Orientia tsutsugamushi: Difference between revisions

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== Management ==
== Management ==
* [[Doxycycline]] 100 mg po bid for 7 days
* [[Doxycycline]] 100 mg po bid for 7 days
* Alternative: [[azithromycin]] 500 mg p.o. daily for 1-3 days
* For severe disease, combination [[doxycycline]] and [[azithromycin]] for 7 days<ref>Varghese GM, Dayanand D, Gunasekaran K, Kundu D, Wyawahare M, Sharma N, Chaudhry D, Mahajan SK, Saravu K, Aruldhas BW, Mathew BS, Nair RG, Newbigging N, Mathew A, Abhilash KPP, Biswal M, Prasad AH, Zachariah A, Iyadurai R, Hansdak SG, Sathyendra S, Sudarsanam TD, Prakash JAJ, Manesh A, Mohan A, Tarning J, Blacksell SD, Peerawaranun P, Waithira N, Mukaka M, Cheah PY, Peter JV, Abraham OC, Day NPJ; INTREST Trial Investigators. Intravenous Doxycycline, Azithromycin, or Both for Severe Scrub Typhus. N Engl J Med. 2023 Mar 2;388(9):792-803. doi: 10.1056/NEJMoa2208449. PMID: 36856615.</ref>
** Dosing may be unusual: doxycycline 200 mg bid x2 followed by 100 mg bid; azithromycin 500 mg bid x2 followed by 500 mg daily


{{DISPLAYTITLE:''Orientia tsutsugamushi''}}
{{DISPLAYTITLE:''Orientia tsutsugamushi''}}

Revision as of 15:15, 2 March 2023

  • Chigger-borne rickettsial infection caused by the intracellular Gram-negative bacterium Orientia tsutsugamushi that causes scrub typhus

Background

Life Cycle

  • The entire life cycle is maintained within Leptotrombidium mites by vertical/transovarial transmission
  • Leptotrombidium larvae (called chiggers) normally feed on rodents, and occasionally humans, who are dead-end hosts

Epidemiology

  • Most common in rural Asia and western Australia, as well as other parts of eastern Asia, including Russia and India

Clinical Manifestations

  • Fever, headache, myalgia, lymphadenopathy, and an eschar
    • Lymphadenopathy sometimes grouped near the eschar
    • Should almost always be able to find the eschar if you look hard enough
  • Transient pale macular rash
  • May have cough
  • May have mental status changes and hepatosplenomegaly
  • In severe cases, may progress to multiorgan failure and hemorrhage
  • After treatment, may relapse
  • Infection also decreases HIV viral load and can lead to immune reconstitution

Diagnosis

  • Four-fold rise in immunofluorescence serology
  • PCR on eschar, blood, or lymph node biopsy

Management

  • Doxycycline 100 mg po bid for 7 days
  • Alternative: azithromycin 500 mg p.o. daily for 1-3 days
  • For severe disease, combination doxycycline and azithromycin for 7 days[1]
    • Dosing may be unusual: doxycycline 200 mg bid x2 followed by 100 mg bid; azithromycin 500 mg bid x2 followed by 500 mg daily
  1. Varghese GM, Dayanand D, Gunasekaran K, Kundu D, Wyawahare M, Sharma N, Chaudhry D, Mahajan SK, Saravu K, Aruldhas BW, Mathew BS, Nair RG, Newbigging N, Mathew A, Abhilash KPP, Biswal M, Prasad AH, Zachariah A, Iyadurai R, Hansdak SG, Sathyendra S, Sudarsanam TD, Prakash JAJ, Manesh A, Mohan A, Tarning J, Blacksell SD, Peerawaranun P, Waithira N, Mukaka M, Cheah PY, Peter JV, Abraham OC, Day NPJ; INTREST Trial Investigators. Intravenous Doxycycline, Azithromycin, or Both for Severe Scrub Typhus. N Engl J Med. 2023 Mar 2;388(9):792-803. doi: 10.1056/NEJMoa2208449. PMID: 36856615.