Dry pleurisy (pleural syndrome proper)
Dry pleurisy is based on intense irritation of the nerve endings, with which the pleura is richly supplied. This symptom complex has clearly defined causes and a vivid clinical presentation.
Syndrome etiology includes three main groups of factors:
- Direct pleural damage: various inflammatory processes (pleurisy), chest trauma, tuberculosis, as well as tumors and their metastases.
- Irritation by pathological contents: the reaction of the layers to the presence of exudate, transudate, pus, blood, or air in the cavity.
- Reactive inflammation: occurs as a secondary response to pathological subpleural foci located in the lung parenchyma itself, in direct proximity to the pleura.
Clinical presentation in pleural layer involvement
The initial manifestations of the syndrome are always associated with marked discomfort and reflex reactions of the body.
Main symptoms and inspection findings:
- Pain syndrome. Pain on the affected side is pronounced. It occurs due to the mechanical friction of inflamed, rough pleural layers against each other during breathing.
- Forced position. To minimize pain, the patient tries to limit the movement (excursion) of the chest on the affected side. Most often, the patient lies on the affected side or sits with a noticeable lean toward the affected side.
- Lagging in the act of breathing. Visual inspection clearly reveals lagging of the affected half of the chest, which is a consequence of reflex guarding due to intense pain.
Interesting dynamic feature: as soon as fluid (effusion) begins to accumulate in the pleural cavity, the pleural layers physically separate. Friction ceases, and the pain syndrome completely disappears.
Physical examination findings: palpation and auscultation
During objective examination of a patient with dry pleurisy, the key sign is the pleural friction rub.
- Sound characteristics: rough, exceeding normal vesicular breath sounds in volume.
- Respiratory phases: unlike some other auscultatory phenomena, the pleural friction rub is heard in both phases of the respiratory cycle — during both inspiration and expiration.
- Palpatory detection: in some cases, the inflammation is so pronounced and the friction rub is so rough that it can even be detected by palpation, simply by placing the palm on the chest.
Fluid accumulation syndrome (Hydrothorax)
When fluid accumulates in the pleural cavity, the physical examination findings change cardinally. To verify the diagnosis and substantially refine percussion and auscultation data, radiological examination is mandatory.
Percussion signs: The configuration of the upper border of the dullness zone depends on the nature of the fluid. If transudate accumulates, this border lies closer to a horizontal line. In the case of exudate, an oblique line of dullness is formed (Ellis-Damoiseau line).
Auscultatory picture in effusion:
- Directly over the dullness zone: vesicular breath sounds are sharply diminished or, most often, completely absent, as the fluid dampens the sound waves.
- Above the dullness zone: diminished vesicular breath sounds are determined.
Briefly: answers to topical questions
What percussion triangles are determined on the posterior surface of the chest in exudative pleurisy?
In exudative pleurisy, two percussion triangles are determined on the posterior surface of the chest.
- Garland's triangle — located on the affected side (above the fluid level). Characterized by a dull-tympanic sound due to the compressed lung.
- Rauchfuss-Grocco triangle — located on the healthy side, adjacent to the spine in the lower part. Characterized by dullness of the sound due to displacement of the mediastinal organs toward the healthy side.
By what clinical and auscultatory signs is the pleural friction rub differentiated from crepitation?
According to its sources, the pleural friction rub is characterized by the following signs:
- it is associated with pleurisy and accompanied by pronounced pain on the affected side;
- the patient may assume a forced position that limits chest movement on the affected side;
- inspection reveals lagging of the affected half of the chest in the act of breathing;
- on auscultation, the pleural friction rub is rough, louder than vesicular breathing, and heard in both phases of respiration — inspiration and expiration;
- sometimes it is so rough that it is detected by palpation.
The cough test does not differentiate pleural friction rub from crepitation: by source, both crepitation and pleural friction rub remain unchanged after coughing. This test is used to distinguish them from rales.
What laboratory tests and biochemical criteria are used for the differential diagnosis of transudate and exudate?
The following criteria are used for the differential diagnosis of transudate and exudate:
| Sign | Exudate | Transudate |
|---|---|---|
| Specific gravity | > 1.015; in classical textbooks — higher than 1.018 | Lower, as a rule lower than 1.015–1.018 |
| Protein content | > 2,5% | Lower than in exudate |
| Ratio of pleural fluid protein to blood plasma protein | A ratio > 0.5 indicates exudate | Indicated in the source as a criterion for exudate at a value > 0.5 |
| Rivalta test | Positive: a "cloud" forms | Negative |
| Coagulability | May clot at high fibrin content | Does not clot spontaneously |
| Appearance | More often turbid due to cellular elements | Clear |
The "patient protects the affected side" rule: in dry pleurisy, the patient lies specifically on the affected side to "press down" on it with body weight, limit lung excursion, and thereby reduce the excruciating pain from the friction of the inflamed pleural sheets.
Class and exam questions
Why does pain suddenly disappear in pleurisy even though the patient has not recovered?
This occurs when dry pleurisy transitions into exudative pleurisy. The accumulated fluid (effusion) separates the inflamed pleural sheets, they stop rubbing against each other, and the mechanical irritation of pain receptors ceases.
During which phase of respiration is a pleural friction rub heard?
Pleural friction rub is heard continuously: it is present during both inspiration and expiration.
How to differentiate transudate from exudate using percussion?
When transudate accumulates, the upper boundary of percussion sound dullness lies almost horizontally, whereas exudate is characterized by an oblique upper boundary.
What else to study on this topic
- Topographic zones and triangles in exudative pleurisy
- Features of the Ellis-Damoiseau line and the mechanism of its formation
- Mechanisms of transudate and exudate formation in the pleural cavity
- Radiological signs of fluid and gas accumulation
- Pathogenesis of reactive inflammation in subpleural lesions of the lung parenchyma
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