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World J Crit Care Med. Aug 4, 2015; 4(3): 244-250
Published online Aug 4, 2015. doi: 10.5492/wjccm.v4.i3.244
Severe scrub typhus infection: Clinical features, diagnostic challenges and management
John Victor Peter, Thomas I Sudarsan, John Anthony J Prakash, George M Varghese
John Victor Peter, Thomas I Sudarsan, Medical Intensive Care Unit, Christian Medical College, Vellore 632004, Tamil Nadu, India
John Anthony J Prakash, Department of Microbiology, Christian Medical College, Vellore 632004, Tamil Nadu, India
George M Varghese, Department of Infectious Diseases, Christian Medical College, Vellore 632004, Tamil Nadu, India
Author contributions: Peter JV contributed to the study concept; Peter JV, Sudarsan TI, Prakash JAJ and Varghese GM searched the literature and obtained the revelant articles; Peter JV, Sudarsan TI, Prakash JAJ and Varghese GM wrote the article; Peter JV, Sudarsan TI, Prakash JAJ and Varghese GM approved the final manuscript for publication.
Conflict-of-interest statement: There is no conflict of interest or financial disclosure for all the authors.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. John Victor Peter, Professor, Head, Medical Intensive Care Unit, Christian Medical College, Vellore 632004, Tamil Nadu, India. peterjohnvictor@yahoo.com.au
Telephone: +91-416-2282693 Fax: +91-416-2202035
Received: November 6, 2014
Peer-review started: November 8, 2014
First decision: January 8, 2015
Revised: January 27, 2015
Accepted: April 8, 2015
Article in press: April 9, 2015
Published online: August 4, 2015
Processing time: 283 Days and 21.5 Hours
Abstract

Scrub typhus infection is an important cause of acute undifferentiated fever in South East Asia. The clinical picture is characterized by sudden onset fever with chills and non-specific symptoms that include headache, myalgia, sweating and vomiting. The presence of an eschar, in about half the patients with proven scrub typhus infection and usually seen in the axilla, groin or inguinal region, is characteristic of scrub typhus. Common laboratory findings are elevated liver transaminases, thrombocytopenia and leukocytosis. About a third of patients admitted to hospital with scrub typhus infection have evidence of organ dysfunction that may include respiratory failure, circulatory shock, mild renal or hepatic dysfunction, central nervous system involvement or hematological abnormalities. Since the symptoms and signs are non-specific and resemble other tropical infections like malaria, enteric fever, dengue or leptospirosis, appropriate laboratory tests are necessary to confirm diagnosis. Serological assays are the mainstay of diagnosis as they are easy to perform; the reference test is the indirect immunofluorescence assay (IFA) for the detection of IgM antibodies. However in clinical practice, the enzyme-linked immuno-sorbent assay is done due to the ease of performing this test and a good sensitivity and sensitivity when compared with the IFA. Paired samples, obtained at least two weeks apart, demonstrating a ≥ 4 fold rise in titre, is necessary for confirmation of serologic diagnosis. The mainstay of treatment is the tetracycline group of antibiotics or chloramphenicol although macrolides are used alternatively. In mild cases, recovery is complete. In severe cases with multi-organ failure, mortality may be as high as 24%.

Keywords: Rickettsia; Diagnosis; Management; Outcome; Multi-organ failure

Core tip: Scrub typhus is an important differential diagnosis in patients who present with acute undifferentiated fever in South East Asia. Since the presentation may be non-specific, with features of organ failure in those with severe infection, early diagnosis and appropriate management is crucial. The presence of an eschar suggests scrub typhus infection. The diagnosis may be confirmed on serological assays, the reference test being the indirect immunofluorescence test for the detection of IgM antibodies. In those with mild infection, fever defervescence occurs in about 2-d with Doxycycline therapy.