Aspiration pneumonia and pneumonitis

Aspiration pneumonia and pneumonitis are caused by aspiration of toxic substances, usually gastric contents, into the lungs. The result can be unidentifiable or chemical pneumonitis, bacterial pneumonia or airway obstruction. Symptoms of aspiration pneumonia include coughing and shortness of breath. The diagnosis is based on a clinical picture and radiography. Treatment of aspiration pneumonia and prognosis depend on the aspirated substance.

Aspiration with liquid (for example, with drowning) or with solid food causes a number of complications, from atelectasis to hypoxemia and death. The diagnosis is obvious from an anamnesis; treatment involves aspiration of fluid or bronchoscopic removal of food, if possible. If the food can not be completely removed, glucocorticoids are sometimes prescribed, but their effectiveness in such situations is not proven.

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Causes of the aspiration pneumonia

Many substances are either directly toxic to the lung, or stimulate an inflammatory reaction after aspiration; An example is gastric acid, but other substances, in particular oil products (petroleum jelly) and liquid oils (mineral oil or kerosene), which cause lipoid pneumonia, can also cause chemical pneumonitis.

Damage to the lungs with aspiration of gastric contents occurs mainly due to the presence of hydrochloric acid, although other components of the stomach contents (food, activated charcoal, taken in the treatment of overdoses) can also have an aggressive effect. Gastric acid causes a chemical burn of the respiratory tract and lung, leading to rapid bronchospasm, atelectasis, edema and alveolar bleeding. Symptoms include acute dyspnoea with a cough, sometimes productive with the release of pink foamy sputum; tachypnea; tachycardia; fever; diffuse crackling rales. Chest X-ray demonstrates often diffuse infiltrates, but not exclusively in dependent segments, while pulse oximetry and blood gas analysis demonstrate hypoxemia. Supportive treatment is carried out, artificial ventilation is often required. Antibiotics are usually prescribed for patients whose aspiration of gastric contents is confirmed by reliable evidence. The syndrome can be resolved spontaneously, usually for several days; may progress to acute respiratory distress syndrome and / or may be complicated by bacterial superinfection.

Aspiration of oils or petrolatum causes exogenous lipoid pneumonia, which is histologically characterized by chronic granulomatous inflammation with fibrosis. It often occurs asymptomatically and is detected accidentally on chest radiography or may manifest as a slight increase in temperature, gradual loss of body weight and wheezing. Chest x-ray results change; consolidation, cavitation, interstitial or nodular infiltration, pleural effusion and other changes can slowly progress. Treatment is to eliminate toxic effects.

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Risk factors

The risk of aspiration occurs with impaired consciousness, difficulty swallowing, vomiting, the presence of gastrointestinal or endotracheal tubes, or appropriate procedures, gastroesophageal reflux disease.

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Symptoms of the aspiration pneumonia

Aspiration pneumonia and abscess have similar symptoms - chronic mild dyspnea, fever, weight loss and cough, productive, with the release of putrefactive sputum of unpleasant taste. There may be signs of poor oral hygiene.

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Complications and consequences

Healthy people often aspirate small amounts of oral secretion, but normal protective mechanisms clean the airways without complications. Aspiration of large quantities or aspiration in a patient with reduced pulmonary protection often causes pneumonia and / or an abscess.

Aspiration can cause lung inflammation (chemical pneumonitis), infection (bacterial pneumonia or abscess), or airway obstruction. Most episodes of aspiration cause minor symptoms or pneumonitis, rather than infection or obstruction.

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Diagnostics of the aspiration pneumonia

Chest X-ray reveals infiltration, often, but not exclusively, in the dependent segments of the lung, i.e. In the upper segment of the lower lobe or posterior segment of the upper lobe. Anxerobes are often secreted from the sputum, but it is unclear whether they are the main pathogens of the infection to be treated, or simply one of several types of microorganisms that cause infection.

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Treatment of the aspiration pneumonia

Treatment of aspiration pneumonia is performed with clindamycin in a dose of 450 to 900 mg intravenously every 8 hours, then orally 300 mg 4 times a day until the disappearance of fever and clinical symptoms. Penicillin (or penicillin G in a dose of 1-2 million units every 4-6 hours, or amoxicillin 0.5-1 g orally 3 times a day) plus metronidazole orally 3 times a day for 500 mg or amoxicillin-clavulanate 1.2 g 3 times a day intravenously, then 875 mg / 125 mg orally 2 times a day or imipenem intravenously 500 mg 4 times a day are acceptable alternative kpindamycin. The duration of treatment is usually 1-2 weeks, if pneumonia is not complicated by the formation of lung abscess; in this case, the treatment of aspiration pneumonia can continue for 6 weeks and up to 3 months. Empyema is another frequent complication.