What complications can arise from pleurisy? 

Pleurisy is an inflammation of the pleural membranes that line the lungs and chest wall, often causing sharp chest pain. While the inflammation itself frequently resolves without long-term issues, it can lead to various complications depending on the underlying cause and the severity of the inflammatory response. These complications can range from a buildup of fluid around the lungs to more serious infections within the chest cavity that require urgent medical intervention. 

What We’ll Discuss in This Article 

• The development of pleural effusion and its impact on breathing. 

• The risks of empyema, where fluid around the lung becomes infected. 

• Atelectasis and the risk of lung collapse due to shallow breathing. 

• The formation of pleural thickening and adhesions (scarring). 

• Pneumothorax as a potential complication of pleural injury. 

• Long-term respiratory effects of chronic pleural inflammation. 

Pleural Effusion 

One of the most frequent complications of pleurisy is pleural effusion, which occurs when excess fluid builds up in the small space between the two layers of the pleura. Inflammation causes the blood vessels in the pleura to become more permeable, allowing fluid to leak out and collect around the lung. While a small amount of fluid can actually act as a lubricant and temporarily reduce the sharp pain of pleurisy, a larger volume can be problematic. 

As the volume of fluid increases, it begins to compress the lung tissue, preventing it from expanding fully during inhalation. This leads to increased shortness of breath and a feeling of heaviness or pressure in the chest. In the UK, if a pleural effusion is significant enough to cause respiratory distress, a doctor may need to perform a procedure to drain the fluid for testing and symptom relief. You can find more information on pleural effusion and its management from the NHS. 

Empyema (Infected Fluid) 

In some cases, particularly when pleurisy is caused by bacterial pneumonia, the fluid that has collected in the pleural space can become infected. This serious complication is known as an empyema. Instead of a clear, sterile fluid, the pleural space becomes filled with pus, which is thick and difficult for the body to reabsorb naturally. 

An empyema is a medical emergency that usually requires hospital admission. Symptoms of an empyema include a persistent high fever, night sweats, weight loss, and an overall feeling of being very unwell. Treatment typically involves a combination of strong intravenous antibiotics and the insertion of a chest tube (a drain) to remove the infected material. If left untreated, an empyema can lead to permanent scarring and may require surgery to clear. 

Atelectasis and Lung Collapse 

Atelectasis is a complication that arises not from the infection itself, but from the body’s reaction to the sharp pain of pleurisy. Because it hurts to take a deep breath, many patients instinctively take very shallow, quick breaths a behaviour known as “guarding.” When the lungs do not expand fully, the small air sacs (alveoli) at the base of the lungs can deflate and collapse. 

This collapse of lung tissue reduces the surface area available for oxygen exchange, which can make a patient feel more breathless and fatigued. Furthermore, collapsed areas of the lung are more prone to trapping mucus and bacteria, which significantly increases the risk of developing secondary pneumonia. This is why effective pain relief and deep-breathing exercises are considered a vital part of pleurisy treatment. 

Pleural Thickening and Adhesions 

When the pleural membranes are inflamed for a prolonged period, the healing process can lead to the formation of scar tissue. This is known as pleural thickening. Over time, the normally thin, flexible membranes can become “stiff” and less able to slide smoothly. In some cases, the two layers of the pleura can even stick together, forming what are called “adhesions.” 

While minor thickening often causes no symptoms, more extensive scarring can restrict the movement of the chest wall and the expansion of the lungs. This may result in a permanent, slight reduction in lung function or a persistent dull ache in the chest. According to NICE clinical knowledge summaries, monitoring for these changes is particularly important in patients who have had recurrent bouts of pleurisy. 

Pneumothorax 

A pneumothorax, or collapsed lung, occurs when air leaks into the pleural space, putting pressure on the outside of the lung and causing it to deflate. While less common than effusion, a pneumothorax can occur if the pleurisy is associated with certain types of lung infections or if there is an underlying structural weakness in the lung tissue that is aggravated by the inflammation. 

The onset of a pneumothorax is usually sudden and causes an immediate increase in sharp chest pain and severe difficulty breathing. This is a serious complication that requires urgent imaging, such as a chest X-ray, and may require the insertion of a needle or chest drain to remove the trapped air and allow the lung to re-inflate. 

Conclusion 

The complications of pleurisy range from manageable fluid buildup to serious infections like empyema or structural issues like lung collapse. While most people recover from pleurisy without lasting damage, the risk of fluid accumulation and scarring makes medical monitoring essential. Effective pain management is also critical to prevent atelectasis and ensure the lungs remain fully expanded during the healing process. If you experience severe, sudden, or worsening symptoms, call 999 immediately. 

Authority Snapshot (E-E-A-T Block) 

This article is designed to provide educational information on the clinical complications associated with pleurisy. It is written and reviewed by Dr. Rebecca Fernandez, a UK-trained physician with experience in internal medicine and emergency care. All information is strictly aligned with the latest clinical standards provided by the NHS and NICE to ensure the highest level of accuracy for patients.