10- TB Dx

• Chest X-ray

  • Upper lobe patchy/nodular infiltrates with cavitation
  • Healed primary Tb: Ghon complex (calcified primary focus w/LN)
  • Ranke complex= Ghon complex calcified & fibrosis
• Sputum

  1. Serial sputum samples, at least 3 occasions, ideally early morning

  2. Sputum smear for acid-fast bacilli (Ziehl-Neelsen stain)

  3. Definitive Dx is by sputum culture (takes 3 weeks, must be done for antibiotic sensitivity) and PCR (more rapid, nucleic acid amplification test)
• Sputum smear for acid-fast bacilli

  If +ve sputum smear à infectious (needs isolation) for AFB
• Extrapulmonary

  • Needs high index of suspicion + organism in [LN biopsy, bone biopsy, urine testing, or aspiration of pericardial fluid]
  • If military: must look for CNS Tb: umbar puncture & CSF exam (high risk of meningitis) (2-3g protein lymphocytosis)