Lung Abscess

        A lung abscess is a lung infection accompanied by pus accumulation and tissue destruction. The abscess may be putrid (due to anaerobic bacteria) or nonputrid (due to anaerobes or aerobes), and often has a well-defined border. The availability of effective antibiotics has made lung abscesses much less common than they were in the past.
Causes of Lung Abscess
A lung abscess is a manifestation of necrotizing pneumonia, often the result of aspiration of oropharyngeal contents. Poor oral hygiene with dental or gingival (gum) disease is strongly associated with a putrid lung abscess. Septic pulmonary emboli commonly produce cavitary lesions. Infected cystic lung lesions and cavitating bronchial carcinoma must be distinguished from lung abscesses.
Signs and Symptoms of Lung Abscess
The clinical effects of lung abscess include a cough that may produce bloody, purulent, or foul-smelling sputum; pleuritic chest pain; dyspnea; excessive sweating; chills; fever; headache; malaise; diaphoresis; and weight loss. Complications include rupture into the pleural space, which results in empyema and, rarely, massive hemorrhage. A chronic lung abscess may cause localized bronchiectasis. Failure of an abscess to improve with antibiotic treatment suggests a possible underlying neoplasm or other causes of obstruction.
Diagnosis for Lung Abscess
The following tests are used to diagnose a lung abscess:
1. Auscultation of the chest may reveal crackles and decreased breath sounds.
2. Chest X-ray shows a localized infiltrate with one or more clear spaces, usually containing air-fluid levels.
3. Percutaneous aspiration of an abscess or bronchoscopy may be used to obtain cultures to identify the causative organism. Bronchoscopy is only used if abscess resolution is eventful and the patient's condition permits it.
4. Blood cultures, Gram stain, and culture of sputum are also used to detect the causative organism.
5. White blood cell count commonly exceeds 10,000/ul.
Treatment for Lung Abscess
Antibiotic therapy often lasts for months until radiographic resolution or definite stability occurs. Clindamycin is often the drug of choice. Symptoms usually disappear in a few weeks. Postural drainage may facilitate discharge of necrotic material into upper airways, where expectoration is possible; oxygen therapy may relieve hypoxemia. A poor response to therapy may require resection of the lesion or removal of the diseased section of the lung but is not considered routine due to the possibility of infectious spread. All patients need rigorous follow-up and serial chest X-rays.
Special Considerations and Prevention Tips for Lung Abscess
• To prevent a lung abscess in the unconscious patient and the patient with seizures, first prevent aspiration of secretions. Do this by suctioning the patient and by positioning him to promote drainage of secretions.
• Provide chest physiotherapy (including coughing and deep breathing).
• Increase fluid intake to loosen secretions, and provide a quiet, restful atmosphere.