References:
- Brunner & Suddarth’s Textbook of Medical-Surgical Nursing, 15th Edition, ISBN 978-197-51-6103-3, by Janice L. Hinkle, Kerry H. Cheever, and Kristen J. Overbaugh (Ch. 19, pp. [ebook] 1588–1591)
A lung abscess is a localized collection of pus caused by microbial infection. By definition, a chest x-ray demonstrates a cavity of at least 2 cm. Patients who are at risk for aspiration of foreign material and development of a lung abscess include those with impaired cough reflexes who cannot close the glottis and those with swallowing difficulties. Others include those with central nervous system disorders (e.g., seizure, stroke), substance use disorder, esophageal disease, or compromised immune function; patients without teeth and those receiving nasogastric tube feedings; and patients with an altered state of consciousness due to anesthesia.
Pathophysiology
Most lung abscesses are a complication of bacterial pneumonia or are caused by aspiration of oral anaerobes into the lung. Aerobic organisms may be involved as well. Abscesses also may occur secondary to mechanical or functional obstruction of the bronchi by a tumor, foreign body, or bronchial stenosis, or from necrotizing pneumonias, TB, pulmonary embolism (PE), or chest trauma.
- Location: most lung abscesses are found in areas of the lung that may be affected by aspiration, and is related to gravity—determined by position. For patients confined to bed, the posterior segment of an upper lobe and the superior segment of the lower lobe are the most common areas. However, atypical presentations may occur, depending on the position of the patient when the aspiration occurred.
- Communication: the abscess initially may or may not extend directly into a bronchus. Eventually, the abscess becomes surrounded (encapsulated) by a wall of fibrous tissue. The necrotic process may extend until it reaches the lumen of a bronchus or the pleural cavity, or both. - If the abscess reaches the bronchus, purulent contents spill into the bronchus and are expectorated continuously in the form of mucopurulent/purulent sputum. - If the abscess reaches the pleura, the abscess results in empyema. - If the abscess reaches both, a bronchopleural fistula is formed.
Clinical Manifestations
Clinical manifestations vary from a mild productive cough to acute illness. Most patients have a fever and a productive cough with moderate to copious amounts of foul-smelling, sometimes bloody, sputum.
- The fever and cough may develop insidiously and may have been present for several weeks before diagnosis.
- Leukocytosis may be present.
- Pleurisy or dull chest pain, dyspnea, weakness, anorexia, and weight loss are common.
Assessment and Diagnostic Findings
- Percussion: dullness.
- Auscultation: decreased or absent breath sounds, intermittent pleural friction rub, crackles may be present.
- Confirmatory diagnosis may be done with a chest x-ray, sputum culture, and, in some cases, fiberoptic bronchoscopy.
- The chest x-ray reveals an infiltrate with air-fluid level (infiltration that shows a clear line between the air and fluid within a cavity).
- A computed tomography (CT) scan of the chest may be required to provide more detailed images of different cross-sectional areas of the lung.
Prevention
The following measures reduce the risk of lung abscess:
- Appropriate antibiotic therapy before any dental procedures in patients who must have teeth extracted while their gums and teeth are infected.
- Adequate dental and oral hygiene, because anaerobic bacteria play a role in the pathogenesis of lung abscess.
- Appropriate antimicrobial therapy for patients with pneumonia.
Medical Management
The findings of the history, physical examination, chest x-ray, and sputum culture indicate the type of organism and the treatment required.
- Adequate drainage of the lung abscess may be achieved through postural drainage and chest physiotherapy.
- Patients should be assessed for an adequate cough.
- Some patients require the insertion of a percutaneous chest catheter for long-term drainage of the abscess.
- Bronchoscopy used to drain an abscess is possible, but is uncommon.
- A diet high in protein and calories is necessary, because chronic infection is associated with a catabolic state, necessitating increased intake of calories and protein to facilitate healing.
- Surgical intervention is rare, but pulmonary resection (lobectomy) is performed if massive hemoptysis occurs or if there is little or no response to medical management.
IV Antimicrobial Therapy
IV antimicrobial therapy depends on the results of the sputum culture and sensitivity and is given for an extended period. Large IV doses are usually required, because the antibiotic must penetrate the necrotic tissue and the fluid in the abscess.
- Standard treatment of an anaerobic lung infection is clindamycin, ampicillin-sulbactam, or carbapenem.
Duration of therapy remains controversial (2019). It may continue for 3 weeks or longer, depending upon the clinical severity and organism involved. Improvement is demonstrated by normal temperature, decreased white blood cell count, and improvement on chest x-ray (resolution of surrounding infiltrate, reduction in cavity size, and absence of fluid). Once improvement is demonstrated, IV antibiotics are discontinued and oral administration of antibiotic therapy is continued for an additional 4 to 12 weeks and sometimes longer. If treatment is stopped too soon, a relapse may occur.
Nursing Management
- The nurse administers antibiotics and IV treatments as prescribed and monitors for adverse effects.
- CPT (percussion, postural drainage) is initiated as prescribed to facilitate drainage of the abscess.
- The patient is educated on how to perform deep-breathing and coughing exercises to help expand the lungs.
- To ensure proper nutritional intake, the nurse encourages a diet that is high in protein and calories.
- The nurse also offers emotional support, because the abscess may take a long time to resolve.