JK SCIENCE Vol. 12 No. 2, April-June 2010 www.jkscience.org 83 From the Peoples College of Medical Sciences Campus, PCMS, Bhanpur, Bhopal-462010 Madhya Pradesh-India. Correspondence to : Dr S.N. Kaore, Senior MIG - C/4, PCMS Campus, PCMS, Bhanpur, Bhopal-462010 Madhya Pradesh - India ARDS in Scrub Typhus S.N. Kaore, P.Sharma,V.K.Yadav, R.Sharma, N.M. Kaore Introduction Scrub typhus is a mite-borne infectious disease caused by Orientia tsutsugamushi.It is an acute febrile illness which generally causes non-specific symptoms and signs. The clinical manifestations of this disease range from sub-clinical disease to organ failure to fatal disease. Deaths are attributable to late presentation, delayed diagnosis, and drug resistance.Acute respiratory distress syndrome (ARDS) is a serious complication of scrub typhus. The mortality rate for the scrub typhus patients with ARDS can range upto 25% (1) . Recently with increasing trend of outdoor recreation activities, mountaineering, urbanization into rural areas, even physicians those who are not in the endemic areas may encounter the disease and should be aware of its symptoms and complications. If there is delay in the initiation of the appropriate antimicrobial therapy patient may present with serious complications when diagnosis is delayed or patient is not treated with appropriate antibiotic, the scrub typhus can present with serious complications such as renal failure, myocarditis, septic shock, meningoencephalitis and rarely acute respiratory distress syndrome that may lead to death.The pulmonary manifestations of scrub typhus are varying grades of bronchitis and interstitial pneumonitis progressing to ARDS (1). Acute respiratory distress syndrome is defined as an acute and persistent lung inflammation with increased vascular permeability and is most often associated with sepsis syndrome, aspiration, primary pneumonia, or multiple traumas (2). Pathology of ARDS The pathologic progression of ARDS reflects the sequentially occurring exudative, organizing (fibroproliferative) and fibrotic stages. There are reports of diffuse alveolar damage in the organizing stage without evidence of vasculitis (3). Pathological findings in ARDS patients on gross inspection reveal oedematous and haemorrhagic lungs. Microscopic examination revealed diffuse alveolar damage with hyaline membrane formation and interstitial pneumonitis with infiltration of inflammatory cells. Immunohistochemical stain showed O. tsutsugamushi antigen depositions in the endothelial cells. It is also possible to demonstrated iNOS in the alveolar macrophages and lung tissue debris in both cases. Thus, direct endothelial cell invasion of the organism and marked iNOS expression may be involved in the pathogenesis of ARDS associated with scrub typhus (4). Clinical Studies with ARDS A retrospective study in Taiwan, China reviewed the medical records of 72 patients diagnosed with scrub typhus from January 1998 to August 2006. Patients with ARDS were included in study while patients without ARDS served as controls. Mortality rate was found to be 25%. The study highlighted that significant predictors of ARDS are initial presentations of dyspnea and cough, white blood cell count, hematocrit, total bilirubin, and delayed used of appropriate antibiotics while albumin, prothrombin time, and delayed use of appropriate antibiotics are independent predictors of ARDS. Identification and keeping these relative risk factors in the mind may help clinicians to evaluate & identify clinical cases of scrub typhus with ARDS early (5). In the same study group the biochemical parameters were studied in detail, which indicated that WBC counts of the ARDS group were significantly higher than those of the control group, which reflects the seriousness of infection in the ARDS group. Hematocrit in the ARDS group was significantly lower than that of the control group, which suggested that the ARDS group was more anemic than the control group. Although all liver enzyme levels (AST, ALT, ALP, and total bilirubin) were increased in both the ARDS and control groups, only the total bilirubin level was significantly higher in the ARDS group than in the control group. Therefore, a scrub typhus patient with severe infection, anemia and jaundice may be considered to be at high risk for developing ARDS (5). In general, fever for more than one week was the only common manifestation in patients clinically and serologically confirmed to have scrub typhus. At times, it may present without the typical symptom of high fever, as in case of an aged patient in Japan and subsequently developed the complication of ARDS but improved dramatically on timely intervention with minocycline and supportive measures (6) In another study, scrub typhus patients presented in SCRUB TYPHUS EMERGING THREAT COMPLICATION