Orientia tsutsugamushi infection with fever, eschar and lymphadenopathy that can progress to ARDS, AKI, shock, myocarditis and meningoencephalitis. Severe disease: IV doxycycline plus azithromycin for 7 days (INTREST).
At the bedside
Timed steps- 1
Clues
SuspectRural/bush/farm exposure, eschar (present in ~50% of Indian cases), regional lymphadenopathy, hepatosplenomegaly, ALT > AST, thrombocytopenia, ARDS.
- 2
IgM ELISA
TestIgM ELISA is the mainstay; IFA is gold standard; Weil-Felix is specific but insensitive; PCR of eschar or blood early.
- 3
Non-severe
TreatDoxycycline 100 mg 12-hourly for 7 days; azithromycin 500 mg daily in pregnancy and children.
- 4
Severe
TreatIV doxycycline + IV azithromycin for 7 days: INTREST composite of death, persistent complications or fever at day 7: 33% combination vs 47% doxycycline vs 48% azithromycin.
- 5
Organs
SupportLung-protective ventilation for ARDS; RRT; vasopressors; meningoencephalitis care; monitor for myocarditis and conduction defects.
Severe scrub typhus (with azithromycin)
Doxycycline
- Dose
- 200 mg load, then 100 mg every 12 h for 7 days
Severe scrub typhus (with doxycycline)
Azithromycin
- Dose
- 1 g on day 1, then 500 mg daily for 7 days
References
- 1
- 2
- 3
Scrub typhus
Step 1 of ~3
Decision: Organ dysfunction (ARDS, shock, AKI, CNS)?
Based on Varghese GM, Dayanand D, Gunasekaran K, et al. Educational use; follow local protocol.
Evidence
- INTREST 2023 (n = 794, India): combination IV doxycycline + azithromycin reduced the composite primary outcome vs either alone.
🇮🇳 India notes
- Endemic across the "tsutsugamushi triangle"; major cause of AFI and AES in Himachal, Uttarakhand, Tamil Nadu, Andhra, Northeast and Gorakhpur (AES).
References
- 1
- 2
- 3
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