Pulmonary tuberculosis

Background

Microbiology

• Caused by Mycobacterium tuberculosis

Clinical Presentation

• Subacute or chronic cough (at least 2 to 3 weeks) eventually becoming productive and occasionally involving hemoptysis
  • Should be suspected in any patient with cough and HIV infection
• Constitutional symptoms, with fevers, night sweats, and unexplained weight loss
• Usually from reactivation of latent tuberculosis infection, and usually reactivates in lung apices
• May transiently improve with partially-active antibiotics such as fluoroquinolones

Investigations

• Spontaneous sputum, induced sputum, or bronchoalveolar lavage specimens should be sent for
  • Acid-fast staining of a smear
  • Culture
  • PCR

Management

• Standard HREZ x2mo then HR x4mo
  • Isoniazid 5mg/kg/d, max 300mg daily
  • Rifampin 10mg/kg/d
  • Pyrazinamide 25mg/kg/d, max 2g daily
  • Ethambutol 20mg/kg/d, max 1.2g daily
  • Pyridoxine 25 mg po daily
• Standard duration for uncomplicated disease is 6 months, but should be extended to 9 months if high-risk (including smear positive at 2 months or cavitations)
• Airborne precautions until:
  • Treated for at least 2 weeks
  • 3x negative sputum smears, which can be collected hourly, but ideally at 8- to 24-hour intervals, including one early morning collection
  • Improvement in symptoms