Pathology
Pathology/A/46
Pathology of smoking-related disorders
乳幼児突然死症候群（SIDS）／早産（未熟児）
- タグ
- High-yield / ポイントMechanism / 機序
1. Tobacco: scope & constituents
Tobacco is the most common exogenous cause of human cancer (~90% of lung cancer). Active substances are absorbed via the alveoli (smoking) or oral mucosa (chewing/snus).
| Constituent | Effect |
|---|---|
| Nicotine | Addiction; ↑ HR/BP, cutaneous vasoconstriction; ↑ platelet stickiness |
| Formaldehyde, NOx, hydrogen cyanide | Ciliotoxic, mucosal irritation |
| Carbon monoxide | Impaired O₂ transport (carboxyhemoglobin) |
| Tar, PAH, benzopyrene, nitrosamine, arsenic, chromium | Carcinogenesis |
| Phenol | Tumor promotion |
2. Smoking-related diseases
- Lungs (main target):
- Direct irritation of tracheobronchial mucosa → inflammation + ↑ mucus → chronic bronchitis.
- Leukocyte recruitment → ↑ elastase → alveolar destruction → emphysema.
- Lung cancer — dose-related to exposure intensity.
- Also goblet-cell metaplasia, mucous plugging, smooth-muscle hypertrophy, bronchial wall fibrosis.
- Cardiovascular — atherosclerosis & myocardial infarction: ↑ platelet aggregation, ↓ myocardial O₂ supply (CO hypoxia) + ↑ demand, ↓ VF threshold; multiplicative risk with hypertension + hypercholesterolemia.
- Other cancers — oral cavity, esophagus, pancreas, bladder.
- Maternal smoking — ↑ spontaneous abortion, premature birth, intrauterine growth retardation.
- Secondhand smoke — lung cancer, coronary atherosclerosis, fatal MI, respiratory illness, asthma.
3. Air pollution (related environmental disease)
- Outdoor (smog = gaseous + particulate): CO (colorless/odorless), ozone (free radicals injure airways), NO₂ (↑ airway reactivity), SO₂/acid aerosols (impaired mucociliary clearance), particulate matter (main driver of morbidity/mortality), lead.
- Indoor: tobacco smoke, CO, NO₂, wood smoke (carcinogens), bioaerosols (Legionella, viruses, dust-mite/mold allergens).
💡 High-yield: Smoking = #1 exogenous carcinogen (90% of lung cancer). Lung: chronic bronchitis (irritation/mucus), emphysema (↑ elastase), lung cancer. CV: atherosclerosis/MI (CO + platelets). Also oral/esophageal/pancreatic/bladder cancer; maternal smoking → IUGR/prematurity. Particulate matter is the deadliest air pollutant.