1.3 Environmental Factors in Disease

the six environmental diseases addressed

• enviro toxins

• tobacco

• alcohol

• non-therapeutic drugs

• therapeutic drugs

• physical agents

the types of enviro toxins:

• carbon monoxide

• lead

• mercury

what is carbon monoxide?

colorless, odorless, tasteless, non-irritating gas

• chronic poisoning may develop working in confined enviro

• most common direct chemical cause of death

how does carbon monoxide work?

• hemoglobin replaced by carboxyhemoglobin which limits capacity to carry oxygen

• acute: cheery/vibrant red skin and oral mucosa

• result: irreversible impairment of memory, vision, hearing, speech

lead as enviro toxin

• pipes, gas, paint

• absorption: 80-85% uptake teeth, bone 5-10% in blood, rest in soft tissues

• Flint: switch to Detroit river as water source but lead pipes

  • more than 25% of homes greater than acceptable limit of 15 ppb

  • some house up to 13, 000 ppb

how does lead toxicity affect people?

children:

• generally irreversible

• low IQ

• hyperactive

• poor organizational skilla

adult: peripheral neuropathies

what is Burton’s line?

along gingival margin, result of heavy metal toxicity: lead

on hard tissue of teeth and soft tissue of gingiva

mercury as enviro toxin

mercuric chloride

• source: seafood, mad hatter textile industry

• result: acute GI ulcers ad severe renal damage

mercury toxicity can cause:

• tongue tremor

• gingivitis

• bruxism

• excessive salivation

• trichotillomania: pull one’s hair

best recognized traditional risk factor for oral/oropharyngeal squamous cell carcinoma

tobacco (and heavy alcohol consumption)

other risk factors: HPV, h/o cancer, immunosuporession

clinical presentations of oral and oropharyngeal cancer

• leukoplakia: white

• erythroplakia: red

• non-healing ulcer

• exophytic mass

high risk location of oral and oropharyngeal cancer

• ventro-lateral tongue

• floor of mouth

• tonsillar pillars

oral and oropharyngeal cancer 5-year survival rate:

67%

Dna damage to epithelial cells of vaper vs non-vapers

2.6 times the damage

one drink is how many g of pure alcohol

• 1.5 oz distilled liquor

• 5 oz wine

• 12 oz beer

moderate vs heavy drinker

	men	women
moderate	2/day	1/day
heavy	15/wk or 4/day	8/wk or 3/day

three drugs of abuse

• cocaine

• heroin

• marijuana

• 1.5 mil users, 15-20% crack

• smoked (w tobacco), ingested, injected, snorted

• among most addictive of all drugs ‘no physical dependence

• cardiovascular, CNS, teratogenic effects

• vasoconstrictive, ischemia, palatal perforations

cocaine

• from poppy plant

• sequelae: a condition which is the consequence of a previous disease or injury

  • sudden death

  • pulmonary disease

  • infections

  • skin lesion

  • renal disease

heroin

• increases heart rate and bp

• 3-fold increase in tar inhaled and retained in lungs compared to tobacco

• in MA: indiv 1oz on person and 10oz in home but use prohibited in public

marijuana

therapeutic drugs addressed

aspirin, acetaminophen, hormonal replacement therapy, oral contraceptives, immunosuppressive, cancer chemotherapy

• chronic toxicity → gastroduodenal bleeding

• reye syndrome: encephalopathy following acute, febrile, viral illness in child

aspirin

• large dose lead to hepatic necrosis

• toxicity starts with nausea, vomiting, diarrhea

• in suicide attempts

acteaminophen

Aspirin and acetaminophen are both

nonsteroidal anti-inflammatory drugs (NSAIDs) that inhibit cyclooxygenase (COX) enzymes in stomach lining = irritation

hormonal replacement therapy adverse effects

• thrombosis: blood clots

• breast cancer

• endometrial carcinoma

oral contraceptives adverse effects

• thrombosis: blood clots

• increase cervical cancer risk

• no increase risk of breast cancer

• protective against endometrial cancer

immunosuppressive adverse effects

opportunistic infections

cancer chemotherapy adverse effects

• alopecia

• GI erosion/ulceration

• bone marrow failure

• acute leukemia

• other malignancies

two types of injury by physical agents

mechanical and radiation injury

physical injury type causes of death:

• hemorrhage into body cavities

• fat embolism from bone fractures

• ruptured viscera

• secondary infection

• renal failure

mechanical: abrasions, contusions, lacerations incised wounds, puncture wounds

effects of (BLANK) trauma:

• chronic low-grade trauma: prolif of tissue by stimulating fibroblasts and collagen

  • ex: poor fitting dentures can cause damage in vestibule

what type of physical injury leads to

• DNA damage and carcinogenesis

• damage to organ systems

• fibrosis

(Ionizing) radiation: electron release cascade

(vs non-ionizing moves but does not displace electrons)

radiosensitivity of

• bone

• teeth

• cartilage

• muscle

• CNS

• kidney

• liver

• most endocrine glands

low sensitivity

radiosensitivity of

• lymphoid

• hematopoetic

• germ

• GI mucosa

• rapidly dividing tumor cells

high sensitivity

radiosensitivity of

• fibroblasts

• endothelial cells

• elastic tissue

• salivary glands

• eye

intermediate sensitivity

how does ionizing radiation injury work?

50 Gy (5,000) to any one body region: no severe or lethal consequences, but possible minor changes

what amount of ionizing radiation injury is deadly?

• 3 Gy to whole body 20-50% death

• 10 Gy to whole body 100% death

ionizing radiation sequelae

• neoplasia: leukemias, cancers of bone, skin, thyroid, lung, breast

• severe CNS injury

• mucosal ulcers

• acute bone marrow failure