|Year : 2022 | Volume
| Issue : 3 | Page : 101-103
Scrub Typhus Meningoencephalitis: An Uncommon Cause of Acute Febrile Encephalopathy in the Elderly
Lekshmi V Kesavan Nair1, Rajani K Timmalsugur2, Vishal Mangal1
1 Department of Internal Medicine, Armed Forces Medical College, Pune, Maharashtra, India
2 Department of Internal Medicine, Command Hospital (Southern Command), Pune, Maharashtra, India
|Date of Submission||10-Dec-2020|
|Date of Acceptance||22-Feb-2021|
|Date of Web Publication||21-Jan-2022|
Dr. Lt Col Vishal Mangal
Department of Internal Medicine, Armed Forces Medical College, Pune - 411 040, Maharashtra
Source of Support: None, Conflict of Interest: None
Central nervous system infections are an uncommon cause of acute febrile encephalopathy (AFE) in the elderly. Scrub typhus meningoencephalitis is uncommon and often missed in the elderly. A 70-year-old male presented with complaints of intermittent fever, maculopapular rash, and altered sensorium. Physical examination revealed fever, tachycardia, tachypnea, maculopapular rash on the trunk, and all four limbs, and an eschar on the right thigh. Initial laboratory evaluation revealed anemia, thrombocytopenia, and azotemia. The cerebrospinal fluid revealed lymphocytic pleocytosis, elevated proteins with normal glucose, and adenosine deaminase. Weil–Felix test was positive. The diagnosis of scrub typhus meningoencephalitis with acute kidney injury and atypical pneumonia was established. A prompt treatment with injection doxycycline and tablet rifampicin led to an uneventful recovery. We report the first case of scrub typhus meningoencephalitis as the cause of AFE in the elderly. This case highlights the importance of clinical examination in any febrile encephalopathy presenting in endemic areas or travelers returning from such places.
Keywords: Acute febrile encephalopathy, case report, elderly, meningoencephalitis, scrub typhus
|How to cite this article:|
Kesavan Nair LV, Timmalsugur RK, Mangal V. Scrub Typhus Meningoencephalitis: An Uncommon Cause of Acute Febrile Encephalopathy in the Elderly. J Mar Med Soc 2022;24, Suppl S1:101-3
| Introduction|| |
Scrub typhus is common in India; however, statistics on prevalence, morbidity, and mortality are not available. It is caused by Orientia tsutsugamushi and is characterized by fever, an eschar, lymphadenopathy, and multisystem involvement and usually responds well to doxycycline. In India, the first reported cases were in Himachal Pradesh in 1934. The larval forms of trombiculid mite transmit the disease to humans. The rodents are the natural hosts; however, humans get infected accidentally following the bites of chiggers. The infection spreads through both hematogenous and lymphatic routes. Chills and fever occur by the 3rd–4th day of the bite, and rash and lymphadenopathy appear at the end of the 1st week. The incubation period ranges from 6 to 20 days. Serious complications occur during the 2nd week of illness and comprise pneumonia, hepatitis, acute kidney injury (AKI), acute respiratory distress syndrome, and meningitis. Acute febrile encephalopathy (AFE) is defined as the coexistence of fever and altered mental status in the form of confusion, behavioral changes, disorientation, or other cognitive impairments. The most common cause of AFE in the elderly (age >65 years) is sepsis-associated encephalopathy due to noncentral nervous system (CNS) infections. The most common pathogens associated with CNS infection in AFE in the elderly are Streptococcus pneumoniae, Mycobacterium tuberculosis, Brucella species, herpes virus, Staphylococcus aureus, Pseudomonas species, and Acinetobacter species. Scrub typhus has rarely been reported as a cause of AFE in the elderly. Here, we report such a case of AFE in the elderly who presented early with multisystem involvement and recovered fully with conventional therapy despite being in a high-risk mortality group.
| Case Report|| |
A 70-year-old male farmer, with a past medical history of ischemic posterior circulation stroke in 2013 with complete recovery, presented with complaints of intermittent fever with chills and rigors and a maculopapular rash over the trunk of 5-day duration. He also had an altered sensorium of 3-day duration with no headache, vomiting, seizures, or focal neurological deficits. Physical examination revealed fever, tachycardia, disproportionate tachypnea, maculopapular rash on the trunk, and all four limbs, and an eschar on the right thigh [Figure 1]. He did not have evidence of meningism. He had hypoactive delirium and fine bilateral crackles with hypoxemic respiratory failure indicating probable atypical pneumonia. Initial laboratory evaluation revealed anemia, thrombocytopenia, and azotemia [Table 1]. The cerebrospinal fluid (CSF) revealed lymphocytic pleocytosis, elevated proteins with normal glucose, and adenosine deaminase (ADA). He also underwent magnetic resonance imaging of the brain because of AFE [Table 2]. He was evaluated for all the possible tropical infections; however, the Weil–Felix test was positive. He was diagnosed as a case of scrub typhus with meningoencephalitis, AKI, and probable atypical pneumonia and was managed with injection doxycycline intravenous 100 mg twice daily and oral rifampicin 600 mg once a day for 7 days, along with supportive care. The fever and altered sensorium resolved over 2 days, and he was discharged in a stable condition after 10 days.
|Figure 1: The red arrow shows the eschar over the medial aspect of the right thigh|
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| Discussion|| |
The decline in the immune system's capability with age is responsible for the increased susceptibility of aging individuals to infection. Confusion, which is the predominant feature of encephalopathy, is present in up to 50% of elderly hospitalized patients. When confusion is accompanied by fever, the first thing which comes to mind is the possibility of CNS infection; however only 7.4 % of the patients have CNS infection who present with AFE. Scrub typhus meningoencephalitis is an uncommon cause of AFE in the elderly and is very difficult to diagnose because the clinical signs such as fever and neck stiffness have low sensitivity. Our patient presented with fever and altered mental status with the absence of neck rigidity; however, he underwent early diagnostic lumbar puncture because of eschar and high clinical suspicion, which helped in establishing the diagnosis.
“Typhus” is derived from the Greek word “Typos” for “fever with stupor” or smoke and refers to the clouded sensorium of patients of severe rickettsioses. The CNS manifestations are varied and include peripheral neuropathy, Guillain–Barre syndrome, acute transverse myelitis, cerebral microbleeds, infarcts due to secondary CNS vasculitis, meningoencephalitis, and cerebellitis. The clinical manifestations of scrub meningoencephalitis are similar to viral or tubercular meningitis. A period of fever is followed after a variable time with encephalopathy. Neck rigidity is not typical, and eschar, the scrub typhus's pathognomic feature, was infrequently seen in various scrub meningoencephalitis studies. Patients can present as early as 3 days of fever and as late as 2 weeks. There is no sexual preponderance. Our patient was an elderly male farmer who presented with a short duration of fever (5 days) and encephalopathy. He did not have neck stiffness; however, an eschar was present. CSF analysis is always lymphocytic predominant with elevated protein, normal glucose, and ADA levels. CSF polymerase chain reaction is a confirmative test to diagnose scrub meningoencephalitis. However, serum scrub immunoglobulin M ELISA is readily available, and hence, the confirmation of scrub typhus in the setting of clinical features of meningoencephalitis can be done by this method, especially in resource-poor settings. The CSF picture was consistent with the observed analysis in previous studies, and the final diagnosis was made by clinical findings and serology as has been advised in resource constraint settings. The treatment of choice is oral or injectable doxycycline 100 mg twice a day for 1–2 weeks. In a pregnant woman, azithromycin is the drug of choice. In case of inadequate response to doxycycline, chloramphenicol, or rifampicin may be used for treatment. Rifampicin should be used in combination, either with azithromycin or doxycycline, to prevent resistance development. The use of rifampicin in areas with high TB incidence is not routinely recommended. Written informed consent was obtained from the patient to publish the case report.
| Conclusion|| |
CNS infection as a cause of AFE in the elderly is uncommon. However, detailed clinical examination can help in establishing the correct diagnosis. Scrub typhus is commonly seen in endemic areas, however, clinicians need to have high index of suspicion, especially in the elderly presenting with AFE.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]