Pneumonia is a lung infection often caused by viruses or bacteria, according to the American Lung Association. People with weakened immune systems or pre-existing respiratory diseases have the highest risk of contracting pneumonia. Bronchitis is an inflammatory disease that constricts the bronchial tubes and reduces airflow throughout the respiratory system, states the National Heart, Lung, and Blood Institute. Smokers and adults over 45 are most likely to develop bronchitis.
Pneumonia is often preceded by other illnesses, including bronchitis. Air sacs in the lungs become infected and filled with liquid, restricting a person's ability to breathe, according to the American Lung Association. Pneumonia suffers typically develop a mucus-producing cough and fever symptoms, such as chills, notes WebMD. While pneumonia is frequently diagnosed using chest X-rays, bronchitis displays physical symptoms that are very similar to other respiratory conditions.
Bronchitis occurs when irritants, such as bacteria, dust or smoke, are inhaled into the bronchial tubes, inflaming the tissue lining, according to the National Heart, Lung, and Blood Institute. Bronchitis can trigger fevers, persistent coughing, mucus buildup and wheezing, and individuals who already have a cold or the flu experience additional symptoms caused by the viruses. Acute, or short-term, bronchitis usually clears up within three weeks, but pneumonia symptoms may last longer, reports WebMD.