What is a lung abscess?

A lung abscess is a bacterial infection that occurs in the lung tissue. The infection causes tissue to die, and pus collects in that space. A lung abscess can be challenging to treat, and it can be life-threatening.

Lung abscesses can be classified as primary or secondary. They develop from different strains of bacteria and have different causes.

Primary abscesses are caused by an infection, pneumonia, within your lung. Aspiration pneumonia is an infection that develops after food or secretions from your mouth, stomach, or sinuses are inhaled into your lungs instead of going into your esophagus. It’s a very common cause of primary abscesses.

Aspiration of food or secretions occurs most often while someone is sedated or unconscious, either through intoxication or anesthesia. The inhaled material is often damaging to lung tissue. It’s also typically filled with bacteria, either from an infection or from normal bacteria found in the mouth, respiratory tract, or stomach.

The most common illness that makes a person susceptible to developing a lung abscess is alcoholism. Those who misuse alcohol often experience bouts of vomiting and altered levels of consciousness. These conditions increase the likelihood of inhaling stomach contents and bacteria into the lungs, which can cause an infection. People who misuse alcohol often have weakened immune systems due to poor overall health and nutrition, which also makes it easier to develop an infection.

Secondary abscesses are caused by anything other than an infection that starts in your lung. This can be an obstruction of the large airways in your lung, coexisting disease in your lungs, or infections from other parts of your body that spread to your lungs.

The most noticeable symptom of a lung abscess is a productive cough. The contents that are coughed up may be bloody or pus-like, with a foul odor.

Other symptoms include:

  • bad breath
  • fever of 101°F or higher
  • chest pain
  • shortness of breath
  • sweating or night sweats
  • weight loss
  • fatigue

People who have alcoholism or have recently been ill (especially with pneumonia) have a high risk of developing a lung abscess. Other people with weakened immune systems who have conditions such as cancer, HIV, organ transplants, and autoimmune disease are also at risk. The risk is high for people who have recently been under anesthesia or sedation and those who have been unconsciousness from injury or illness. Inhaling a foreign object that blocks a large airway is also a risk factor.

To diagnose a lung abscess, your doctor will first look at your health history. Your doctor will review recent operations where anesthesia was used. If an abscess is suspected, your doctor will analyze the sputum or pus. Your doctor might also use imaging tools, such as an X-ray or CT scan, to look at where the infection is in the lungs and rule out other conditions, such as cancer or emphysema. For more serious infections, your doctor might perform a procedure to take a sample from the abscess.

If your doctor thinks a foreign object has entered the lungs, he or she might insert an instrument called a bronchoscope into the windpipe to locate it.

The primary treatment for a lung abscess is antibiotics. Long-term use of medication might be necessary for up to six months. Lifestyle changes such as not smoking and drinking more fluids may also be suggested.

In some cases, more invasive procedures or surgery may be necessary. A tube can be inserted into the lungs to drain pus from the abscess, or a surgical procedure may be required to remove infected or damaged lung tissue.

In rare cases, a lung abscess can rupture. This is a serious medical concern. Potential complications following rupture or surgical treatment of an abscess are:

  • Empyema. This is a large collection of infected fluid around the lung that occurs where the abscess is. It can be life-threatening and requires immediate medical attention so it can be removed.
  • Bronchopleural fistula. This is when a connection develops between a large airway inside your lung and the space in the lining around the outside of your lung. It’s corrected through a scope or surgery.
  • Bleeding from your lung or chest wall. This can be a small amount of blood or a lot of blood, which is life-threatening.
  • Infection spreading to other parts of the body. If the infection leaves your lung, it can then produce abscesses in other parts of your body including your brain.

A lung abscess treated with antibiotics heals without complications about 90 percent of the time. People with suppressed immune systems, underlying health conditions, or without access to healthcare are more susceptible to adverse outcomes.