Makindo Medical Notes.com

Related Subjects: |Assessing Breathlessness

The appearance of the meniscus is a visual illusion due to the shape of the chest thorax with more fluid seen laterally. There is no real meniscus. Diagnostic tap with 20 ml syringe with a 21 G needle to obtain 20 mL of fluid. This should be sent to the laboratory for Protein/LDH, Cell count, Culture, including TB, Large volume really needed to be spun down for cytology for malignant cells.

About

• Collection of fluid within the pleural space impairs lung function
• May suggest underlying lung or pleural pathology

Types

• Pleural effusion: fluid in pleural space
• Pneumothorax: air in pleural space
• Empyema: pus in pleural space
• Haemothorax: Blood in pleural space
• Chylothorax: Chyle in pleural space

Aetiology

• Many mechanisms - inflammation. malignancy, altered local permeability and altered osmotic forces.
• Classically divided by protein levels into high protein exudates and low protein transudates which helps narrow down cause

Clinical (needs > 500 mls to be clinically detectable)

• Increasing breathlessness
• Pleuritic type chest pain
• Reduced chest wall movement
• Stony dull percussion note
• Deviation of the trachea and mediastinum away with a massive effusion
• Decreased vocal resonance
• Absent breath sounds
• Bronchial breath sounds at top of effusion

Light's criteria: Fluid is exudate if one of the following Light criteria is present

• Effusion protein/serum protein ratio greater than 0.5
• Effusion LDH/serum LDH ratio greater than 0.6
• Effusion LDH level greater than two-thirds the upper limit of the laboratory's reference range of serum LDH

Classical Findings

• Cancer: fluid is serous exudate +/- blood. Malignant cells may be seen when spun down. Positive pleural biopsy (40%).
• Cardiac failure: Serous, straw-coloured transudate. May respond to fluid restriction and diuretics. The BNP is elevated.
• Tuberculosis: Clear amber-coloured fluid with Lymphocytes (occasionally polymorphs) Exudate. Positive tuberculin test. Mycobacterium tuberculosis isolated from pleural fluid in only 1/5th and pleural biopsy more useful. Raised adenosine deaminase
• Pulmonary infarction: clear or blood-stained. Exudate or transudate. PE and infarct are seen on CTPA
• Rheumatoid disease: serous often turbid with a high number of Lymphocytes. Positive Rheumatoid factor and anti-cyclic citrullinated peptide (anti-CCP) antibodies. Cholesterol is seen in chronic effusion. Classically low glucose.
• Systemic lupus erythematosus: serous lymphocytic. Positive Antinuclear factor or anti-DNA positive.
• Acute pancreatitis: clear serous or bloody fluid. Elevated amylase in pleural fluid
• Chylothorax: Milky fluid. Obstruction of the thoracic duct. Fluid full of Chylomicrons

Causes using Light's criteria

• Exudates: Increased protein or LDH
  • Abdominal infections, abscess, ascites,
  • Meigs syndrome, pancreatitis
  • Churg-Strauss disease, lupus, rheumatoid arthritis, Wegener granulomatosis
  • Hypothyroidism, ovarian hyperstimulation
  • Drug-induced, oesophageal perforation, a feeding tube in lung
  • Lung abscess, bacterial pneumonia, fungal disease, parasites, tuberculosis
  • Acute respiratory distress syndrome (ARDS)
  • Asbestosis, pancreatitis, radiation, sarcoidosis, uraemia
  • Chylothorax, malignancy, lymphangiectasia
  • Carcinoma, lymphoma, leukaemia, mesothelioma, paraproteinemia
• Transudates
  • Atelectasis, Cerebrospinal fluid (CSF) leak into pleural space
  • Thoracic spine injury, ventriculoperitoneal (VP) shunt dysfunction
  • Heart failure, Liver failure, Nephrotic syndrome and Hypoalbuminemia
  • Iatrogenic: Misplaced catheter into lung
  • Peritoneal dialysis
  • Urinothorax: Due to obstructive uropathy

Therapeutic tap

• Indicated when there is a local exudative cause to ease breathlessness. Avoid in heart failure and low protein states and diuretics were given. A large volume can be useful to send for cytology.
• Ideally drain the effusion with an intercostal drain usually placed low over the diaphragm. General advice now to use ultrasound to guide placement is useful.
• Place a small-bore (10–14 F) intercostal drain. Clamp intermittently to limit flow to 1 L in the first hour. Rapid drainage can cause pulmonary oedema especially if re-expansion of the collapsed lung is associated with a pneumothorax. Once drained generally removed.
• A more expansive drainage process may be needed with significant empyema which requires antibiotics and drainage of viscous infected fluids. As ever take specialist advice.