192.3 🩺 內科專科考前版

192.3.0.1 1⃣ MDR / XDR Definitions (WHO 2021 Update)

  • MDR-TB: R to INH + Rifampin
  • Pre-XDR-TB: MDR + FQ R
  • XDR-TB: MDR + FQ R + bedaquiline OR linezolid R
  • Old XDR (pre-2021): MDR + FQ R + aminoglycoside R

192.3.0.2 2⃣ BPaL/BPaLM Patient Selection

  • Pulmonary MDR / Pre-XDR / XDR-TB ≥ 14 yr
  • HIV co-infection ok
  • Pregnancy / lactation: caution (some data, drug interactions with ART)
  • Diabetes / hepatic / renal disease — adjust carefully
  • Counsel on linezolid bone marrow toxicity (monthly CBC)
  • QTc baseline + monitor (bedaquiline)

192.3.0.3 3⃣ TB Drug Resistance Testing

  • GeneXpert MTB/RIF — rapid (1-2 hr) rifampin resistance + TB detection; first-line WHO
  • Xpert MTB/XDR — extended panel: INH, FQ, aminoglycoside R
  • Sequencing: comprehensive (whole genome)
  • AST cultures: gold standard but slow (4-12 wk)

192.3.0.4 4⃣ HIV + TB

  • TB is leading cause of death in HIV globally
  • IRIS (Immune Reconstitution Inflammatory Syndrome) when ART started
  • Drug interactions: rifampin + most ART → enzyme inducer
    • Switch rifampin → rifabutin for most ART regimens
    • Or use rifampin + DTG-based regimen (compatible)
  • èµ· ART 2-8 wk after TB treatment in non-CNS, 2-4 wk in CNS

192.3.0.5 5⃣ Pregnancy + TB Treatment

  • Don’t delay treatment
  • RIPE all considered safe except occasional concern about PZA (US slightly more cautious than WHO)
  • Pyridoxine for INH mandatory (pyridoxine increased need in pregnancy)
  • Streptomycin contraindicated (8th nerve fetal damage)
  • DOT + close monitoring

192.3.0.6 6⃣ Drug Levels (TDM)

  • Useful in:
    • Treatment failure
    • HIV
    • Diabetes (PK changes)
    • Malabsorption
    • Drug interactions
  • INH, rifampin, ethambutol levels
  • Specialty labs

192.3.0.7 7⃣ Renal / Hepatic Adjustment

  • Renal failure: ethambutol, PZA, aminoglycosides — reduce dose / extend interval; INH + rifampin generally OK
  • Hepatic disease:
    • Mild-moderate: INH or PZA reduce, monitor closely
    • Severe: use rifampin + ethambutol + FQ + injectable (no INH, no PZA)

192.3.0.8 8⃣ TB Stewardship

  • Empirical CAP — don’t auto-cover TB unless suspicion (cavitary, weight loss, night sweats, immigrant, immunocompromise)
  • Don’t initiate single-drug ANY anti-TB drug (selects resistance)
  • Always combination + correct regimen
  • 通報 mandatory
  • DOT / vDOT