Journal of Internal Medicine and Health Affairs

Abstract

Scrub typhus is a zoonotic disease caused by the rickettsial organism Orientia Tsutsugamushi. It is one of the most underdiagnosed and under reported febrile illness world wide.  It is one of the main differential diagnosis for acute febrile illness.

Methodology - Hospital based observational study carried out over a period of 6 months (January 2022 – June 2022).

Results - Among the 80 seropositive patients, 35 patients were male and 45 patients were female, 17.5 % patients were agriculture worker by occupation.  Most common symptoms were fever, nausea, vomiting, headache, myalgia, cough, pain abdomen and puffiness of face. he organ system dysfunction, renal failure is the most common followed by hepatitis, CNS dysfunction and ARDS. Out of 80 patients 22 patients required ICU admission and 12 patients were dead. Mortality rate was 22%.

Conclusion - Scrub typhus is a severe acute febrile sickness that has a high death rate. Serious life-threatening consequences of this illness include respiratory dysfunction, shock, and abrupt renal failure. To avoid complications that might be fatal, prompt diagnosis, prompt antibiotic medication, and thorough supportive care are essential.

Introduction

The "tsutsugamushi triangle," which includes large portions of south and southeast Asia, the Asian Pacific Rim, and northern Australia, is home to scrub typhus, an acute febrile illness [1].
Having a population of more over a billion. The obligatory intracellular Gram-negative bacteria Orientia tsutsugamushi, which was once included in the Rickettsia genus, is responsible for this illness [2]. Scrub typhus is likely one of the most underdiagnosed and underreported febrile illnesses, according to WHO in 1999 [3]. Scrub typhus affects one million people annually, has a 10% mortality rate when untreated, and can be more deadly than dengue [4]. The trombiculid mite (chigger) larvae of the Leptotrombidium genus, which generally feed on wild rats, bite individuals and transmit the illness. [5] The most frequent first symptom is fever, which is frequently accompanied by headache, myalgia, nausea, coughing, and dyspnea. [6-7] In a very variable number of persons, an eschar at the site of inoculation can be discovered if extensively sought for. [8]  If the infection is not immediately recognised and properly treated, it can range from a self-limiting condition to a deadly illness with multiorgan failure in 35–50% of patients [9]. Lower Assam consists of 7 districts namely barpeta, bajali, Bongaigaon, Dhubri, Goalpara, Nalbari and South Salmara. Scrub typhus was first reported in Assam during World War II (1944–1945), on the Myanmar–India border.

Method

Hospital based observational study carried out over a period of 6 months (January 2022 – June 2022). Study enrolled 80 seropositive scrub typhus patients. Diagnosis of scrub typhus was based on case history, clinical examination, rapid immunochromatographic test to identify antibodies against scrub typhus, complete blood count, liver function and renal function test, serum electrolytes, urine routine examination, chest xray, ultra sound of whole abdomen and CT brain, CSF analysis (for patients presenting with altered sensorium).

Results

Among the 80 seropositive patients, 35 patients were male and 45 patients were female, 17.5 % patients were agriculture worker by occupation.  Most common symptoms were fever, nausea, vomiting, headache, myalgia, cough, pain abdomen and puffiness of face.  Eschar was clinically evident in 13.5% of the cases only.  The average duration of symptoms before admission was 7 days.  In patients with severe disease or multi organ system involvement clinical signs such as dyspnea, cough, low blood pressure (MAP ≤ 65 mmHg). The laboratory parameters showed 62.5% patients had elevated total blood count, 25% of patients had low platelet count, 52% of patients had deranged liver function test and 23% of patients had deranged renal function test. The organ system dysfunction, renal failure is the most common followed by hepatitis, CNS dysfunction and ARDS. Out of 80 patients 22 patients required ICU admission and 12 patients were dead. Mortality rate was 22%.

Figure 1 : Symptoms of patients presenting with scrub typhus

Figure 2 : Laboratory paramters of patiens with scrub typhus

Discussion

The overall mortality rate in our study was 22% which was slightly higher when compared to a study done in south India by Varghese et al. which had 14 % mortality rate [10].  The slight increase in the mortality rate might be due to delayed presentation and late referral from periphery centre.  Although eschar was the specific manifestation of the disease only 13.5% of study population had the presentation and is rarely seen in south east Asia population [7,10,11]. The occupation and scrub vegetation’s surrounding the house of the patients are known to have a strong association with acquisition of the infection [12]. In this study we found that 17.5% of study population were agricultural workers and 35% of females were housewives by occupation. Pulmonary dysfunction was the most common complication 30%, and the majority of these patients 55% required invasive ventilator support. Previous studies from India have shown an incidence of ARDS of 8–10% [7,13]. Acute renal failure was seen in 38.7% of our patients. This incidence of renal impairment is higher than the 23.2% incidence reported by Attur et al [14]. The finding of hepatitis in 31.5% and thrombocytopenia was also noted in similar percentages of patients as in previous studies. [15] Based on our observation a severity index score containing 5 parameters were made S- Spo2 ≤ 92% in room air, C – CRP > 20, R – Respiratory rate, U – Urine output, B – Systolic Blood Pressure < 90 mm Hg [SCRUB Index].  SCRUB index ≥ 2 required immediate hospitalization and SCRUB index < 2 can be discharged and treated on outpatient basis. The gold standard criteria was similar in defining the severity of scrub typhus as used in the Thailand study [15,16]. Treatment of scrub typhus was initiated with doxycycline either injectable or oral combination of doxycycline and azithromycin was used in  patients with ARDS & MODS.  Most of the patients responded to doxycycline therapy within 2–3 days except patients who died due to severe MODS and they were referred late to our hospital.  Azithromycin has shown to have comparable efficacy when compared to doxycycline in a small trial. [18] 

Conclusion

Scrub typhus is a severe acute febrile sickness that has a high death rate. Serious life-threatening consequences of this illness include respiratory dysfunction, shock, and abrupt renal failure. To avoid complications that might be fatal, prompt diagnosis, prompt antibiotic medication, and thorough supportive care are essential.

References

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