Parapneumonic Pleural Effusions and Empyema Thoracis - Causes and Treatment

Introduction:

An accumulation of the exudative pleural fluid in the pleural cavity caused due to pneumonia is referred to as parapneumonic pleural effusion. This condition is mostly caused by bacterial infections. Patients with pneumonia are commonly associated with pleural effusion. People infected with bacterial pneumonia report about 40 to 60 % are associated with pleural effusion with varying severity. Pleural effusion refers to fluid collection in the pleural cavity (a thin space between the lung and the chest cavity). Normally, a slight quantity of fluid is present within the pleural space. An increased accumulation of fluid in the pleural space due to an infection prevents the lungs from expanding and may result in difficulty breathing.

What Are the Types of Parapneumonic Effusion?

Parapneumonic effusion is classified into three types depending on the type of fluid present in the pleural space and the mode of treatment. The types of parapneumonic pleural effusions include-

• Uncomplicated Parapneumonic Effusion: There are no signs of bacteria in the fluid. The pleural fluid is clear or cloudy. With the administration of antibiotics, the condition of pneumonia improves.

• Complicated Parapneumonic Effusion: The nature of the pleural fluid is cloudy. The bacteria enter the lungs into the pleural space and cause the accumulation of fluid and white blood cells. This condition is managed by draining the fluid.

• Empyema Thoracic: The fluid accumulated in the pleural cavity is thick and present with whitish-yellow pus. It occurs if pneumonia is left untreated.

What Is the Difference Between Parapneumonic Pleural Effusion and Empyema?

• Parapneumonic pleural effusion refers to the fluid build-up in the pleural cavity, whereas empyema thoracis refers to the accumulation of pus with a thick yellow-whitish fluid comprising bacteria and dead white blood cells caused due to pneumonia.

• The empyema condition is the progression of parapneumonic effusion. If pneumonia is not treated in time, it may lead to empyema. About five to ten percent of parapneumonic pleural effusion cases may develop into empyema.

What Are the Symptoms of Parapneumonic Pleural Effusion?

The common symptoms of parapneumonic pleural effusion may include the following-

• Shortness of breath.

• Cough (phlegm sometimes).

• Fever.

• Fatigue.

• Pain in the chest.

What Are the Causes of Parapneumonic Pleural Effusion?

• Viral and bacterial pneumonia is responsible for causing parapneumonic effusion but is most commonly caused by bacteria.

• Elderly people and children are the most susceptible among other groups to parapneumonic pleural effusion from pneumonia.

• In the case of infection, the immune system releases white blood cells, which invade against the bacteria or virus.

• The white blood cells damage the small blood vessels in the lungs and cause fluid to leak out into the pleural space.

• If parapneumonic pleural effusion is not treated promptly, the dead white blood cells and bacteria get collected in the fluid and can result in empyema.

What Is Empyema?

• Empyema thoracis is otherwise known as purulent pleuritis or pyothorax.

• It refers to the accumulation of pus in the pleural space, consisting of dead cells, leucocytes (white blood cells), and micro-organisms like bacteria.

What Are the Causes of Empyema Thoracis?

• This condition is the progression of pneumonia.

• Pneumonia is caused by bacteria which include Streptococcus pneumoniae and Staphylococcus aureus.

• Sometimes this may occur after surgery due to an infection transferred from the instruments.

What Are the Risk Factors of Empyema Thoracis?

• Pneumonia is the most significant risk factor.

• Chronic obstructive pulmonary disease.

• Rheumatoid arthritis (an autoimmune disease that affects various joints).

• Diabetes (a metabolic condition that causes raised blood sugar levels).

• Alcohol abuse.

• Surgery.

• Weak immune system.

• Lung abscess (a pus-filled cavity called an abscess in the lungs).

• Bronchiectasis (widening of lung airways leading to excess mucus build-up).

What Are the Symptoms of Empyema?

It is of two types which include simple and complex.

• Simple Empyema: Simple empyema is the early stage characterized by the presence of free-flowing pus. Some of the symptoms include-

• Dry cough.

• Fever.

• Shortness of breath.

• Pain in the chest when breathing.

• Sweating.

• Confusion.

• Headache.

• Complex Empyema: Complex empyema is characterized by severe inflammation, which may happen in the later stage of the illness. Fibrous or scar tissue is formed, dividing the chest cavity into small cavities called loculations. It may progress to include a thick peel over the pleura, called the pleural peel. The pleural peel formation prevents the lungs from expanding. Surgical procedures can manage this condition. Some of the symptoms include-

• Fast breathing.

• Rapid heart rate.

• Chills.

• Fever.

What Are the Treatment Approaches for Parapneumonic Pleural Effusion and Empyema Thoracic?

Early administration of antibiotic therapy to treat bacterial pneumonia can help in the prevention of parapneumonic pleural effusion and empyema thoracis.

• Management of Parapneumonic Pleural Effusion:

• If the antibiotic therapy fails or is not provided in time, the condition may progress to empyema.

• It is managed by draining the fluid from the pleural space. Two methods of draining are followed, which include thoracentesis.

• In this procedure, a small needle is inserted between two ribs on the side, and the fluid is removed from the pleural space.

• Another method is placing a chest tube or catheter in the chest to empty the fluid stocked up in the pleural space.

• In case of loculations inside the pleural fluid, intrapleural fibrinolytic may be given to break them and create a single pocket.

• Surgery is recommended if the draining procedure does not work out effectively. Various surgical procedures include-

1. Thoracoscopy- A few incisions are done in the chest to place the small camera and some instruments. This technique is used in the diagnosis of parapneumonic pleural effusion. It is also used in removing pleural fluid from the space.
2. Thoracotomy- Small incisions in the chest wall between the ribs (bony framework in the chest) are made, and the fluid is extracted.
3. Video-Assisted Thoracic Surgery (VATS)- Small incisions are created in the chest wall to set up a tiny camera and undersized instruments. The camera gives a clear picture inside the lungs, which assists in the removal of pleural fluid from the space.

Conclusion:

The prognosis relies on the severity of the condition and how early the treatment is provided. People with parapneumonic pleural effusion are in the state of severe or advanced pneumonia, which can even be life-threatening. Early treatment results in early recovery. During the follow-ups, chest X-rays and other tests are taken to check whether the infection is cleared completely.