Pulmonary System

Question 1

What are the (3) broad causes of a pleural effusion?

Answer 1

1. Increased drainage of fluid into pleural space
2. Increased production of fluid by cells in the pleural space
3. Decreased drainage of fluid from pleural space

Question 2

What are the (2) types of effusions and their causes?

Answer 2

• Transudative: elevated capillary pressure in visceral/parenteral pleura (CHF), decreased plasma oncotic pressure (hypoalbuminemia)
• Exudative: increased permeability of pleural surfaces, decreased lymphatic flow from pleural surface due to damage to membranes/vasculature

Question 3

What tests are indicated when an exudative effusion is suspected? What is criteria is used to determine exudative vs transudative?

Answer 3

Tests: CBC, Total protein, LDH, glucose, pH, amylase, TG, microbiology, cytology
Lights criteria
- Protein (pleural:serum) >0.5
- LDH (pleural:serum) >0.6 OR pleural >2/3 upper limit of normal serum

Question 4

What are common causes of pleural effusions?

Answer 4

CHF
Pneumonia
Malignancies: lunge > breast > lymphoma
PE
Viral disease
Cirrhosis with ascites ("hepatic hydrothorax")

Question 5

What are the clinical signs and symptoms of a pleural effusion?

Answer 5

Symptoms
- usually asx
- dyspnea on exertion
-peripheral edema
- orthopnea, paroxysmal nocturnal dyspnea
Signs
- dullness to percussion
- decreased breath sounds over effusion
- decreased tactile fremitus

Question 6

What are the diagnostic tools for a pleural effusion and what would they show?

Answer 6

CXR
- blunting of costophrenic angle
- can only detect effusions >250 mL
- lateral can determine smaller ones + free vs loculated
CT chest
- more reliable
Thoracentesis
- 75% sensitivity + important clinical information
- therapeutic drainage
- CI if effusions <10mm thick on lateral decubitis CXR

Question 7

What are the treatments for pleural effusions?
Transudative
Exudative
Parapneumonic

Answer 7

Transudative: diuretics, Na restriction, therapeutic thoracentesis
Exudative: treat underlying disease
Parapneumonic:
- uncomplicated: abx
- complicated OR empyema: chest tube drainage, intrapleural injection of fibrinolytic agents (streptokinase, urokinase, tPA), surgical lysis of adhesions