Chapter 316 - Disorders of the Pleura

Question 1

How is the pleura fluid formed and drained? Thus, pathophysiologically, how does one explain pleural effusion?

Answer 1

“Normally, fluid enters the pleural space from the capillaries in the perietal pleura and is removed via the lymphatics in the perietal pleura. Fluid also can enter the pleural space from the intersticial spaces of the lung via the visceral pleura or from the peritoneal cavitiy via small holes in the diaphragm. The lymphatics have the capacity to absorb 20 times more fluid than is formed normally. Accordingly, a pleural effusion may develop when there is excess pleural fluid formation (from the intersticial spaces of the lung, the perietal pleura, or theperitoneal cavity) or when there is decreased fluid removal from the lymphatics.”

Question 2

How does one dianosis imagiologically a small pleural effusion?

Answer 2

Ultrassonography or lateral decubitus x-ray aswell as CT scan.

Question 3

Transudative pleural effusions are due to systemic factors, while exsudative pleural effusions are due to local factors.
True or False?

Answer 3

True.

Question 4

What are the main causes of transudative pleural effusion in the United States?

Answer 4

Left ventricular failure and cirrhosis.

Question 5

What are the criteria for exsudade pleural effusion?

Answer 5

At least one of the following:

• Pleural fluid protein/serum protein >0,5
• Pleural fluid LDH/serum LDH >0,6
• Pleural fluid LDH more than two-thirds the normal upper limit for serum

Question 6

Using Light’s criteria what is the percentage of transudades misidentified as exsudades?

Answer 6

~25%

Question 7

What is the cutoff value for the difference between protein levels in the serum and pleural fluid that is indicative of transudate, ragardless of Lights’s criteria?

Answer 7

> 3,1g/dL is almost always indicative of transudative pleural effusion.

Question 8

When does one perform a thoracentesis in a patient with heart failure and pleural effusion?

Answer 8

“In pacients with heart failure, a diagnostic thoracentesis should be performed if the effusions are not bilateral and comparable in size, if the patient is febrile, or if the patient has pleuritic chest pain to verify that the patient has a transudative effusion. Otherwise the patient’s heart failure is treat. If the effusion persists despite therapy, a diagnostic thoracentesis should be performed.”

Question 9

What is the cutoff value for NT-proBNP in pleural effusion indicative of congestive heart failure?

Answer 9

> 1500pg/mL

Question 10

How frequent is pleural effusion in patients with cirrhosis and ascitis?

Answer 10

~5%

Question 11

What is the most frequent cause of transudades and exsudades in the United States.

Answer 11

Heart failure and probably bacterial pneumonia, respectively.

Question 12

Name the main differences in the natural history of an aerobic vs anaerobic bacterial pneumonia.

Answer 12

“Patients with aerobic bacterial pneumonia and pleural effusion presente with an acute febril illness consistint of chest pain, sputum production, and leukocytosis. Patients with anaerobic infectionts present with a subacute illness with weight loss, a brisk leukocytosis, mild anemia, and a history of some factor that predisposes them to aspiration.”

Question 13

Name the factors, in order of increasing importance, indicative for invasive procedures regarding a pleural effusion.

Answer 13

“1. Loculated pleural fluid; 2. Pleural fluid pH less than 7,20; 3. Pleural fluid glucose less than 60mg/dL; 4. Positive Gram stain or culture of the pleural fluid; 5. Presence of gross pus in the pleural space.”

Question 14

What procedures are available for breakdown of adhesions?

Answer 14

Instilling the combination of a fibrinolytic agente, such as tissue plasminogen activator (10mg) and deoxyribonuclease (5mg) or performing a thoracoscopy.
“Decortication should be considered when these measures are ineffective.”

Question 15

Which tumors account for ~75% of exsudative pleural effusion?

Answer 15

Lung carcinoma, breast carcinoma and lymphoma.

Question 16

What is the main risk factor for mesothelioma?

Answer 16

Asbestos exposure.

Question 17

What is the dosage for doxycycline as sclerosing agente?

Answer 17

500mg

Question 18

How do you explain pleural involvement in primary tuberculosis (TB)?

Answer 18

“Tuberculouspleural effusions usually are assocaited with primary TB and are thought to be due primarily to a hypersensitivity reaction to tuberculous protein in the pleural space.”

Question 19

What are the cutoff values for adenosine deaminase and interferon-gamma that are indicative of pleural tuberculosis?

Answer 19

> 40UI/L and >140pg/mL, respectively.

Question 20

Chylothorax might be a consequence of trauma aswell as mediastinal neoplastic processes.
True or False?

Answer 20

True.

Question 21

In the lack of obvious thoracic trauma, how would you investigate a patient with chylothorax?

Answer 21

Lynphangiogram and mediastinal CT scan to assess the mediastinum for lymph nodes.

Question 22

What is the laboratorial characteristic of chylothorax?

Answer 22

Elevation of tiglyceride levels (>110mg/dL).

Question 23

Why is that one should not perform prolonged drainage of chylothoraxes?

Answer 23

“Patients with chylothoraxes should not undergo prolonged tube thoracostomy with chest tube drainage because this will lead to malnutrition and immunologic incompetence.”

Question 24

Name one criteria that may indicate the need for thoracoscopy or thoracotomy on a patient with hemothorax.

Answer 24

Pleural hemorrhage exceeding 200mL/h.

Question 25

Name three gynecological causes for pleural effusion.

Answer 25

Meigs’s syndrome.
Ovarian Hyperstimulation syndrome.
Pleural endometriosis.

Question 26

What is the difference between early and late pleural effusions related to coronary artery bypass surgery?

Answer 26

“Effusions occuring withint the first weeks are typically left-sided and bloody, with large numbers of eosinophils, and respond to one or two therapeutic thoracenteses. Effusions ocurring after the first few weeks are typically left-sided and clear yellow, with predominantly small lymphocytes, and tend to recur.”

Question 27

What characterizes a tension pneumothorax?

Answer 27

“A tension pneumothorax is a pneumothorax in which the pressure in the pleural space is positive throughout the respiratory cycle.”

Question 28

What is the main risk for primary spontaneous pneumothorax?

Answer 28

Cigarette smoking.

Question 29

How many patients have recurrent primary spontaneous pneumothorax?

Answer 29

About one-half.

Question 30

What techcnic is almost 100% successful in preventing pneumothorax recorrences?

Answer 30

Pleural abrasion either through thoracoscopy or thoracotomy.

Question 31

Why is a pneumothorax more dangerous in a patient with underlying pulmonary disease?

Answer 31

“Pneumothorax in patients with lung disease is more life-threatening than it is in normal individuals because of the lack of pulmonary reserve in these patients.”

Question 32

How does one treat a traumatic hemopneumothorax?

Answer 32

“one chest tube should be placed in the superior part of the hemithorax to evacuate the air and another should be placed in the inferior part of the hemithorax to remove the blood.”

Question 33

Which situations are usually associated with tension pneumothorax? Why is it life-threatening?

Answer 33

“This condition usually occurs during mechanical ventilation or resuscitative efforts. The positive pleural pressure is life-threatening both because ventilation is severely compromised and because the positive pressure is transmited to the mediastinum, resulting in decreased venous return to the heart and reduced cardiac output.”

Question 34

Which conditions are associated with each of the following findings in pleural effusions: (a) elevated amylase level; (b) elevated adenosine deaminase and/or interferon gamma; (c) eosinophils; (d) hematocrit of the pleural effusion >1/2 of the plasmatic hematocrit.

Answer 34

(a) esophageal rupture or pancreatic disease
(b) tuberculosis
(c) drug-induced pleural effusion
(d) hemothorax (mainly traumatic cause)