If not treated with antibiotics, it may lead to rheumatic fever which can damage heart valves. Most forms caused by bacteria or viruses. AIDS patients may have pneumonia due to protozoan Pneumocystis carinii . Caused by tubercle bacilli that invade lung tissue. Skin test detects immunity developed due to previous exposure.
Air is trapped in alveoli which often causes rupturing of alveolar walls.
Lack of oxygen to brain causes depression, irritability, etc. Fibrous connective tissue builds up in lungs. Breathing is impaired, and the development of cancer is common. Women Catch Up i. Callused cells thicken to block bronchi.