Effusions & Pneumothorax

Question 1

When can you forgo thoracentesis for parapneumonic effusions?

Answer 1

Can forgo sampling if < 1 cm on lateral decubitus.

Question 2

What is Light’s criteria?

Answer 2

Pleural fluid is an exudate if one or more of the following criteria are met:

(1) Pleural fluid protein/serum protein > 0.5
(2) Pleural fluid LDH/serum LDH 0.6
(3) Pleural fluid LDH > 2/3 ULN for serum LDH

Question 3

What is Meig’s syndrome?

Answer 3

Triad of benign ovarian tumour w/ascites and pleural effusion.

Question 4

What rules out an educative pleural effusion?

Answer 4

When all Light’s criteria is absent (- LR 0.04)

Question 5

What are the most common causes of chylothorax?

Answer 5

1 - Malignancy (most commonly lymphoma)

Otherwise, trauma/surgery, TB and LAM

Question 6

What causes of pleural fluid eosinophilia (>10%)?

Answer 6

Asbestos related (BAPE)
Drugs (Nitrofurantoin) 
Malignancy (Lung)
Infection (Parasites)
PE
EGPA

Question 7

What causes profoundly low pleural glucose levels (< 1 mmol)?

Answer 7

RA
Empyema

Otherwise, TB, malignancy and SLE cause low glucose, typically in the 1-3 range.

Question 8

What are the most common causes of lymphocytosis in the pleural fluid?

Answer 8

Most are either TB or lymphoma.

Otherwise, the differential diagnosis includes other cancers (carcinoma), yellow nail, sarcoidosis and RA.

Question 9

What are the indications for a chest drain in parapneumonic effusions?

Answer 9

(1) Drainage of frank pus/cloudy.
(2) Positive Gram Stain or Culture
(3) pH < 7.2 (or glucose < 3.4)
(4) > 50% of hemithorax or loculations on imaging

Question 10

What is the size cutoff for monitoring versus intervention for PNX?

Answer 10

Small < 2 cm with minimal signs and symptoms can be monitored.

Question 11

What are the risk factors for primary PNX?

Answer 11

Risk Factors - smoking, family hx, Marfan syndrome, thoracic endometriosis

Question 12

What is the most common cause of secondary spontaneous PNX?

Answer 12

COPD