophen
overdose occurs after large ingestion (15-20 g)
what is the toxicity and side effects associated with acetaminophen?
toxicity: liver damage (over several hours to days)
early symptoms: nausea, vomiting, diarrhea - then following by jaundice and shock as the liver failure progresses
*There might also be heart and kidney damage as well
exogenous estrogens and oral contraceptives if pts are receiving long term hormone replacement therapy are at an increased risk for:
breast cancer, strokes and blood clots
- The benefits of SHORT term therapy ( s/a alleviation of severe peri-menopausal symptoms or prevention of osteoporosis if no other modality is effective) may outweigh these risks
what are some risks and some benefits of oral contraceptives?
risks - blood clots, hypertension, hepatic adenoma, cholecystitis, slightly increased risk in breast cancer)
benefits - contraception, protective effect for endometrial and ovarian cancers
what are some examples of nontherapeutic agents?
environmental exposures: lead, carbon monoxide, cleaning agents, cyanide, ethylene glycol, organophosphates (pesticides), mercury, plants (mushrooms) petroleum products
also_ agents that may be ingested for mind/ mood altering experiences
where is lead found in the environment and which type have occupations have an increased risk?
environment - urban air, soil, water, food, house dust, gasoline (historical), batteries, old paints
occupations - foundry workers and mining
lead has high affinity for enzymes involved in the synthesis of hemoglobin which blocks or hinders the incorporation of….
iron into the molecule
which type of anemia can patients develop from lead exposure?
microcytic hypochromic anemia
ughhhhh more anemiaaaa
which part of the body is the majority (80-85%) of absorbed lead taken up?
bones and teeth
- lead competes with calcium and interferes with the normal remodeling process
- bone becomes hyperdense with changes (lead lines) visible on x-rays
lead deposits int he gums causes…
hyperpigmentation
lead toxicity in the CNS is more likely to occur in which age group?
kids
which type or neurologic disorders may be seen with lead exposures?
mind deficits to sensory, motor, cognitive and psychologic
*reduced IQ’s and disabilities may result
in adults, lead toxicity may lead to…
peripheral neuropathies (wristdrop and footdrop)
lead toxicity in the GU tract is characterized by what?
severe, poorly localized, “colicky pain”
*lead is also toxic in renal tubules which may ead to intersitial fibrosis and renal failure
the maximum allowable blood level was reduced from ___ to ___ ug/dL in 2012.
What is the treatment for lead posioning
reduced from 10 to 5 ug/dL
treatment is chelation therapy (startign at 45 ug/dL) and supportive measures
what are the general classes of drugs of abuse? (7 of them)
- sedative-hypnotics - alcohol, barbiturates, benzodiazepines
- CNS stimulants - cocaine, amphetamines,weight loss products
- opioids - heroine, morphine, methadone, codeine
- cannabinoids - marijuana
- hallucinogens - LSD, mescaline, phencyclidine (PCP), ketamine
- inhalants - glues, toluene, paint thinner, gasoline, amyl nitrate, nitrous oxide
- nonprescription drugs - atropine, scopolamine, antihistamines, weak analgesics
what are some examples of “club drugs”
methamphetamines (MDMA, ecstasy)
hallucinogens (LSD, ketamine and CNS depressants and benzodiazepines)
what is a side of effect of MDMA that we will directly see as dentists
bruxism - clenching of the teeth
*they use pacifiers to avoid this while at the same time storing another “hit”
in terms of mechanical injury, what is the definition of abrasion?
a wound produced by scraping or rubbing leading to removal of a superficial layer of skin
in terms of mechanical injury what is the definition of contusion?
bruise, a wound caused by a blunt object, doesnt break the skin but may lead to damage of blood vessels and extravasation of blood in tissues