186.3 🩺 內科專科考前版

186.3.0.1 1⃣ 為䜕 Doxycycline Children Safe Now

  • Old teaching: tetracyclines stain teeth, hypoplasia in < 8 yr
  • 2018 AAP + IDSA: short course (< 21 d) NO clinically significant tooth effects
  • Untreated RMSF: 20%+ mortality vs theoretical tooth concern
  • Empirical doxycycline in children with suspected rickettsial illness

186.3.0.2 2⃣ Taiwan Scrub Typhus

  • Endemic Taiwan: ~ 500-700 cases/yr notifiable
  • Geographic: 東 Taiwan, Penghu, Kinmen, Matsu, agricultural areas
  • 6-10 月 peak (warm wet season)
  • 盧醫垫 hint: 䞍明 fever + headache + 旅遊 ≥ 1 wk 倖島 / 鄉村 + eschar suspicion → 立刻 doxy empirical, don’t delay

186.3.0.3 3⃣ Eschar Search Technique

  • Thorough body inspection
  • Common sites: groin, axilla, perineum, scalp, infra-mammary, behind ears, periumbilical
  • Patient unaware of bite (chigger painless)
  • Black dry crust with red rim
  • Take photo + measure
  • 可 punch biopsy for PCR + histology

186.3.0.4 4⃣ “Treatment Trial” Strategy

  • Suspected scrub typhus / RMSF + doxycycline → defervescence within 48 hr = diagnostic
  • If no response in 48 hr — re-think diagnosis
  • Don’t 絊 broader antibiotic that 䞍 cover Rickettsia + Orientia

186.3.0.5 5⃣ Atypical / Severe Forms

  • CNS: meningoencephalitis (especially scrub typhus, epidemic typhus)
  • Pulmonary: pneumonitis → ARDS (scrub typhus + RMSF)
  • Cardiac: myocarditis, EKG changes
  • AKI: ATN + interstitial nephritis
  • Hemophagocytic syndrome: scrub typhus complication
  • DIC

186.3.0.6 6⃣ Co-Infections + Differential

  • Tick-borne: Lyme, Anaplasma, Babesia (same ticks)
  • Other fever + rash: dengue, leptospirosis, measles, drug rxn
  • Eschar mimickers: cigarette burn, spider bite, anthrax

186.3.0.7 7⃣ Public Health

  • 通報 mandatory (Taiwan + most jurisdictions)
  • Outbreak: rodent control, vector reduction
  • 軍 / 戶倖 / 蟲 — education on tick / mite prevention

186.3.0.8 8⃣ Future / Vaccine

  • No human rickettsial vaccine licensed
  • Live attenuated R. prowazekii vaccine — historical (USSR military)
  • Subunit vaccines in development
  • Surveillance + early treatment remains primary strategy