Causes and Classification of Disease Underwood Ch 2 & 3.

Causes and Classification of Disease

• Underwood Ch 2 & 3

Major Classification

• Genetic

• Traumatic

• Infective

• Iatrogenic

• Degenerative

Based on Pathogenesis

• Congenital• Approximately 4-6%

of live births• Heart disease• Cleft palette & lip• ‘Genetic’ disorders

• Acquired• Infectious• Environmental• Trauma

Coarctation of the Aorta

Trisomy 21

Trisomy 18 -Edwards Syndrome

Here is a lateral cleft in a child with multiple congenital anomalies. In this case, the constellation of anomalies suggested a possible chromosomal anomaly, and a karyotype revealed 47, XY, +18 (trisomy 18).

Trisomy 13 - Patau's syndrome.

• tiny head ("microcephaly"), arhinencephaly ("abnormal limbic system"), tiny eyes ("microphthalmia"), polydactyly, and scrambled viscera. *Sometimes there is only one cerebral hemisphere ("holoprosencephaly") or even a single eye ("cyclops").

This is holoprosencephaly. The "alobar" form of holoprosencephaly is shown here in which there a single large ventricle, because there is no attempt to form separate cerebral hemispheres.

PULMONARY EMPHYSEMA (cf surgical

emphysema)

• In this condition there is enlargement of the small air spaces contained in the pulmonary acini.

• The alveolar walls lose their elasticity and the alveoli remain filled with air at the end of expiration.

• It is the most common chronic pulmonary disease (excluding asthma)

PULMONARY EMPHYSEMA

• frequently classified with chronic bronchitis because of the simultaneous occurrence of the two conditions

• the alveolar walls lose their elasticity, and they remain filled with air at the end of expiration.

PULMONARY EMPHYSEMA

• a genetic abnormality of the enzyme alpha1-antitrypsin (AAT) may contribute to the development of emphysema

• Cigarette smoking has an inhibitory effect on AAT, and accelerates the onset of emphysema.

This infiltrating ductal carcinoma of the breast is definitely infiltrating the surrounding breast. The central white area is very hard and gritty, because the neoplasm is producing a desmoplastic reaction with lots of collagen. This is often called a "scirrhous" appearance. There is also focal dystrophic calcification leading to the gritty areas.

Many, if not most, people living in today's world have met the TB bacillus, but most never become sick. The tuberculin ("Mantoux") skin test turns positive in any normal person whose T-cells have met the tubercle bacillus. Tuberculosis remains primarily a disease of poverty, crowding, malnutrition, and lack of health care.

Miliary Tb of the Lung

Bronchopneumonia

Today, tobacco smoke is the most widespread of the known pollutants. In developed countries, ethanol and tobacco are the two principal causes of avoidable death.

Tobacco smoke is a complex mixture that contains nicotine (the addictive component) and many other harmful substances, including carbon monoxide, benzopyrene (* mutates ras codon 12 G-->T; Cancer 72: 432, 1993), nickel, polonium, and radon.

"Low-tar" and "low nicotine" cigarettes are not measurably less dangerous than the regular kind. Smoking without inhaling (pipes, cigars) is less addictive and easier on the lungs, but the risk of mouth and throat cancer is high.

After high serum cholesterol, cigarette smoking is the most important risk factor for coronary heart disease (heart attacks, sudden death, angina pectoris -- see Chest 94: 449, 1988) and other complications of atherosclerosis (including ruptured aortic aneurysms and strokes.

Mortality

• Chronic bronchitis and emphysema (together, "chronic obstructive pulmonary disease") kill 150,000 people in the US each year.

• Lung cancer kills 140,000 people in the US each year.

• Cures are rare.

The vast majority of these cancers are caused by cigarette smoking.

• Mouth cancer, throat cancer, larynx cancer, and esophageal cancer are all strongly associated with tobacco smoking.

• Bladder cancer rates are roughly tripled for cigarette smokers. Pancreatic cancer and kidney cancer rates are at least doubled for cigarette smokers.

There is no longer any reasonable doubt that passive smoking (inhaling someone else's cigarette smoke) is dangerous. Passive smoking probably causes around 5000 cancers yearly in the US