Pathology
Environmental and Nutritional Diseases
Environmental and nutritional diseases for MBBS and NEET-PG: tobacco and alcohol effects, protein-energy malnutrition, vitamin deficiencies and obesity, mapped to NMC codes PA12.1 to PA12.3.
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Environmental and Nutritional Diseases
Environmental and nutritional diseases for MBBS and NEET-PG: tobacco and alcohol effects, protein-energy malnutrition, vitamin deficiencies and obesity, mapped to NMC codes PA12.1 to PA12.3.
This chapter deals with disease caused by the environment and by disordered nutrition. It covers the effects of air pollution, tobacco and alcohol, the pathology of protein-energy malnutrition and vitamin deficiencies, and the growing burden of obesity and its complications.
High-yield: Environmental and Nutritional Diseases
- Tobacco smoking is the single most important preventable cause of cancer, especially of the lung, and also causes cardiovascular and chronic lung disease.
- Cigarette smoke contains carcinogens such as polycyclic aromatic hydrocarbons and nitrosamines.
- Chronic alcohol use damages the liver in three stages: fatty change, alcoholic hepatitis and cirrhosis.
- Alcohol also causes pancreatitis, cardiomyopathy, Wernicke encephalopathy and an increased risk of upper aerodigestive cancers.
- Air pollutants and occupational dusts cause pneumoconioses such as silicosis, asbestosis and coal worker lung disease.
- Asbestos exposure predisposes to bronchogenic carcinoma and to malignant mesothelioma of the pleura.
- Protein-energy malnutrition presents as marasmus (severe wasting) or kwashiorkor (oedema and hypoalbuminaemia).
- Kwashiorkor shows oedema, a distended fatty liver, skin and hair changes and a relatively preserved but sad appearance.
- Marasmus shows severe muscle and fat wasting with a wizened old-man appearance and no oedema.
- Vitamin A deficiency causes night blindness, xerophthalmia and Bitot spots on the conjunctiva.
- Vitamin D deficiency causes rickets in children and osteomalacia in adults.
- Vitamin C deficiency causes scurvy with impaired collagen synthesis, bleeding gums and poor wound healing.
- Obesity, defined by a raised body mass index, increases the risk of type 2 diabetes, hypertension, ischaemic heart disease and several cancers.
- Central (visceral) obesity is more strongly linked to insulin resistance and metabolic syndrome than peripheral fat.
- Lead poisoning causes anaemia with basophilic stippling, a peripheral neuropathy and, in children, encephalopathy.
Marasmus versus kwashiorkor
- **Marasmus:** Severe energy deficit; gross wasting of fat and muscle; no oedema; old-man look.
- **Kwashiorkor:** Protein deficit; oedema; fatty liver; skin and hair changes; low albumin.
- **Tobacco:** Leading preventable cause of cancer, especially lung; cardiovascular and lung disease.
- **Alcohol:** Fatty liver, hepatitis, cirrhosis, pancreatitis and cardiomyopathy.
NMC competencies in this chapter
- **PA12.1:** Pathogenesis of disorders caused by air pollution, tobacco and alcohol
- **PA12.2:** Pathogenesis of disorders of protein-calorie malnutrition and starvation
- **PA12.3:** Pathogenesis of obesity and its consequences
Frequently Asked Questions
How does marasmus differ from kwashiorkor?
Marasmus is a severe energy deficit with gross wasting and no oedema, while kwashiorkor is predominantly protein deficiency with oedema, a fatty liver and low albumin.
Why is tobacco so important in pathology?
Tobacco is the leading preventable cause of cancer, especially lung cancer, and also a major cause of cardiovascular and chronic obstructive lung disease.
What are the stages of alcoholic liver disease?
Fatty change first, then alcoholic hepatitis, and finally cirrhosis, which may be irreversible.
What conditions is obesity linked to?
Type 2 diabetes, hypertension, ischaemic heart disease, obstructive sleep apnoea and several cancers, especially with central visceral fat.
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