JC18 (Medicine) - Pleural Effusion and Lung Cancer Flashcards
Define Pleural effusion
4 types of Pleural Effusion
Pleural effusion: accumulation of serous fluid within pleural space
□ Empyema: accumulation of frank pus
□ Haemothorax: accumulation of blood
□ Chylothorax: accumulation of lymph
□ Hydropneumothorax: accumulation of fluid + air
Describe 4 factors that determine amount of fluid in pleural cavity (push and pull forces)
□ Hydrostatic pressure at arterial end
□ Oncotic pressure at venous end
□ Capillary permeability
□ Lymphatic drainage
Compare Transudative and exudative effusion causes
Symptoms of Pleural effusion
Dyspnoea: most common symptom, due to
□ Altered chest wall and diaphragm mechanics
□ Compression of lungs
□ Underlying lung or heart disease
Pleuritic chest pain: may not always be present, usually indicates exudative pathologies
□ Usually ↓intensity with ↑effusion size when inflamed pleural surfaces are no longer in contact
Signs of Pleural Effusion
Inspection: tachypnoea
Palpation:
□ ↓chest expansion
□ ± contralateral deviation of mediastinum
Percussion: stony dullness
Auscultation:
□ Increase transmission above effusion = bronchial breathing, ↑vocal resonance
□ Decrease transmission below effusion = ↓breath sounds, ↓vocal resonance
first-line investigations for pleural effusion
CXR
Ultrasound
CT ± PET/CT (if malignancy suspected or initial tap non-diagnostic)
Diagnostic thorcacentesis
Pleural Biopsy
Typical Xray appearance of pleural effusion
CXR: meniscus or blunted costophrenic angle seen
□ Requires ~200mL of fluid to be visible
□ May be loculated due to presence of pleural scarring or adhesions
Typical Ultrasound findings of pleural effusion
Ultrasound: more accurate than CXR
□ Transudate: clear hypoechoic space
□ Exudate: moving floating densities or septations
Indication for Diagnostic theracocentesis
Pleural fluid appearance for different causes of pleural effusion (4)
Indication: ALL effusions except bilateral effusion strongly suggestive of transudative process
Appearance:
Straw-coloured → serous (transudative)
Blood → traumatic haemothorax, malignancy, PE
Pus → empyema
Milky → chylothorax
Criteria for distinguishing transudative vs exudative pleural effusion
Light’s criteria: exudative if ≥1 positive
→ Pleural fluid:serum protein ratio > 0.5
→ Pleural fluid:serum LDH ratio > 0.6
→ Pleural fluid LDH > 2/3 of URL for serum
Pleural fluid biochemistry should be sent together with blood sample
List all metrics in diagnostic thoracentesis to find cause of effusion
- Appearance
- Glucose and pH compared to blood
- Cell count and WBC differentials (neutrophil vs lymphocyte predominant)
- Cytology for malignancy (2 taps minimum)
- Microbiology: Gram stain and culture, TB workup
Conditions that change glucose and pH level of pleural fluid
Glucose and pH: ↓Glc (lower than blood) and ↓pH (<7.30) in
Empyema (not in uncomplicated parapneumonic effusion)
Connective tissue disease, eg. RA, SLE
Malignant effusion
TB pleurisy → also a/w ↑adenosine deaminase (ADA) >40
Ruptured oesophagus
Indication for pleural biopsy
2 forms of pleural biopsy
Indication: exudative effusion with non-diagnostic thoracentesis (esp for TB and cancer)
1) Percutaneous:
- Blind if diffusely involved (eg. TB)
- CT- or USG-guided can be done but is inferior to thoracoscopic biopsy
2) Medical thoracoscopy (pleuroscopy) (allow therapeutic pleurodesis in the same procedure)
List management options for pleural effusion
- Treat underlying cause
- Therapeutic thoracentesis (therapeutic tap)
- Thoracostomy (chest tube) drainage
- In-dwelling pleural catheter (IDC) insertion
- Pleurodesis: chemical or surgical to obliterate pleural space
Risk factors of lung cancer
1) Environmental:
→ Smoking: responsible for ~90% CA lung, 40× death rate in smokers
→ Passive smoking
→ Toxin exposure: asbestos, cooking fumes
→ Radiation: thoracic RT, radon exposure
→ TB: ‘scar tumours’
2) Genetics: 1.5× risk with positive family Hx (e.g. EGFR mutation)
3) Previous lung conditions, eg. idiopathic pulmonary fibrosis (IPF)
Histological types of lung cancer
Prevalence of subtypes of lung cancer
□ Squamous cell carcinoma (SCC, 20-30%)
□ Adenocarcinoma (AD, 45-55%)
□ Large cell carcinoma (LCLC, 5-10%)
□ Small cell carcinoma (SCLC, 5-10%)
High-risk genetic changes asso. with lung cancer
EGFR mutation (55% in local AD) ALK translocation (5% in local AD) KRAS mutation (5-10% in local AD)
Most common presenting symptoms of Lung Cancer
cough (45-74%),
weight loss (46-68%),
SOB (37-58%),
chest pain (27-49%),
haemoptysis (27-29%),
bone pain (20-21%),
hoarseness (8-18%).
Primary lung cancer Tumor mass effects
Bronchial mucosa ulceration:
- Cough (80%): usually dry, ± sputum if secondary infection
- Haemoptysis (70%): common esp in central bronchial tumours
Partial Bronchial obstruction:
- Monophonic, unilateral wheeze not cleared with coughing
- Recurrent pneumonia due to poor drainage
- Stridor
Complete Bronchial obstruction:
- Lung Collapse
Primary lung cancer - List 10 structures affected in intrathoracic spread
- Lymphangitis carcinomatosis
- Pleural effusion
- Pericardial effusion and cardiac tamponade
- Chest wall and ribs (pain)
- Phrenic nerve damage and diaphragm paralysis
- SVC obstruction (emergency)
- Left RLN damage (hoarseness, bovine cough)
- Brachial plexus (Pancoast syndrome)
- Inferior cervical sympathetic chain - Horner’s syndrome
- Esophagus (dysphagia)
S/S of SVC obstruction
- Dyspnoea and stridor
- Facial plethora, headache and conjunctiva oedema
- Early morning headache
- Dilated veins on chest wall and neck
- Pemberton’s sign: exaggeration of symptoms when lift both arms (narrow thoracic inlet → ↑obstruction)
S/S of pancoast syndrome
pain in inner aspect of arm ± small hand muscle wasting
classically a/w NSCLC, only <5% SCLC
S/S of Horner syndrome
SPAM = sunken eyeball, partial ptosis, anhidrosis, miosis
(ipsilateral partial ptosis, miosis, enophthalmos, anhidrosis)
