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Do you feel difficulty in breathing; and are not able to spit the cough? Well, you might be suffering from a lung abscess. 

So, what is a lung abscess?

Lung Abscess is a cavity filled with pus and fluid encircled with inflamed tissues in the lungs. Bacteria present in the mouth are the most common cause of lung abscession. The bacteria travels down the throat into the lungs due to breathing. Thus, it gives it a chance to start infection and form cavities. 

Lung abscess cavities are usually the size of 2cm. While cavities smaller than 2cm also are observed, these are called necrotizing pneumonia. Necrotizing pneumonia and abscess are both the results of microbial infection and affect the pulmonary tissues of the lungs. 

So, how does it develop?

Lung abscession is a progressive medical condition and does not appear in a day. 

Firstly, It forms a circumscribed section of necrotic debris and pus in the lungs’ parenchyma. Secondly, cavities are formed in the walls of the lungs; which leads to a bronchopulmonary fistula. Finally, it leads to the emergence of an air-fluid interface in the lung cavity. 

These were the general insight into lung abscess. However, this blog will enlighten you with the details of lung abscesses and what you need to know.

History of Lung Abscess:

Let’s start with the history. 

The discovery of the symptoms and treatment of lung abscess dates back to Hippocrates. 

It was the time of the pre-antibiotic era, so one-third of the infected people would die. Only one-third of patients would recover fully, while others had occasional complications. As there were no antibiotics, surgery was the sole therapy for curing lung abscesses. 

The mortality rate a few decades back was about 75% of infected people. Open drainage of the disease dropped the mortality rate to around 20-35%. With the emergence of antibiotics in the market, the mortality rate declined to an all-time low of 8.7%. 

The microbes responsible for causing lung abscesses are present in the mouth. So, it was necessary to modify oral and dental hygiene. With this change, the number of cases declined considerably. Furthermore, in the pre-antibiotic era, only one type of bacteria was responsible for causing lung abscesses, though now, polymicrobial flora has come into action.

Divisions of Lung Abscess:

After having a glance at history, let’s come to the main topic. Now, let’s understand the division of lung abscesses. 

Lung abscesses can be divided into several categories depending on factors like duration, etiology, and method of spreading. 

Here is the division of lung abscesses according to duration, etiology, and spreading method.


  • Acute (if the infection is of less than six weeks).
  • Chronic (if the infection exceeds six weeks.)


  • Primary (oropharyngeal secretions breathing, immunodeficiency, necrotizing pneumonia)
  • Secondary (haematogenic dissemination, bronchial obstructions, direct spreading from infection of mediastinum, subphrenic, and lung diseases that co-exist)

Method of spreading:

  • Brochogenic- refers to anything related to bronchi (oropharyngeal secretions aspiration, obstructions in bronchi as a result of tumor, foreign particles, swollen lymph nodes, congenital malformation)
  • Haematogenic- refers to anything related to blood (sepsis in the abdomen, infective endocarditis, thromboembolism sepsis). 

Acute lung abscess starts with not-so-well-defined gatherings around lung tissues filled with necrotic detritus. Moreover, in the center of the lung cavity is a mixture of necrotic tissues, necrotic granulocytes, and bacteria. These are surrounded by granulocytes (neutrophils) along with blood vessels and edema, ready to fight the disease. 

Chronic lung abscess starts with irregularly shaped, well-defined surroundings around the lung’s parenchyma. Moreover, Greyish lines and thick detritus fill the cavity. Pus is located at the center of the abscess with the presence or absence of bacteria. Finally, surrounded by a pyogenic membrane, through which leucocytes can cross to reach the infected area. The lymphocytes, histiocytes, and plasma cells, grouped as connective tissues, are present around the pyogenic membrane.

What are other Lung Diseases that co-exist?

Apart from having complications from the abscess, certain other diseases can co-exist with the ongoing infection like: 

  • Cystic fibrosis.
  • Bronchiectasis.
  • Obstruction in the Bronchial pathway due to tumor, foreign microbes, or swollen lymph nodes.
  • Bullous emphysema.
  • Malformations caused during pregnancy (vasculitis, cystitis).
  • infected pulmonary infarcts.
  • Broncho-oesophageal fistula.

Lung Abscess Causes:

The most common cause of lung abscess is the bacteria present in the mouth. These travel down the air passage due to aspiration and reach the target tissue, where it starts infecting.  So, periodontal diseases (gum diseases) are the chief factors causing lung abscesses. 

Now, the question might arise the body has a way to prevent bacteria from entering air passage, i.e., through coughing. So, how do bacteria reach the air passage despite this strong barrier?

The answer to this is simple; it is an unconscious action. A person is unaware of the aspiration that leads bacteria to the lungs. Despite unusual, it is the result of certain medications, drug use, sedation, anesthesia, etc. These conditions lend a person unconscious or drowsy and are thus unable to cough the bacteria caught in mucus. 

Another common cause of the infection is obstructed airways. If a bronchial passage is blocked, the mucus gathers around the obstruction. It provides easy transportation for bacteria, as the mucus cannot be coughed back due to obstruction.  

Immunodeficiency can cause the gathering of microbes not commonly found in the mouth. Certain fungi and bacteria may habituate your mouth, which causes even severe infections.

What are some contributing factors for lung abscesses? 

Apart from the causes mentioned above, certain other factors contribute significantly to the disease. These are:  

  • Age factor.
  • Periodontal infections.
  • Alcohol.
  • Neuromuscular disorders.
  • Malnutrition.
  • Corticosteroids therapy.
  • Immunosuppressants.
  • Mental retardation.

Lung Abscess Symptoms:

Early lung abscess symptoms are usually slow and like pneumonia symptoms. Some of the symptoms include:

  • loss in appetite.
  • fatigue and dizziness.
  • cough.
  • chest pain, especially while breathing.
  • night sweats.
  • loss in weight.
  • coughing with sputum often stained with blood.

The sputum often smells foul as bacteria in the mouth produce a foul smell. The patient might have bad breath and chest pain while breathing. Timely diagnosis is the key to curing abscession as delays might prove fatal. Moreover, if the infection is the result of Staphylococcus aureus or MRSA, the infection may be life-threatening. The patient may die within hours after infection.

Lung Abscess Diagnosis:

There are two typical diagnostic methods for lung abscess: 

  • Chest X-Ray: shows a clear chest image for detecting cavities and obstructions. 
  • CT scan: used sometimes when X-Rays cannot reveal the true cause. Sometimes, X-Ray results show other symptoms like cancer which resembles an abscess. 

Sometimes, bronchoscopy is the suggested diagnostic method. Bronchoscopy is the use of a bronchoscope, a thin tube with camera and light attached to view organs. 

It is due to several reasons: 

  • Antibiotics are not helping manage the condition.
  • Airpassage obstruction is detected.
  • Impaired immune system.

Lung Abscess Treatment:

If minor symptoms appear, seek medical advice as soon as possible. Continued delays might prove fatal. The physician will diagnose the condition and prescribe a suitable therapy option.  

Lung abscess treatment requires three main courses of action:

  • Antibiotics: initially, infected people get antibiotics intravenously (around 3-8 weeks). After an improvement in the condition, then switching to oral medication is recommended. Occasionally, physicians prescribe a combination of antibiotics for treatment purposes. You will have to take antibiotics until a clear X-Ray report shows up. 
  • Draining the abscess: At certain times, the lung abscess exceeds 6 cm in diameter; this calls for a drainage technique. The physician inserts the drain through nose or chest wall, and a CT scan assists in this process.
  • Surgical removal: it is a rare treatment method. Sometimes, the only solution left is the surgical removal of the abscess. Surprisingly, It was the most common therapy in the pre-antibiotic era.  Surgery removes infected parts, or sometimes an entire lung needs surgical removal to cure the disease.

Lung Abscess Complications:

Certain complications associated with lung abscesses include: 

  • A chronic abscess-this is the principal characteristic of this disease, especially; if it occurs for more than six weeks.
  • Empyema-the space between the lungs and chest wall is intruded by the abscess, which fills the space with pus. 
  • Bleeding-although bleeding comes in cough, sometimes heavy bleeding is also noted.


To conclude, a lung abscess is a complication in lungs caused due to microbial infections. The presence of abscess for more than six weeks confirms the presence of a lung abscession. Bacteria present in the mouth are the most common cause of lung abscess. Though spitting removes mucus-entrapped bacteria, it’s not true every time. Unconsciousness or drowsiness might help bacteria find their way to target tissue and start the infection cycle. The most common symptoms include fatigue, night sweats, weight loss, etc. There are two important diagnostic methods: X-Ray and CT scan. Both are viable for examining lung cavities. The most common treatment method includes prescribing antibiotics. If not effective, drainage or surgical removal might be effective. But the best way is to see a physician; as soon as, you feel the symptoms. A timely cure is the best cure!



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