Pleural Disease

Question 1

What is Light’s criteria?

Answer 1

Light’s criteria allows one to classify a pleural effusion as exudative or transudative. Light’s criteria are the following:

1) Pleural fluid protein / serum protein > 0.5
2) Pleural fluid LDH / serum LDH > 0.6
3) Pleural fluid LDH greater than 2/3 the upper limit of normal

If a pleural fluid meets one of them criteria, then it is classified as exudative.

Question 2

What is pleurisy?

Answer 2

Pleurisy is inflammation of the visceral and parietal pleurae that surround the lungs and line the thoracic cavity. It may be primary or secondary; unilateral, bilateral, or local; acute or chronic, fibrinous, serofibrinous, or purulent. Common causes of pleurisy include viral infections, pneumonia, pulmonary embolism, rib fracture, and serositis from autoimmune disease.

Question 3

What is asbestosis?

Answer 3

Asbestosis is a pneumonoconiosis due to repeated orprolonged inhalation of asbestos particles, which penetrate bronchioles and alveolar walls resulting in diffuse scarring of the lung.

CausesL Cumulative exposure to asbestos dusts and fibers causes asbestosis. The greater the total exposure and the longer the duration, the greater the likelihood of developing lung disease.

Symptoms: Symptoms include shortness of breath with exercise or, when there is extensive fibrosis, dyspnea at rest. In advanced disease, the patient may complain of a dry cough (productive in smokers), chest pain (often pleuritic), and recurrent respiratory tract infections. Symptoms and signs of asbestosis usually take decades to develop. A characteristic physical finding in asbestosis is a crackling sound (rales) made when the patient breathes in and out. It is heard when a stethoscope is placed on the patient’s chest wall, and the patient breathes in and out.

Diagnosis: Asbestos exposure is evident on chest x-rays, chest CT scans, and other forms of imaging when plaques are seen in the pleura. When the diagnosis is uncertain, bronchoalveolar lavage or biopsies (endobronchial or open lung) can be used for definitive identification of mineral fibers. Progressive reductions in lung function can be identified by having the patient walk while wearing an oximeter on an earlobe or the finger, (to measure the oxygen content of the blood during a 6 minute walking test).

Prevention: Exposure to asbestos and other toxic dusts and fibers can be prevented by wearing well-fitting respirator masks during industrial activities, such as construction, manufacturing, and mining.