Old Tuberculosis

Relevant physical signs

• Thoracoplasty (surgical procedure designed to collapse a tuberculous cavity)
  • Deviation of the trachea towards the affected side
  • Flattening of the chest wall on the affected side
  • Posterior thoracotomy scar
  • Absent ribs (usually 3^rd – 8^th)
  • Dull percussion note over affected area
  • Reduced breath sounds over the affected area (but preserved at bases)
  • Reduced vocal resonance over the affected area
• Phrenic nerve crush (causes ipsilateral diaphragmatic paralysis and basal lobe collapse)
  • Trachea usually central as it affects the bases
  • Scar over ipsilateral supraclavicular region
  • Reduced chest expansion over ipsilateral base
  • Dull percussion note
  • Reduced air entry and vocal resonance
• No other physical findings on examination

Differential diagnosis

• Thoracoplasty
  • Lobectomy
  • Pneumonectomy
  • Fibrothorax
  • Collapse of a lung lobe
• Phrenic nerve crush
  • Phrenic nerve palsy
  • Hepatomegaly / splenomegaly
  • Hiatus hernia
  • Lower lobe collapse
  • Lower lobectomy
  • Pleural effusion

Investigations of pulmonary tuberculosis

• Full blood count, renal function, liver function, baseline Ishihara chart (prior to starting anti-tuberculous Rx)
• Chest radiograph to assess extent of disease
• Sputum for acid fast bacilli smear and culture, molecular detection of MTB
• Bronchoscopy and bronchoalveolar lavage if index of suspicion is high and sputum samples are negative
• Diagnosis of latent TB (for patients at risk of TB re-activation and those in contact with active TB)
  • Tuberculin skin test
  • Interferon-gamma release assays (QuantiFERON-TB and TB-SPOT)

Management

• Acute
  • Oxygen supplementation, intubation and mechanical ventilation if necessary
  • Bronchial artery embolisation / bronchoscopy / surgical resection for haemoptysis
• Antibiotic therapy
  • Rifampicin (6 months) – orange discolouration of saliva, urine, hepatotoxicity, rash
  • Isoniazid + pyridoxine (6 months) – hepatotoxicity, neurotoxicity
  • Ethambutol (2 months) – ocular toxicity, hepatotoxicity, rash, eosinophilia
  • Pyrazinamide (2 months) – hepatotoxicity, arthralgia, interstitial nephritis
  • Stop if transaminitis is > 3x the upper limit of normal with symptoms, or 5x without symptoms