The Good Doctor

Category: BREATHING

  • Thoracentesis – What to Measure?

    Features to evaluate of a thoracentesis aspirate:

    • specific gravity
    • WCC and differential
    • Protein and Glucose concentrations
    • Lactate Dehydrogenase
    • pH and pCO2
    • amylase
    • Gram stain + cultures (+ AFB)
    • exfoliative cytology
    • ±rheumatoid factor (RF)
    • ± complement (C3/C4) levels

    Pearls:

    • low pH (< 7.20) – often indicates empyema probably requiring tube drainage
    • very low glucose – rheumatoid arthritis
    • very high amylase – pancreatitis, ruptured oesophagus

    Signs of pleural fluid:

    • percussion: very dull
    • breath sounds: absent (± bronchial breathing above)
    • vocal resonance / fremitus: absent
    • added sounds: nil

    Causes of a pleural effusion:

    1. carcinoma of the bronchus
    2. lobar pneumonia – bilateral
    3. pulmonary embolus – bilateral
    4. right heart failure – bilateral
    5. subdiaphragmatic pathology
      1. cirrhosis
      2. nephrotic syndrome
      3. acute pancreatitis
    6. others
      1. rheumatoid arthritis
      2. systemic lupus erythematosus
      3. mesothelioma

    Transudate (< 30 g/L)

    • right heart failure
    • nephrotic syndrome
    • liver failure
    • Meig’s syndrome

    Exudate (> 30 g/L)

    • pneumonia
    • neoplasm
      • bronchial carcinoma
      • metastases
      • mesothelioma
    • tuberculosis
    • pulmonary infarction
    • subphrenic abscess
    • pancreatitis
    • connective tissue diseases
      • rheumatoid arthritis
      • systemic lupus erythematosus