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Acute Encephalitis Syndrome: A Rare Presentation of Scrub Typhus in Adults

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Virendra Kr Goyal, Jitesh Aggarwal, Manan Dave, Rootik Patel    05 June 2021

ABSTRACT

Scrub typhus or bush typhus or tsutsugamushi disease is a mite-borne acute febrile illness caused by Gram-negative intracellular organism Orientiatsutsugamushi (which belongs to the family of Rickettsiaceae). Common presentation of scrub typhus includes fever, headache and inoculation eschar and lymphadenopathy. In severe forms, pneumonia, myocarditis, azotemia, shock, gastrointestinal bleeding and meningoencephalitis are known to occur. Central nervous system (CNS) involvement may be a complication of scrub typhus, which ranges from meningitis to frank meningoencephalitis. Here we are describing a case of acute encephalitis syndrome (AES), following scrub typhus infection in an adult patient. Patient didn’t have concurrent infection with any other tropical fever diseases, like malaria, chikungunya, typhoid and dengue fever. Patient was put on injection ceftriaxone, capsule doxycycline, tablet azithromycin, tablet levetiracetam and symptomatic treatment with multivitamin support. By Day 3, patient’s sensorium improved and he started to follow verbal commands. Patient was hospitalized in our tertiary care medical college and hospital (AIIMS, Udaipur) for 7 days and recovered completely.

Introduction

Scrub typhus or bush typhus or tsutsugamushi disease is a mite-borne acute febrile illness caused by Gram-negative intracellular organism, Orientiatsutsugamushi (which belongs to the family of Rickettsiaceae). Although the disease has a worldwide distribution, most of the cases are reported from the so-called “tsutsugamushi triangle”, which is a wide area bounded by Pakistan, India, Nepal in the West; Siberia, Japan, China and Korea in the North and Indonesia, Philippines, Australia and the Pacific Islands in the South and is mostly related to agriculture and outdoor activities. There is an estimated 1 million new scrub typhus infections each year and over 1 billion people around the world are at risk of this potentially fatal tropical illness.

It is a common, zoonotic disease in South-East Asia and on account of rapid urbanization of rural and forested areas, it is becoming increasingly common in India.Common presentation of scrub typhus includes fever, headache and inoculation eschar and lymphadenopathy. In severe forms, pneumonia, myocarditis, azotemia, shock, gastrointestinal bleeding and meningoencephalitis may occur.Central nervous system (CNS) involvement may be a complication of scrub typhus which ranges from meningitis to frank meningoencephalitis.The name “typhus” itself, is derived from the Greek word “typhos”, which means stupor. Other neurological complications include seizure, cranial nerve deficits, vasculitic cerebral infarct, brain hemorrhages, polyneuropathy, sensorineural hearing loss, meningitis or meningoencephalitis. Here we are describing a case of acute encephalitis syndrome (AES), following scrub typhus infection in an adult patient. The patient did not have concurrent infection with any other tropical fever diseases, like malaria, chikungunya, typhoid and dengue fever.

CASE SUMMARY

A 25-year-old male resident of Southern Rajasthan presented in our hospital with complaints of fever with chills and rigors for 7 days, decreased appetite and altered sensorium, unable to speak for 2 days and involuntary movements of all four limbs with frothing from the mouth and up rolling of eye balls. On examination, patient was running a high-grade temperature of 101.4°F. Blood pressure 90/80 mmHg in supine position, pulse 120/min, SpO2 98%. Patient was unconscious, disoriented with time, place and person. Patient was not following any verbal commands. For these complaints, patient was admitted in medical intensive care unit (MICU) in our hospital. On general physical examination of the patient, eschar was found (Fig. 1). Tongue bite was present. CNS examination: Higher mental functions and cranial nerve examination could not be accessed. Pupils were normally reacting to light. There were no signs of increased intracranial pressure (ICP). Neck rigidity and hypertonia were present. Bilateral plantar were extensor. Other systems didn’t show any abnormality. There was no organomegaly on per abdomen examination. Fundus examination of the patient suggested no signs of papilledema and increased ICP. Noncontrast computed tomography (NCCT) head was done to rule out hydrocephalus, and it was normal. Magnetic resonance imaging (MRI) brain could not be done due to institutional constraints. Lumbar puncture was done under aseptic precautions and cerebrospinal fluid (CSF) fluid was sent for cytological and biochemical analysis. On gross examination, CSF was drained with normal pressure and was found clear. CSF was found acellular, with proteins 22 mg/dL, sugar 66.8 mg/dL. Corresponding blood sugar was 122 mg/dL. Gram stain and Ziehl-Neelsen staining of CSF fluid was negative. X-ray chest (PA view) of the patient was normal. Complete blood count (CBC) showed mild thrombocytopenia (hemoglobin [Hb]: 13.5, white blood cell [WBC]: 5.63, platelet: 62,000) with mild derangement of liver enzymes with serum glutamic pyruvic transaminase (SGPT): 104.9, serum glutamic oxaloacetic transaminase (SGOT): 78.9. MP QBC, immunoglobulin (IgM/IgG) dengue and NS1 antigen to rule out dengue and IGM typhidot to rule out typhoid fever and enzyme-linked immunosorbent assay (ELISA) test for chikungunya of the patient were negative.

Figure 1. Eschar at left knee.

Ultrasonography of abdomen revealed biliary sludge and moderate splenomegaly (Fig. 2). ELISA test to detect IgM antibodies against O. tsutsugamushiantigens for scrub typhus was found positive. Patient was put on injection ceftriaxone, capsule doxycycline, tablet azithromycin, tablet levetiracetam and symptomatic treatment with multivitamin supports. By Day 3, patient’s sensorium improved and he started to follow verbal commands. He was hospitalized in our tertiary care medical college and hospital for 7 days and recovered completely.

Figure 2. Ultrasonography of the abdomen indicating the presence of biliary sludge in gallbladder.

DISCUSSION

Scrub typhus is a potentially fatal infection, affecting nearly 1 million people each year. The disease first gained significance during the World War II. Several from the US, Ceylon and Burma armies were infected and succumbed to the illness due to lack of proper antibiotic treatment.

Several epidemics of scrub typhus have occurred in India, yet, the literature is still limited. O. tsutsugamushi is known to cause this disease and was first identified and studied in Japan in 1930. An obligate intracellular bacterium, it is transmitted to humans by the bite of larval mites (chiggers) of Leptotrombidiumdeliense. The incubation period is 6-21 days with an average of 10 days. The larval mites usually feed on wild rats. There are several serotypes of O. tsutsugamushi, and infection with one species provides only transient cross immunity to another. When a forest is cleared, scrubs tend to grow on those areas. These scrubs later get infested by larval mites. When man comes in contact with these scrubs, he contracts the infection. The basic pathologic changes include focal vasculitis and perivasculitis of small blood vessels in the involved organs. These occur as a result of multiplication of the organism in the endothelial cells lining the small blood vessels. 

Acute encephalitis syndrome is characterized by rapid onset of febrile illness associated with convulsions, altered sensorium and focal neurological deficit such as aphasia, hemiparesis, involuntary movements, ataxia or cranial nerve involvement. In a study conducted in India, on acute febrile encephalopathy including 120 patients, the common causes included acute viral encephalitis, pyogenic meningitis, tuberculous meningitis, cerebral malaria and sepsis related encephalopathy. On the contrary, in our case, the etiology was scrub typhus. This unusual presentation of scrub typhus can be easily overlooked (in this COVID era), resulting in delay in initiating life-saving treatment.

CONCLUSION

Acute encephalitis syndrome is not an uncommon neurological presentation following scrub typhus infection in adults. It should be suspected in all patients with fever, altered sensorium and hepatic involvement. Oral azithromycin can be started as soon as possible for better outcomes.

SUGGESTED READING

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