187.3 🩺 內科專科考前版

187.3.0.1 1⃣ Same Ixodes Tick — Disease Spectrum

  • Lyme (B. burgdorferi): 36-48 hr attachment
  • HGA (A. phagocytophilum): 24 hr attachment
  • Babesia (B. microti): 36-48 hr attachment
  • B. miyamotoi: 24 hr
  • Powassan virus: 15 minutes (!)
  • Co-infections in 10-30% of Lyme cases

187.3.0.2 2⃣ Babesia + HGA in Asplenic

  • Asplenic + tick exposure + fever + hemolytic anemia + thrombocytopenia → emergent
  • Babesia treatment: atovaquone + azithromycin or clinda + quinine
  • Severe asplenic Babesia → exchange transfusion + atovaquone-azithro + clinda + quinine combo
  • HGA worsens severity
  • Tick-borne panel + 急 hematology consult

187.3.0.3 3⃣ HME Severity in Immunocompromise

  • HIV / chemotherapy / transplant / splenectomy — severe
  • Mortality higher
  • HLH / multi-organ failure
  • Higher dose / longer doxycycline

187.3.0.4 4⃣ Pregnancy

  • Doxy contraindicated traditionally; IDSA 2024: short course OK if life-threatening
  • Rifampin 300 mg bid × 7-10d — primary alternative
  • Higher pediatric / fetal mortality if untreated HME / HGA

187.3.0.5 5⃣ HLH (Hemophagocytic Lymphohistiocytosis)

  • Secondary HLH from severe HME/HGA
  • Persistent fever + cytopenia + hyperferritinemia + hepatosplenomegaly + hypertriglyceridemia
  • Bone marrow biopsy: hemophagocytosis
  • Treat underlying + HLH protocol (steroid, IVIG, etoposide)

187.3.0.6 6⃣ Tick-Borne Disease Panel

  • Multi-PCR panel (BioFire / Mayo Clinic)
  • Lyme, HGA, HME, Babesia, B. miyamotoi, Powassan
  • Faster than serology
  • Empirical treatment guided by clinical + initial panel results

187.3.0.7 7⃣ 健保 / Taiwan

  • 眕芋 ehrlichiosis/anaplasmosis Taiwan
  • 旅遊 returnees from endemic areas
  • 健保 doxycycline covered
  • Tick-borne disease awareness in 旅遊 medicine

187.3.0.8 8⃣ Prevention

  • Tick avoidance (same as Lyme — Ch 185)
  • Permethrin clothing
  • DEET / picaridin
  • Tick checks after outdoor
  • Remove tick within hours