Pleural etc

Question 1

Pleural effusion classification?

Answer 1

A pleural effusion is fluid in the pleural space. Effusions can be divided by their protein concentration into transudates (<25g/L) and exudates (>35g/L)

 if protein is 25–35g/L: If pleural fluid protein/serum protein >0.5, effusion is an exudate

Question 2

Blood in pleural space?

pus. .?
chyle. .?

blood and air..?

Answer 2

Blood in the pleural space is a haemothorax,

pus in the pleural space is an empyema, a

nd chyle (lymph with fat) is a chylothorax.

Both blood and air in the pleural space is called a haemopneumothorax.

Question 3

causes of transudates?

Answer 3

due to ↑venous pressure (cardiac failure, constrictive pericarditis, fluid overload),

or hypoproteinaemia (cirrhosis, nephrotic syndrome, malabsorption).

Also occur in hypothyroidism and Meigs’ syndrome (right pleural effusion and ovarian fibroma).

Question 4

causes of exudates?

Answer 4

mostly due to increased leakiness of pleural capillaries secondary to *infection, inflammation, or malignancy*.

Causes: pneumonia; TB; pulmonary infarction; rheumatoid arthritis; SLE; bronchogenic carcinoma; malignant metastases; lymphoma; mesothelioma; lymphangitis carcinomatosis.

Question 5

SIGNS OF pleural effusion

Answer 5

Decreased expansion; stony dull percussion note; diminished breath sounds occur on the affected side.

Tactile vocal fremitus and vocal resonance are ↓ (inconstant and unreliable).

Above the effusion, where lung is compressed, there may be bronchial breathing.

With large effusions there may be tracheal deviation away from the effusion.

Look for aspiration marks and signs of associated disease: malignancy (cachexia, clubbing, lymphadenopathy, radiation marks, mastectomy scar); stigmata of chronic liver disease; cardiac failure; hypothyroidism; rheumatoid arthritis; butterfly rash of sle.

Question 6

Typical clinical chemistry of the fluid in

Empyema, malignancy, TB, RA, SLE

(exudate)

Answer 6

Glucose <3.3mmol/L

pH <7.2

LDH↑ (pleural:serum >0.6)

Question 7

MANAGEMENT of pleural effusions

Answer 7

treating the underlying cause.

• Drainage: If the effusion is symptomatic, drain it, repeatedly if necessary. Fluid is best removed slowly (≤2L/24h). It may be aspirated in the same way as a diagnostic tap, or using an intercostal drain
  
  • Pleurodesis with tetracycline, bleomycin, or talc may be helpful for recurrent effusions. Thorascopic talc pleurodesis is most effective for malignant effusions. Empyemas are best drained using a chest drain, inserted under ultrasound or ct guidance.

Question 8

management of acute massive pleural effusion

Answer 8

• Give O2.

• IV access: via a wide-bore cannula or internal jugular central line. If central access is difficult then avoid attempting unless peripheral access is clearly inadequate. Attempt to cannulate (internal jugular veins only) on the normal side. A bilateral pulmonary problem will be a disaster.

• Take blood: for FBC, clotting, and urgent cross-match (6 units).

• Correct coagulopathies.

• Restore circulating volume: if BP low or tachycardic, then give a plasma expander 500mL stat, according to size of effusion drained and response.

• Insert a chest drain (The drain should be left unclamped and allowed to drain freely, the amount drained should be recorded

Question 9

Light’s criteria for pleural fluids:

Answer 9

•The pleural fluid is an exudate if one or more of the following criteria are met:

• Pleural fluid protein divided by serum protein >0.5
  
  • Pleural fluid LDH divided by serum LDH >0.6
  • Pleural fluid LDH more than two-thirds the upper limit of normal serum LDH level