Pleural effusion Flashcards
what is the definition of pleural effusion?
A pleural effusion results when fluid collects between the parietal and visceral pleural surfaces of the thorax.
what is the epidemiology of pleural effusion?
Congestive heart failure most common cause, followed by pneumonia and malignancy
what is the aetiology of pleural effusion?
Fluid determined by hydrostatic and oncotic pressure differences between layers of pleura.
A pleural effusion develops when the rate of fluid formation in the pleural space is greater than that of fluid removal
Transudates: pleural fluid protein ½ serum protein - Increase capillary permeability and impaired reabsorption
Pneumonia
Cancer
TB
Autoimmune conditions e.g. RA, SLE
PE
Benign Asbestos related pleural effusion
Pancreatitis/ Sub-diaphragmatic collections
Post Cardiac-surgery ‘Dressler syndrome’
Drug induced e.g. amiodarone, B-blockers, methotrexate, phenytoin
what are the risk factors for pleural effusion?
Congestive heart failure
Pneumonia
Malignancy
Recent coronary artery bypass
what is the pathophysiology of pleural effusion?
This regulated fluid balance is disrupted when local or systemic derangements occur. When local factors are altered, the fluid is protein- and lactate dehydrogenase (LDH)-rich and is called an exudate. Local factors include leaky capillaries from inflammation secondary to infection, infarction, or tumour. When systemic factors are altered, producing a pleural effusion, the fluid tends to have low protein and LDH levels and is called a transudate. This can be caused by an elevated pulmonary capillary pressure with heart failure, excess ascites with cirrhosis, or low oncotic pressure due to hypoalbuminemia (e.g., with nephrotic syndrome). In clinical practice, transudates are often multifactorial, with renal failure plus cardiac failure plus poor nutritional status being a common cause.
what are the key presentations of pleural effusion?
Asymptomatic Breathlessness Cough Pain Fever Reduced chest wall expansion Quiet breath sounds “Stony” Dull Percussion Reduced tactile/ vocal fremitus Meditational shift away from affected side
what are the first line and gold standard investigations for pleural effusion?
CXR - blunting of diaphragm (need 300 ml of fluid to show up on XR), meniscus of fluid, mediastinal shift in very severe cases
Thoracic ultrasound
CT chest
Pleural aspiration:
Biochemistry - pH, protein, LDH, glucose, amylase
Microscopy and culture - AAFB
Cytology
Medical thoracoscopy - pleural fluid drainage, biopsies for drainage, talc poudrage for pleurodesis
FBC - elevated WBC count in infective process
CRP - normal or elevated in acute bacterial infection
Blood culture - growth of organism
Sputum gram stain and culture - presence of pathological organisms
N-terminal pro-brain natriuretic peptide in pleural fluid - elevated in CHF
what are the differential diagnoses for pleural effusion?
Pleural thickening (could be due to asbestos related cancers)
Pulmonary collapse and consolidation
Elevated hemidiaphragm
how is pleural effusion managed?
Small - leave alone, treat conservatively
Infection / empyema - drain fluid, antibiotics
Malignant effusion - chest drain, re-current = long term chest drain
Transudates = no drain, treat underlying cause
how is pleural effusion managed?
Routine monitoring is not required following treatment of most pleural effusions if a clear cause has been found. If the patient again becomes symptomatic, then a chest x-ray is indicated.
what are the complications of pleural effusion?
atelectasis/ lobar collapse
Pneumothorax following thoracentesis
Re-expansion pulmonary oedema
what is the prognosis for pleural effusion?
If due to heart failure, cirrhosis, or malignancy, the effusion is likely to recur. However, most patients with a pleural effusion have no long-term sequelae.
