Pathology Cheat Sheet
Exposure Leaves a Pathway
Environmental injury for NEET-PG exams: tobacco carcinogens, carbon monoxide, alcoholic liver disease, lead and arsenic toxicity, asbestos, and silicosis.
MedNext Academy | 3 min read
Exposure Leaves a Pathway
Environmental injury for NEET-PG exams: tobacco carcinogens, carbon monoxide, alcoholic liver disease, lead and arsenic toxicity, asbestos, and silicosis.
The pathogenesis of disease caused by air pollution, tobacco, and alcohol, tracing each exposure to its target tissue injury.
High-yield lines
- Environmental injury follows a common logic where a chemical or physical agent exceeds the adaptive capacity of cells.
- Tobacco smoke delivers nicotine for dependence plus carcinogens, carbon monoxide, and irritants.
- Smoking causes chronic obstructive pulmonary disease, squamous metaplasia, dysplasia, and carcinoma of the lung.
- Carbon monoxide binds haemoglobin with high affinity to form carboxyhaemoglobin, impairing oxygen delivery.
- Ethanol is metabolised to acetaldehyde with a redox shift and oxidative stress that injure the liver.
- Alcohol causes a sequence of fatty liver, alcoholic steatohepatitis, and cirrhosis.
- Alcohol also causes peripheral neuropathy, dilated cardiomyopathy, and fetal alcohol syndrome.
- Lead poisoning causes peripheral neuropathy, basophilic stippling of red cells, and impaired haem synthesis.
- Arsenic exposure causes skin keratoses, hyperpigmentation, and increased skin and visceral cancer risk.
- Air pollution particulates cause oxidant airway injury and worsen emphysema and cardiovascular disease.
- Asbestos exposure causes pleural plaques, asbestosis, bronchogenic carcinoma, and mesothelioma.
- Silica exposure causes silicotic nodules and increases susceptibility to tuberculosis.
Mapped competency codes
- PA12.1
Continue into the full chapter
This summary maps to PA12-environmental-and-nutritional-diseases.
Frequently Asked Questions
How does carbon monoxide cause tissue injury?
It binds haemoglobin with far greater affinity than oxygen to form carboxyhaemoglobin, reducing oxygen-carrying capacity and causing tissue hypoxia.
What is the sequence of alcoholic liver disease?
Fatty change (steatosis), followed by alcoholic steatohepatitis, and finally cirrhosis, driven by acetaldehyde and oxidative stress.
What lung diseases does smoking cause?
Chronic obstructive pulmonary disease and emphysema, along with squamous metaplasia progressing to dysplasia and bronchogenic carcinoma.
What are the effects of lead poisoning?
Peripheral motor neuropathy, basophilic stippling of red cells, anaemia from impaired haem synthesis, and abdominal colic.
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