A prospective study of the effectiveness of clinical RGA (Rathi Goodman Aghai) score in relation with PCR in the diagnosis of scrub typhus

Abstract

Background: Rickettsial diseases are emerging as an important cause of acute undifferentiated febrile illness throughout the Asia-Pacific region. Rickettsial infections are generally incapacitating and difficult to diagnose; untreated cases have case fatality rates as high as 30-45% with multiple organ dysfunction, if not promptly diagnosed and appropriately treated. Prompt antibiotic therapy, even based on suspicion, shortens the course of the disease and lowers the risk of complications and in turn reduces morbidity and mortality due to rickettsial diseases. Objectives: To study the clinical RGA score, in relation with PCR in the diagnosis of Scrub Typhus cases admitted in medical college hospital. Methodology: It is prospective observational study. The present study was conducted at the department of Paediatrics, SVRR Govt. General Hospital, Tirupati for a period of 1 year. A total of 99 cases in the age group of 1 month to 12 years were taken into the study by considering the inclusion and exclusion criteria. Results: RGA scoring was done for every case and blood samples were drawn for IgM ELISA and PCR. There is higher incidence of scrub typhus in the age group of 1-5 years accounting to56.6%. Males outnumber females. Male: Female ratio is 1.6:1. Majority of the children are from rural area constituting 69.7% of the total cases. Majority of the cases had RGA score >14(73.7%). RGA score of >14 shows a sensitivity of 92% and specificity of 83.3% when compared with the PCR. There was an increase in the sensitivity when the cut-off was lowered. RGA >9 showed a sensitivity of 97%. RGA score of >14 showed a sensitivity of 93.8% in those with both IgM ELISA and PCR positive. IgM ELISA shows a sensitivity of 73% when compared with PCR. Conclusion: Scrub typhus has become a leading infectious disease in India and an important cause of infectious fever. The proposed scoring system can be used for early detection, treatment and prevention of mortality and morbidity from spotted fever group.