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Lung Abscess Clinical Presentation

  • Author: Nader Kamangar, MD, FACP, FCCP, FCCM; Chief Editor: Ryland P Byrd, Jr, MD  more...
Updated: Dec 17, 2014


Symptoms depend on whether the abscess is caused by anaerobic or other bacterial infection. A lung abscess may be asymptomatic in a small proportion of patients in the early stages. Typical symptoms are below.

  • Anaerobic infection in lung abscess
    • Patients often present with indolent symptoms that evolve over a period of weeks to months.
    • The usual symptoms are fever, cough with sputum production, night sweats, anorexia, and weight loss.
    • The expectorated sputum characteristically is foul smelling and bad tasting.
    • Patients may develop hemoptysis or pleurisy
  • Other pathogens in lung abscess
    • These patients generally present with conditions that are more acute in nature and are usually treated while they have bacterial pneumonia.
    • Cavitation occurs subsequently as parenchymal necrosis ensues.
    • Abscesses from fungi, Nocardia species, and Mycobacteria species tend to have an indolent course and gradually progressive symptoms.


The findings on physical examination of a patient with lung abscess are variable. Physical findings may be secondary to associated conditions such as underlying pneumonia or pleural effusion. The physical examination findings may also vary depending on the organisms involved, the severity and extent of the disease, and the patient's health status and comorbidities.

  • Patients with lung abscesses may have low-grade fever in anaerobic infections and temperatures higher than 38.5°C in other infections.
  • Generally, patients with in lung abscess have evidence of gingivitis and/or periodontal disease.
  • Clinical findings of concomitant consolidation may be present (eg, decreased breath sounds, dullness to percussion, bronchial breath sounds, coarse inspiratory crackles).
  • The amphoric or cavernous breath sounds are only rarely elicited in modern practice.
  • Evidence of pleural friction rub and signs of associated pleural effusion, empyema, and pyopneumothorax may be present. Signs include dullness to percussion, contralateral shift of the mediastinum, and absent breath sounds over the effusion.
  • Digital clubbing may develop rapidly.


The bacterial infection may reach the lungs in several ways. The most common is aspiration of oropharyngeal contents.

  • Patients at the highest risk for developing lung abscess have the following risk factors:
    • Periodontal disease
    • Seizure disorder
    • Alcohol abuse
    • Dysphagia
  • Other patients at high risk for developing lung abscess include individuals with an inability to protect their airways from massive aspiration because of a diminished gag or cough reflex, caused by a state of impaired consciousness (eg, from alcohol or other CNS depressants, general anesthesia, or encephalopathy).
  • Infrequently, the following infectious etiologies of pneumonia may progress to parenchymal necrosis and lung abscess formation:
    • Pseudomonas aeruginosa
    • K pneumoniae
    • S aureus (may result in multiple abscesses)
    • Streptococcus pneumoniae
    • Nocardia species
    • Actinomyces species
    • Fungal species
  • An abscess may develop as an infectious complication of a preexisting bulla or lung cyst.
  • An abscess may develop secondary to carcinoma of the bronchus. The bronchial obstruction causes postobstructive pneumonia, which may lead to abscess formation.
Contributor Information and Disclosures

Nader Kamangar, MD, FACP, FCCP, FCCM Professor of Clinical Medicine, University of California, Los Angeles, David Geffen School of Medicine; Chief, Division of Pulmonary and Critical Care Medicine, Vice-Chair, Department of Medicine, Olive View-UCLA Medical Center

Nader Kamangar, MD, FACP, FCCP, FCCM is a member of the following medical societies: Academy of Persian Physicians, American Academy of Sleep Medicine, American Association for Bronchology and Interventional Pulmonology, American College of Chest Physicians, American College of Critical Care Medicine, American College of Physicians, American Lung Association, American Medical Association, American Thoracic Society, Association of Pulmonary and Critical Care Medicine Program Directors, Association of Specialty Professors, California Sleep Society, California Thoracic Society, Clerkship Directors in Internal Medicine, Society of Critical Care Medicine, Trudeau Society of Los Angeles, World Association for Bronchology and Interventional Pulmonology

Disclosure: Nothing to disclose.


Jason E Bahk, MD Resident Physician, Department of Internal Medicine, Olive View-UCLA Medical Center

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Ryland P Byrd, Jr, MD Professor of Medicine, Division of Pulmonary Disease and Critical Care Medicine, James H Quillen College of Medicine, East Tennessee State University

Ryland P Byrd, Jr, MD is a member of the following medical societies: American College of Chest Physicians, American Thoracic Society

Disclosure: Nothing to disclose.

Additional Contributors

Stephen P Peters, MD, PhD, FACP, FAAAAI, FCCP, FCPP Thomas H Davis Chair in Pulmonary Medicine, Chief, Section on Pulmonary, Critical Care, Allergy and Immunologic Diseases, Professor of Internal Medicine, Pediatrics, and Translational Science, Associate Director, Center for Genomics and Personalized Medicine Research, Wake Forest University School of Medicine; Executive Director of the Respiratory Service Line, Wake Forest Baptist Medical Center

Stephen P Peters, MD, PhD, FACP, FAAAAI, FCCP, FCPP is a member of the following medical societies: American Academy of Allergy Asthma and Immunology, American Association of Immunologists, American College of Chest Physicians, American College of Physicians, American Federation for Medical Research, American Thoracic Society, Sigma Xi

Disclosure: Serve(d) as a speaker or a member of a speakers bureau for: Integrity CE, Merck<br/>Received income in an amount equal to or greater than $250 from: – Array Biopharma, AstraZeneca, Aerocrine, Airsonett AB, Boehringer-Ingelheim, Experts in Asthma, Gilead, GlaxoSmithKline, Merck, Novartis, Ono Pharmaceuticals, Pfizer, PPD Development, Quintiles, Sunovion, Saatchi & Saatichi, Targacept, TEVA, Theron.


Curtis C Sather, MD Fellow, Divison of Pulmonary/Critical Care Medicine, Cedars-Sinai Medical Center

Curtis C Sather, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, American Medical Association, and American Thoracic Society

Disclosure: Nothing to disclose.

Sat Sharma, MD, FRCPC Professor and Head, Division of Pulmonary Medicine, Department of Internal Medicine, University of Manitoba; Site Director, Respiratory Medicine, St Boniface General Hospital

Sat Sharma, MD, FRCPC is a member of the following medical societies: American Academy of Sleep Medicine, American College of Chest Physicians, American College of Physicians-American Society of Internal Medicine, American Thoracic Society, Canadian Medical Association, Royal College of Physicians and Surgeons of Canada, Royal Society of Medicine, Society of Critical Care Medicine, and World Medical Association

Disclosure: Nothing to disclose.

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Histology of a lung abscess shows dense inflammatory reaction (low power).
A thick-walled lung abscess.
Pneumococcal pneumonia complicated by lung necrosis and abscess formation.
A lateral chest radiograph shows air-fluid level characteristic of lung abscess.
A 54-year-old patient developed cough with foul-smelling sputum production. A chest radiograph shows lung abscess in the left lower lobe, superior segment.
A 42-year-old man developed fever and production of foul-smelling sputum. He had a history of heavy alcohol use, and poor dentition was obvious on physical examination. Chest radiograph shows lung abscess in the posterior segment of the right upper lobe.
A 42-year-old man developed fever and production of foul-smelling sputum. He had a history of heavy alcohol use, and poor dentition was obvious on physical examination. Lung abscess in the posterior segment of the right upper lobe was demonstrated on chest radiograph. CT scan shows a thin-walled cavity with surrounding consolidation.
Chest radiograph of a patient who had foul-smelling and bad-tasting sputum, an almost diagnostic feature of anaerobic lung abscess.
Histology of a lung abscess shows dense inflammatory reaction (high power).
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