In pleurisy, fluid flooding the chest can actually ease the pain
The lungs normally slide inside two thin, smooth membranes. In pleurisy those layers become inflamed and grate against each other with every breath, producing a stabbing pain and a scratchy noise a stethoscope can pick up. Oddly, when fluid collects between them the pain may fade, though breathing then gets harder.
The membranes in question, the pleurae, wrap the lungs and line the inside of the chest wall. When they are inflamed, the typical complaint is a sudden sharp or burning pain on one side of the chest that worsens with deep breaths, coughing, sneezing or laughter, sometimes spreading to the shoulder or back. Hippocrates described the condition around 400 BC, and roughly a million Americans are affected each year.
Viral infections are the most frequent trigger, including influenza, adenovirus and COVID-19. The list of other culprits is long: bacterial pneumonia and tuberculosis, lupus and rheumatoid arthritis, blood clots in the lungs, heart surgery, pancreatitis, asbestosis and lung cancer among them. In some people no cause is ever found. Because a heart attack, pericarditis or a collapsed lung can feel similar, doctors look for the underlying disorder rather than treating the pain in isolation.
Several complications involve the pleural space. A pleural effusion is excess fluid that pushes the two layers apart, which is why the rubbing and pain can ease; a large amount, however, can collapse the lung. Infected fluid can turn into an abscess called an empyema. Air in the space is a pneumothorax, and blood is a hemothorax, which can press on the lung and even cause shock.
Diagnosis starts with listening for the friction rub, then may add a chest X-ray, sometimes taken with the patient lying on the painful side to show fluid shifting, blood tests, an ECG, ultrasound, CT or MRI. Ultrasound can locate fluid but cannot image the lungs themselves, because air scatters sound waves. If fluid is present, a needle procedure called thoracentesis draws a sample. Treatment depends on the cause, with painkillers such as ibuprofen and breathing exercises sometimes used alongside.
Source: Pleurisy
