Aspiration Pneumonia
Tiny particles from the mouth frequently dribble or are inhaled (aspirated) into the airways, but usually they are cleared out by normal defense mechanisms before they can get into the lungs and cause inflammation or infection. When such particles are not cleared, they can cause aspiration pneumonia. Older people and people who are debilitated, intoxicated by alcohol or drugs, or unconscious from anesthesia or a medical condition are especially at risk for this type of pneumonia. Even a healthy person who inhales a large amount of material, as may happen during vomiting, can develop aspiration pneumonia.
Symptoms of pneumonia do not begin for at least a day or two. Treatment requires antibiotics. Many antibiotics can be used, but treatment often begins with clindamycin or metronidazole plus penicillin. If a solid particle was inhaled, a bronchoscopy may be needed to remove it (see Section 4, Chapter 39).
Chemical pneumonitis occurs when a person inhales (aspirates) material that is toxic to the lungs; the problem is more the result of irritation than infection. A commonly inhaled toxic material is stomach acid, so that chemical pneumonitis may result whenever a person inhales what has been vomited up. Sudden shortness of breath and a cough develop within minutes or hours. Other symptoms may include fever and pink frothy sputum. In less severe cases, the symptoms of aspiration pneumonia may follow a day or two later.
The diagnosis of chemical pneumonitis is usually obvious from the sequence of events. Chest x-rays and measurements of oxygen concentrations in arterial blood may help. When the diagnosis remains unclear, a bronchoscopy is sometimes performed.
Treatment consists of oxygen therapy (see Section 4, Chapter 40) and mechanical ventilation (see Section 4, Chapter 50) if necessary. The trachea may be suctioned to clear secretions and aspirated food particles out of the airways. Bronchoscopy may also be used for this purpose.
Antibiotics are usually given because doctors cannot easily distinguish this form of aspiration pneumonia from a bacterial infection. Generally, people with chemical pneumonitis either recover rapidly, progress to acute respiratory distress syndrome, or develop a bacterial infection. Up to 30 to 50% of people with serious chemical pneumonitis die.
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