Page 228 - Concise Pathology for Exam Preparation ( PDFDrive )

9 Environmental and Nutritional Pathology 213

Other Effects of Smoking
• Ischaemic heart disease (due to accelerated atherosclerosis, increased platelet aggrega-
tion and impaired lung function, which causes reduced myocardial oxygen supply)
• Peptic ulcer disease
• Cerebrovascular accident (CVA)
• Chronic respiratory disease (exacerbates bronchitis, asthma and pneumoconiosis)
• Increased incidence of low birthweight, prematurity and spontaneous abortion as a
consequence of maternal smoking

Air Pollution
1. Outdoor: problem of industrialized countries. Following are the major sources:
(a) Combustion of fossil fuels from vehicles, power plants and factories
(b) Photochemical reactions (oxides of nitrogen and hydrocarbons interact to produce
‘ozone’ which causes decreased lung function, increased airway/lung inflammation
and decreased exercise capacity)
(c) Power plant emissions (sulphur dioxide which causes decreased lung function)
(d) Waste from incinerators/industry/smelters (acid aerosols, organic compounds and
particles, which damage the mucociliary apparatus, decrease lung function and
increase respiratory infections)
(e) Automotive engines, industries using fossil fuels and home heating with oil and
cigarette smoke (carbon monoxide or CO which is a nonirritant, colourless and
odourless gas produced by imperfect combustion of carbonaceous material)
2. Indoor: caused by
(a) CO: Can cause acute poisoning
(b) NO 2 : Predisposes to respiratory infections
(c) Wood smoke: Contains oxides of nitrogen and carbon particulates which are
irritants and predispose to lung infections
(d) Formaldehyde: Causes eye and nose irritation and asthma
(e) Radon: Radioactive gas derived from uranium widely present in soil and homes;
can cause lung cancer in uranium miners
(f) Asbestos fibres: Occupational exposure can produce lung cancer and mesotheliomas
(g) Mineral fibres: Used in maintenance and construction; may cause skin and airway
irritation
(h) Bioaerosols: Include microbiologic agents which cause infections such as Legion-
naires disease, viral agents, common cold as well as allergens derived from pet
dander, dust mites, fungi and moulds that cause allergic rhinitis/asthma

Carbon Monoxide

• Important cause of accidental death due to oxygen deprivation (haemoglobin has 200
times higher affinity for CO than for O 2 ; besides, carboxyhaemoglobin interferes with
the release of oxygen from oxyhaemoglobin causing further tissue hypoxia)
• Diagnosis of CO poisoning confirmed by measuring carboxyhaemoglobin levels
• CO poisoning presents in two ways:
• Acute CO poisoning
• Cherry red skin and mucous membrane
• Petechial haemorrhages
• Hypoxic injury to brain, liver and renal tubules
• Chronic CO poisoning
• Diffuse neuronal loss and focal cerebral demyelination (CNS disturbances, hearing
loss, blindness and paralysis)
• May cause glomerulopathy and acute tubular necrosis (ATN)

Mercury

• Source: Industrial contamination of ocean (from bacteria to fish to humans) and paints
• Effects: CNS disturbances, hearing loss, blindness, spasticity, paralysis and glomerulopathy

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