Alternate Names: Aspiration pneumonia; Anaerobic pneumonia; Aspiration of vomitus; Necrotizing pneumonia; Pyogenic pneumonia

Causes and Risks: Aspiration of foreign material (often the stomach contents) into the lung can be a result of disorders that affect normal swallowing, disorders of the esophagus (esophageal stricture, gastroesophageal reflux), or decreased or absent gag reflex ( in unconscious, or semi-conscious individuals). Old age, dental problems, use of sedative drugs, anesthesia, coma, and excessive alcohol consumption are also causing or contributing factors. The response of the lungs depends upon the characteristics and amount of the aspirated substance. The more acidic the material, the greater the degree of lung injury. Aspiration of gastric contents is one of the leading causes of adult respiratory distress syndrome (flooding of the lungs with fluid).

The injured lungs can become infected with multiple species of anaerobic bacteria or aerobic bacteria. A collection of pus, from white blood cells that have been carried to the area to fight infection and from the microorganisms causing the infection, forms in the lung. A protective membrane may form around the abscess. The incidence of pneumonia with lung abscess is 6 out of 100,000 people.

Prevention:

• awareness of the risk of aspiration
• good dental hygiene

Symptoms:

• fever
  • present for 2 weeks or longer
• weight loss
• fatigue
• cough
  • with foul-smelling sputum
  • with sputum containing pus or blood
  • with greenish sputum
• shortness of breath
• bluish discoloration of the skin caused by lack of oxygen
• rapid pulse (heart rate)
• wheezing
• rales
• abnormal (high pitched) breathing sounds (may occur)

• sweating, excessive
• swallowing difficulty
• nail abnormalities
• joint swelling
• joint stiffness
• coughing up blood
• chills
• chest pain
• breath odor
• bone pain or tenderness

Signs and Tests: Physical examination reveals crackling sounds with stethoscope.

These tests also help diagnose this condition:

• a CBC
• arterial blood gas
• blood culture
• bronchoscopy
• chest X-ray
• lung needle biopsy with culture
• open lung biopsy
• sputum culture

Treatment: Hospitalization is usually required for management of the illness. Treatment measures vary depending on the severity of the pneumonia. The objective of treatment is to control the infection by antibiotic therapy until improvement in chest X-ray is demonstrated.

Intubation of the airway (endotracheal tube passed through the nose or mouth through the trachea) may be required to keep the airway open and to deliver oxygen directly to the lungs. Mechanical ventilation (a respirator) may be used in the critically ill who cannot breathe adequately on their own. The ventilator attaches directly to the endotracheal tube. Air and oxygen are delivered to the patient by hoses connected to the ventilator according to the need of the patient. As improvement occurs, a patient is gradually weaned from the machine.

Suctioning of secretions that build up in the lungs via mouth or endotracheal tube is necessary to keep the airway clear.

Medications such as antibiotics to treat infection and bronchodilators to keep the airway open are often indicated.

Chest tube placement to drain the infection from the pleural space may be necessary to control the infection.

Prognosis: The outcome depends on the severity of the pneumonia. If acute respiratory failure develops, the patient may have a prolonged illness or die. Healing may take as long as 6 to 12 months.

Complications:

• pneumothorax
• spread of infection to the blood stream (septicemia)
• spread of infection to other areas of the body
• low blood pressure
• shock
• adult respiratory distress syndrome
• pneumonia with lung abscess

Call your health care provider, go to the emergency room, or call the local emergency number (such as 911) if shortness of breath, wheezing, chills, fever, or fainting spells occur.