Pleural Effusions Flashcards
What is Pleural Effusion?
The pleural space normally contains a very
thin layer of fluid.
• A pleural effusion is present when there is an excess quantity of fluid in the pleural space.
PATHOPHYSIOLOGY
• Pleural fluid accumulates when pleural fluid formation exceeds pleural fluid absorption.
• Normally, fluid enters the pleural space from the capillaries in the parietal pleura and is removed via the lymphatics in the parietal pleura.
• Other sources of pleural fluid accumulation includes;
– from the interstitial spaces of the lung via the visceral pleura and;
– From the peritoneal cavity via small holes in the diaphragm.
• Accordingly, a pleural effusion may develop when there is excess pleural fluid formation (from the interstitial spaces of the lung, the parietal pleura, or the peritoneal cavity) or when there is decreased fluid removal by the lymphatics.
CLINICAL FEATURES
• Symptoms are usually that of the underlying clinical condition
• Breathlessness (which may be the only
symptom) is common particularly when the
fluid is much
• Patients may also be asymptomatic
• Clinical signs include;
– Tachypnoea
– Contralateral tracheal deviation (when the volume is large): trachea shifts away from the affected side due to increased pressure in the affected hemithorax (same side is due to fibrosis)
– Reduced tactile fremitus and vocal resonance
– Stony dull percussion note
– Decreased or absent breath sounds
INVESTIGATIONS
Types?
What are you expected to see on Chest x-ray?
How much fluid is required to be seen on x-ray and clinical examination?
What’s is the investigation of choice?
Which should be used when a malignancy is expected?
• The presence of free pleural fluid can be
demonstrated with a lateral decubitus (lying on their side) chest X- ray, chest CT, or ultrasound.
• Chest X-ray (PA & erect) reveals;
– blunting of the costophrenic angle and;
– homogenous opacity arising from the lung base with the extent depending on the volume
• ≥300mls of fluid is required for it to be
detected on a PA chest X-ray
• ≥500mls is required for it to be detected
clinically
• Chest ultrasound is now the investigation of choice in the evaluation of pleural effusion.
• Chest CT is indicated when malignancy is
suspected
INVESTIGATIONS
• The presence of free pleural fluid can be
demonstrated with a lateral decubitus chest X- ray, chest CT, or ultrasound.
• Chest X-ray (PA & erect) reveals;
– blunting of the costophrenic angle and;
– homogenous opacity arising from the lung base with the extent depending on the volume
• ≥300mls of fluid is required for it to be
detected on a PA chest X-ray
• ≥500mls is required for it to be detected
clinically
• Chest ultrasound is now the investigation of choice in the evaluation of pleural effusion.
• Chest CT is indicated when malignancy is
suspected
Pleural fluid analysis
How do we differ between transudative and exudative pleural effusion?
• Usually indicated to determine the etiology of the pleural effusion
• Pleural fluid is obtained by thoracocentesis
• Biochemical analysis allows classification into transudate and exudates
• A transudative pleural effusion occurs when systemic factors that influence the formation and absorption of pleural fluid are altered.
• An exudative pleural effusion occurs when local factors that influence the formation and absorption of pleural fluid are altered.
• Transudative and exudative pleural effusions are distinguished using the Light’s criteria.
• Exudative pleural effusions meet at least one of the criteria, whereas transudative pleural effusions meet none
• Light’s criteria
– 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
• The primary reason for making this
differentiation is that additional diagnostic
procedures are indicated with exudative
effusions to define the cause of the local
disease.
• In some instances (e.g. left ventricular failure),
pleural fluid analysis may not be necessary
• Appropriate treatment of the underlying
condition (i.e. left ventricular failure in the above example) usually leads to resolution of the effusion)
• The most common cause of pleural effusion is left ventricular failure
• Leading causes of exudative pleural effusions are bacterial pneumonia, malignancy, viral infection, and pulmonary embolism.
Causes of transudative Pleural Effusions
• Congestive heart failure
• Cirrhosis
• Nephrotic syndrome
• Peritoneal dialysis
• Superior vena cava obstruction
• Myxedema
• Urinothorax
Causes of exudative Pleural Effusions
• Neoplastic diseases
– Metastatic disease
– Mesothelioma
• Infectious diseases
– Bacterial infections
– Tuberculosis
– Fungal infections
– Viral infections
– Parasitic infections
• Haemothorax
• Drugs e.g. amiodarone
• Pulmonary embolization
• Gastrointestinal disease
– Esophageal perforation
– Pancreatic disease
– Intraabdominal abscesses
– Diaphragmatic hernia
– After abdominal surgery
– Endoscopic variceal sclerotherapy
– After liver transplant
• And many more
MANAGEMENT OF PARAPNEUMONIC EFFUSION
• If the free fluid separates the lung from the chest
wall by >10 mm, a therapeutic thoracentesis
should be performed (fig 1).
• Factors indicating the likely need for drainage
include the following;
– Loculated pleural fluid
– Pleural fluid pH <7.20
– Pleural fluid glucose <3.3 mmol/L (<60 mg/dL)
– Positive Gram stain or culture of the pleural fluid
– Presence of gross pus in the pleural space
Malignant pleural effusion
What is the second most
common type of exudative pleural effusion?
What are the 3 tumors that cause 75% of all malignant pleural effusions?
How is diagnosis made?
• Malignant pleural effusions secondary to
metastatic disease are the second most
common type of exudative pleural effusion.
• The three tumors that cause ~75% of all
malignant pleural effusions are lung
carcinoma, breast carcinoma, and lymphoma
• Diagnosis usually is made via cytology of the pleural fluid.
• If the patient has a disabling dyspnoea that is relieved with a therapeutic thoracocentesis, one of the following procedures should be considered;
– insertion of a small indwelling catheter or;
– tube thoracostomy with pleurodesis (i.e.
instillation of a sclerosing agent such as
doxycycline or bleomycin).
What is the most common cause of pleural effusion?
Left ventricular heart failure
Leading cause of exudative pleural effusions?
bacterial pneumonia, malignancy, viral infection, and pulmonary embolism.
