What Is Post-Obstructive Pneumonia?

Post-obstructive pneumonia is an infection in the lung that occurs due to a blockage in one of the airways. Behind this blockage, the mucus and fluids in the lung become trapped, leading to the infection.

Nearly all of these obstructions are caused by lung cancer, but a small percentage are not.

This article will discuss the symptoms, diagnosis, and treatment of post-obstructive pneumonia. 

Post-Obstructive Pneumonia Symptoms

The symptoms of post-obstructive pneumonia are similar to the symptoms of typical pneumonia, which are:

• Fever
• Cough
• Shortness of breath

There can be other, nontraditional symptoms with post-obstructive pneumonia that may not occur with a typical pneumonia. These can include:

• Poor appetite
• Weight loss
• Coughing up blood (hemoptysis)
• Chest pain
• Wheezing

Causes

In healthy lungs, air is breathed in through the nose and mouth and then travels down into the lungs through a windpipe called the trachea. After moving through the trachea, air moves into smaller windpipes, called the bronchial tubes. Air then moves down deeper into the lungs into smaller tubes called bronchioles. The bronchioles then transition into the air sacs called alveoli.

It is in the alveoli where gas exchange happens. During gas exchange, the oxygen breathed in is distributed into the bloodstream, and carbon dioxide is removed to be breathed out. 

The lungs normally have a thin layer of mucus lining the airways. This mucus can trap anything that shouldn’t be in the lungs, such as dust or bacteria. The mucus is then moved up and out of the lungs by coughing, clearing the throat, or sneezing.

In the instance of post-obstructive pneumonia, one of these airways becomes blocked, most often by a tumor. The airways can become blocked at any point along their path. They can be blocked through abnormal cells developing inside the airway, or by a tumor growing outside of or around the airway, which then puts pressure on the airway, closing it off.  

It has been estimated that 98% of post-obstructive pneumonia cases are caused by cancer.

After these airways become blocked, the mucus normally lining the airways becomes trapped. This mucus contains bacteria normally found in the mouth and airway tracts. It is possible for these bacteria to grow after becoming trapped in the airway.

However, not all post-obstructive pneumonias are caused by bacteria, and it can be difficult to determine what organism is the cause.

Diagnosis

As with other types of pneumonia, diagnosis of post-obstructive pneumonia begins with a physical exam. When someone develops symptoms such as cough and fever, they should be evaluated by a healthcare provider.

The healthcare provider will assess a patient's condition to determine the cause of symptoms. Based on the symptoms and examination alone, the doctor may feel a course of antibiotics is needed. In patients with post-obstructive pneumonia, a single short course of antibiotics will not fully treat the infection. If symptoms persist, you will need to return for a follow-up visit to your healthcare provider.  

When antibiotics do not treat the infection, further imaging tests, such as a chest X-ray or a computed tomography (CT) scan, may be ordered to get a picture of the lungs for better evaluation. 

Other diagnostic studies can include a bronchoscopy or an endobronchial ultrasound. During these exams, a long thin tube with a light and camera at the end is inserted into the airway. The scope is passed down into the smaller airways of the lungs to look for blockages or abnormalities. During these procedures, biopsies (tissue samples to be examined in a lab) can be taken of any suspicious areas, and fluid samples can be obtained to document any source of infection.

Treatment

The first treatment for post-obstructive pneumonia is often antibiotics, usually lasting for multiple weeks. The acute infection must be treated and resolved before your healthcare team will proceed with further treatments.

However, once the infection has been resolved, procedures to try to remove some of the tumor tissue blocking the airway may be needed.

These procedures can include surgery, radiation, laser therapy, or stent placement. 

Surgery

During surgery, the affected part of the lung is removed. However, this is often only needed when there is a possibility of curing the underlying cancer, not in cases in which cancer is widespread.

Radiation

External beam radiation may be used for some people who may not be a good candidate for more invasive procedures. During radiation, high-energy X-ray beams are directed at the tumor tissue. This can shrink the tumor and allow the airway to open again.

Laser Bronchoscopy

During a laser bronchoscopy, a tube is inserted into the airway to the level of blockage. A laser is then used to burn the tissue that is blocking the airway and allow it to open.

Stent placement

If an airway is being closed off from a tumor surrounding the outside of the airway, a stent may need to be placed. A stent is usually made out of silicone or metal and is placed inside the area being compressed. The stent gives support to the airway from the inside, holding it open from the force being pushed from the outside. This can allow the airway to open again.

Prognosis 

Post-obstructive pneumonia is a serious problem and can be life-threatening. It can lead to many complications, which can include:

• Abscess in the lung (pus-filled cavity)
• Fistula formation (abnormal connection between an abscess and part of the body)
• Recurrent infection
• Antibiotic resistance

The prognosis of treating post-obstructive pneumonia depends on many factors, such as the type of cancer that is causing the blockage, the overall health of the person who has it, and how they respond to treatment.

A Word From Verywell 

Having post-obstructive pneumonia or knowing someone who does can be a stressful and scary time. It is important to follow all instructions from the healthcare provider who is treating it.

Be sure to complete all of the medications that are prescribed and discuss any concerns you have with your healthcare team. Report any worsening symptoms immediately. If you smoke cigarettes or use other tobacco products, quitting these products is helpful.