para>Staphylococcus is the most common organism in children. � �
ETIOLOGY AND PATHOPHYSIOLOGY
- May be due to aspiration of anaerobic oral flora (most common); 24 to 48 hours after aspiration, lung abscess forms.
- Less commonly, septic emboli from endocarditis and others (1)[B],(2,3)[C]
- Usually mixed flora with predominance of anaerobes
- Oral flora anaerobes (60 " �75% of cases)
- Peptostreptococcus
- Prevotella
- Fusobacterium
- Bacteroides sp.
- Aerobes (10 " �20%)
- Staphylococcus aureus
- Streptococcus pyogenes
- Klebsiella sp.
- Pseudomonas aeruginosa
- Streptococcus milleri
- Atypical aerobes
- Actinomyces
Genetics
- No known genetic pattern
- Immunodeficiency associated with FCN3 mutation and ficolin-3 deficiency may predispose patients to lung infections (1)[B].
RISK FACTORS
- Periodontal disease (gingivitis), dental abscess, dental surgery
- Risk for aspiration
- Alcohol intoxication (loss of consciousness) is the most common cause of aspiration.
- Epilepsy
- Cerebrovascular accident with oropharyngeal dysfunction
- Sinusitis
- General anesthesia with surgery
- Dysphagia
- Tracheal/nasogastric tube
- Severe gastroesophageal reflux disease
- Cerebral palsy
- Large bacterial burden
- Necrotizing pneumonia
- Bacteremia (especially Staphylococcus)
- Septic embolism (especially in endocarditis)
- Disseminated septic phlebitis
- Airway obstruction
- Bronchial stenosis
- Pulmonary embolism
- Cavitary infarction
- Lung neoplasia
- Enlarged lymph node
- Foreign body: stent-associated respiratory tract infection
- Immunocompromised
- Diabetes mellitus
- HIV infection
- Chronic steroid use
- Amoebic lung abscess: most often from direct extension from liver abscess through the diaphragm to the right lower lobe
GENERAL PREVENTION
- Treatment of predisposing diseases
- Aspiration precautions
- Treatment of periodontal diseases
COMMONLY ASSOCIATED CONDITIONS
- Periodontal disease
- Pneumonia
- Alcoholism
- Empyema (if necrosis of the abscess wall allows entry into pleural space)
- Posttraumatic empyema (4)[B]
- Tuberculosis
- Immunocompromised patient
DIAGNOSIS
HISTORY
- Fever
- Malaise
- Diaphoresis
- Night sweats
- Anorexia
- Weight loss
- Dyspnea
- Chest pain/pleurisy
- Cough with purulent, foul-smelling, putrid, sour-tasting sputum
- Hemoptysis
PHYSICAL EXAM
- Vital signs: tachypnea, tachycardia
- Lung exam
- Decreased breath sounds
- Cavernous breath sounds
- Crackles
- Wheezing
- Dullness to percussion
- Consolidation by auscultation
- Clubbing of digits
ALERT
The posterior segment of the right upper lobe is the most common location for a lung abscess.
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DIFFERENTIAL DIAGNOSIS
- Bronchogenic carcinoma
- Bronchiectasis
- Empyema with bronchopulmonary fistula
- Tuberculosis
- Mycotic lung infections
- Vasculitis
- Parasitic lung infections
- Infected pulmonary bulla
- Wegener granulomatosis
- Pulmonary sequestration
- Subphrenic or hepatic abscess with perforation into a bronchus
- Bronchogenic or parenchymal cyst
- Aspirated foreign body
DIAGNOSTIC TESTS & INTERPRETATION
- CBC shows leukocytosis and anemia.
- Hypoalbuminemia
- Sputum smear: neutrophils, mixed bacteria
- Sputum culture: often grows normal respiratory flora; may help in atypical presentations
- Blood culture: often negative in anaerobic abscess
- Drugs that may alter lab results: prior antibiotics
- Chest x-ray
- Lung cavity with air " �fluid level
- Consolidation with radiolucency, infiltrates, pleural effusion, mediastinal adenopathy
- Ultrasound (US)
- Color Doppler US: Great sensitivity, specificity, positive predictive value, and negative predictive value when identification of vessel signals in a pericavitary consolidation is achieved.
- Computed tomography scan
- Defines location and extent (typical location depends on segments such as posterior segments of upper lobes or superior segments of lower lobes)
- May detect obstructing lesion
- May demonstrate cavitary opacities
- May show multiple thrombus of neck vessels (infectious thrombophlebitis) (5)[B]
Diagnostic Procedures/Other
- Bronchoscopy if obstruction is suspected
- Bronchoscopic brushing
- Bronchoalveolar lavage
- Transthoracic needle aspiration (rarely done)
- Percutaneous catheter " �guided drainage (6)[B]
Test Interpretation
- Solitary abscess
- Multiple abscesses
- Cavitation with necrosis
- Effusion/empyema
TREATMENT
GENERAL MEASURES
- Postural drainage
- Nasotracheal suctioning if needed
- Prolonged course of antibiotics
- Pulmonary physiotherapy
- Bronchoscopy with selective therapeutic lavage (rarely done)
- In general, 10% require surgical intervention, such as drainage of abscess or empyema.
MEDICATION
First Line
Antibiotics according to culture and sensitivity results; for presumed anaerobes, clindamycin 600 mg q6 " �8h IV followed by 300 mg q6h PO for 4 weeks � �
Second Line
- Historically, standard therapy had been penicillin G 1 to 2 million units IV q4h until improvement, followed by 1.2 million units (750 mg) PO q6h times for 3 to 4 weeks; now, many relevant pathogens produce � �-lactamase.
- Cefoxitin 2 g IV q6 " �8h
- Piperacillin-tazobactam 3.375 g IV q6h
- Ticarcillin-clavulanate 3.1 g IV q6h
- Metronidazole has not proven as effective as clindamycin but often is recommended for use as an adjunctive therapy (500 mg IV q6h).
- Full course of therapy may be needed for up to 8 weeks.
SURGERY/OTHER PROCEDURES
- Antibiotic treatment is successful in most patients; surgical options are considered when medical therapy fails.
- Endoscopic drainage
- Tube thoracostomy with medical failure or prohibitive operative risk
- Thoracoscopic drainage (7)[B]
- Percutaneous catheter " �guided drainage (6)[B]
- Pulmonary resection only if complications occur or if patient fails therapy (mortality 11 " �16%)
- Vacuum-assisted closure may be used in debilitated patients.
INPATIENT CONSIDERATIONS
Admission Criteria/Initial Stabilization
Inpatient care for monitoring and treatment � �
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Activity reduced until radiographic evidence of clearing � �
Patient Monitoring
Serial radiographs until resolution of cavity � �
DIET
No restrictions � �
PATIENT EDUCATION
- Pulmonary physiotherapy techniques
- American Academy of Family Physicians at http://www.aafp.org/home.html
- American Lung Association: possible complications of pneumonia: http://www.lung.org/lung-health-and-diseases/lung-disease-lookup/pneumonia/learn-about-pneumonia.html
PROGNOSIS
- Clinical improvement with decrease in fever expected 3 to 4 days after starting antibiotics
- Defervescence is expected in 7 to 10 days.
- Prognosis depends on the underlying disease or immunosuppression.
- Patients with primary abscess (otherwise healthy, typical aspiration) have cure rates of 90 " �95%.
- Certain factors tend to have worse prognosis:
- Large abscess (>6 cm)
- Anatomic obstruction
- Right lower lobe location
- Certain bacteriologic species: S. aureus, Klebsiella, Pseudomonas
- Overall mortality 15 " �20%
- Patients with secondary abscess (underlying neoplasm, obstruction, HIV) have 75% mortality.
Geriatric Considerations
Mortality higher in the elderly
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COMPLICATIONS
- Extension
- Empyema
- Massive hemoptysis
- Pneumothorax
- Brain abscess
REFERENCES
11 Munthe-Fog � �L, Hummelsh � �j � �T, Honore � �C, et al. Immunodeficiency associated with FCN3 mutation and ficolin-3 deficiency. N Engl J Med. 2009;360(25):2637 " �2644.22 Chirinos � �JA, Garcia � �J, Alcaide � �ML, et al. Septic thrombophlebitis: diagnosis and management. Am J Cardiovasc Drugs. 2006;6(1):9 " �14.33 Mawdsley � �JE, Maleki � �N, Benjamin � �E, et al. Oesophageal perforation with asymptomatic lung abscess formation. Lancet. 2006;368(9552):2104.44 O 'Connor � �JV, Chi � �A, Joshi � �M, et al. Post-traumatic empyema: aetiology, surgery and outcome in 125 consecutive patients. Injury. 2012;44(9):1153 " �1158.55 Velagapudi � �P, Turagam � �M, Are � �C, et al. "A forgotten disease " �: a case of Lemierre syndrome. ScientificWorldJournal. 2009;9:331 " �332.66 Chen � �CH, Chen � �W, Chen � �HJ, et al. Transthoracic ultrasonography in predicting the outcome of small-bore catheter drainage in empyemas or complicated parapneumonic effusions. Ultrasound Med Biol. 2009;35(9):1468 " �1474.77 Nagasawa � �KK, Johnson � �SM. Thoracoscopic treatment of pediatric lung abscesses. J Pediatr Surg. 2010;45(3):574 " �578.
ADDITIONAL READING
- Bartlett � �JG. How important are anaerobic bacteria in aspiration pneumonia: when should they be treated and what is optimal therapy. Infect Dis Clin North Am. 2013;27(1):149 " �155.
- Desai � �H, Agrawal � �A. Pulmonary emergencies: pneumonia, acute respiratory distress syndrome, lung abscess, and empyema. Med Clin North Am. 2012; 96(6):1127 " �1148.
- Huang � �CT, Chen � �CY, Ho � �CC, et al. A rare constellation of empyema, lung abscess, and mediastinal abscess as a complication of endobronchial ultrasound-guided transbronchial needle aspiration. Eur J Cardiothorac Surg. 2011;40(1):264 " �265.
- Medford � �AR, Bennett � �JA, Free � �CM, et al. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA): applications in chest disease. Respirology. 2010;15(1):71 " �79.
- Sziklavari � �Z, Ried � �M, Hofmann � �HS. Vacuum-assisted closure therapy in the management of lung abscess. J Cardiothorac Surg. 2014;9(1):157.
SEE ALSO
Pneumonia, Bacterial � �
CODES
ICD10
- J85.2 Abscess of lung without pneumonia
- J85.1 Abscess of lung with pneumonia
- A06.5 Amebic lung abscess
- J85.3 Abscess of mediastinum
ICD9
- 513.0 Abscess of lung
- 006.4 Amebic lung abscess
- 513.1 Abscess of mediastinum
SNOMED
- Abscess of lung (disorder)
- abscess of lung with pneumonia (disorder)
- Amebic lung abscess (disorder)
- Abscess of mediastinum
- Tuberculous abscess of lung (disorder)
- Abscess of lung and mediastinum
CLINICAL PEARLS
- Bacteria are carried to the dependent portions of the lung, with the posterior segment of the right upper lobe being the most common location for abscess.
- Percutaneous drainage and surgical resection could be considered treatment options when medical therapy fails. Endoscopic drainage techniques show promise as an alternative.
- Lemierre syndrome is a complication of Fusobacterium necrophorum oropharyngeal infection (usually pharyngitis). The infection extends to the internal jugular vein, causing thrombophlebitis. The thrombophlebitis, in turn, produces septic emboli, including emboli that produce lung abscess or pneumonia (2)[C].