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Pleurisy
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The pleura is a two-layered covering that surrounds the lungs. Pleurisy, also called pleuritis, is inflammation of the outer layer, the parietal pleura. It causes sharp chest pain in one specific spot that gets worse when you breathe, cough or sneeze.
Why does it hurt? Because the two layers are not the same. The inner layer, the visceral pleura, lies on the lung and has no pain receptors. The outer layer, the parietal pleura, lines the inside of the chest wall and does have somatic fibers, the nerve fibers that carry sensations such as pain. When it becomes inflamed, the substances released by the inflammation, called inflammatory mediators, trigger the pain.
Between the two layers there is fluid, the pleural fluid, which lets them glide over each other as you breathe. When they are inflamed they can rub together, and that rubbing can produce a sound loud enough to be heard, the pleural friction rub. It is described as sounding like shoes squeaking on a wet surface.
In brief
Pleurisy, or pleuritis, is inflammation of the parietal pleura, the outer layer of the lining of the lungs, causing sharp, localized chest pain that worsens with breathing, coughing or sneezing.
The visceral pleura, which covers the lung, has no pain receptors; the parietal pleura, which lines the chest wall, has somatic fibers, and inflammatory mediators trigger the pain.
Pleural fluid lets the layers glide; when inflamed, they can rub and create an audible pleural friction rub, like shoes squeaking on a wet surface.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingPleurisy, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated