Status epilepticus in scrub typhus

Neurological Manifestations of Scrub Typhus

PURPOSE OF REVIEW

The occurrence of cases of scrub typhus is on the rise in South Asian and Southeast Asian countries. The present review discusses neurological complications following scrub typhus to appraise clinicians practicing in endemic regions about considering this treatable disease in the differential diagnosis of acute febrile illnesses, especially when accompanied with clinical neurological features.

RECENT FINDINGS

While the association of aseptic meningitis, encephalitis, and meningoencephalitis with scrub typhus is well known, more recently described neurological syndromes associated with scrub typhus include acute disseminated encephalomyelitis, various cranial nerve palsies, cerebellitis, cerebrovascular diseases including cerebral venous sinus thrombosis, transverse myelitis, longitudinally extensive transverse myelitis, Guillain-Barré syndrome, opsoclonus-myoclonus syndrome, parkinsonism, and many more. Early diagnosis is key to successful treatment. While diagnostic confirmation is generally made by the detection of IgM antibody by either ELISA or indirect fluorescent antibody tests, conventional PCR using 56 kDa gene (cPCR) and loop-mediated isothermal amplification assay (LAMP assay), as well as a newly introduced metagenomic next-generation sequencing (mNGS), are currently available for detection of Orientia tsutsugamushi infection in clinically suspected cases. Scrub typhus is an acute febrile illness caused by Orientia tsutsugamushi. The cutaneous hallmark of the disease is the "eschar." Scrub typhus results in multisystem involvement. Neurological compromise is present in about 20% of scrub typhus patients and affects both the central nervous system and the peripheral nervous system. The postulated underlying mechanisms include direct invasion of the organism, a vasculitis-like process, or an immune-mediated injury. Diagnosis of scrub typhus is confirmed by detection of O. tsutsugamushi IgM antibody in serum. Awareness among clinicians regarding the varied presentations of this disease is very important in order to reduce morbidity and mortality. Co-infection with dengue and/or chickungunya viruses may occur in endemic regions. The history of an acute febrile illness preceding the neurological illness is crucial. A very careful search for the eschar is essential; however, the absence of the skin lesion cannot exclude the diagnosis of scrub typhus. Neurological manifestations mostly respond to doxycycline therapy.

Systematic review of the scrub typhus treatment landscape: Assessing the feasibility of an individual participant-level data (IPD) platform

Background

Scrub typhus is an acute febrile illness caused by intracellular bacteria from the genus Orientia. It is estimated that one billion people are at risk, with one million cases annually mainly affecting rural areas in Asia-Oceania. Relative to its burden, scrub typhus is understudied, and treatment recommendations vary with poor evidence base. These knowledge gaps could be addressed by establishing an individual participant-level data (IPD) platform, which would enable pooled, more detailed and statistically powered analyses to be conducted. This study aims to assess the characteristics of scrub typhus treatment studies and explore the feasibility and potential value of developing a scrub typhus IPD platform to address unanswered research questions.

Methodology/principal findings

We conducted a systematic literature review looking for prospective scrub typhus clinical treatment studies published from 1998 to 2020. Six electronic databases (Ovid Embase, Ovid Medline, Ovid Global Health, Cochrane Library, Scopus, Global Index Medicus), ClinicalTrials.gov, and WHO ICTRP were searched. We extracted data on study design, treatment tested, patient characteristics, diagnostic methods, geographical location, outcome measures, and statistical methodology.

Among 3,100 articles screened, 127 were included in the analysis. 12,079 participants from 12 countries were enrolled in the identified studies. ELISA, PCR, and eschar presence were the most commonly used diagnostic methods. Doxycycline, azithromycin, and chloramphenicol were the most commonly administered antibiotics. Mortality, complications, adverse events, and clinical response were assessed in most studies. There was substantial heterogeneity in the diagnostic methods used, treatment administered (including dosing and duration), and outcome assessed across studies. There were few interventional studies and limited data collected on specific groups such as children and pregnant women.

Conclusions/significance

There were a limited number of interventional trials, highlighting that scrub typhus remains a neglected disease. The heterogeneous nature of the available data reflects the absence of consensus in treatment and research methodologies and poses a significant barrier to aggregating information across available published data without access to the underlying IPD. There is likely to be a substantial amount of data available to address knowledge gaps. Therefore, there is value for an IPD platform that will facilitate pooling and harmonisation of currently scattered data and enable in-depth investigation of priority research questions that can, ultimately, inform clinical practice and improve health outcomes for scrub typhus patients.

Scrub typhus is a febrile illness most commonly found in rural tropical areas. It is caused by a Gram-negative bacteria belonging to the family Rickettsiaceae and transmitted by mites when they feed on vertebrates. There is an estimate of one million cases annually, with an estimated one billion people at risk, mostly in Asia-Oceania. But relative to the scale of the problem, scrub typhus is largely understudied. Evidence-based treatment recommendations by policymakers vary or are non-existent. We searched databases and registries for prospective scrub typhus clinical treatment studies published from 1998 to 2020 and reviewed them. Data from clinical trials and particularly for specific groups, such as pregnant women and children, were minimal. The methods used to measure treatment efficacy were heterogeneous, making it difficult to directly compare or conduct a meta-analysis based on aggregated data. One way to improve the current level of evidence would be by pooling and analysing individual participant-level data (IPD), i.e. the raw data from individual participants in completed studies. This review demonstrated that there is scope for developing a database for individual participant data to enable more detailed analyses. IPD meta-analyses could be a way to address knowledge gaps such as optimum dosing for children and pregnant women.

Prolonged coma in scrub typhus: consider non-convulsive status epilepticus

BACKGROUND

Scrub typhus is prevalent in the Tsutsugamushi belt and may manifest with meningoencephalitis and seizures. We report a patient with scrub typhus who had non-convulsive status epilepticus (NCSE).

METHODS

A 50-y-old female with fever and altered sensorium for 5 d was diagnosed as scrub typhus based on serum IgM ELISA. She was on mechanical ventilation and received doxycycline and ceftriaxone, but did not improve until the third day of admission.

RESULTS

An EEG revealed >2.5 Hz generalised epileptiform discharges, which were suppressed by intravenous lorazepam suggesting NCSE. Following valproate and levetiracetam, she became conscious and had a full recovery.

CONCLUSION

A scrub typhus patient recovers even after prolonged NCSE.

Neurological facets of scrub typhus: A comprehensive narrative review

Scrub typhus is one of the most frequent causes of acute febrile illness in South and South-east Asian countries. Neurological features accompany 20% of scrub typhus infections, and may affect the central or peripheral nervous system, and sometime, may even occur in combination. Of late, its recognition among clinicians has increased with widening detection of its cutaneous hallmark, called eschar. Multiple mechanisms underlie neurological involvement, including direct invasion (meningitis, encephalitis), vasculitis (myositis) or immune-mediated mechanisms (opsoclonus, myoclonus, optic neuritis, Guillain–Barre syndrome). Despite an immunological basis for several neurological manifestations, response to doxycycline is remarkable, although immune therapy may be necessary for severe involvement. Scientific literature on scrub typhus neurology chiefly emanates from case reports, case series and small studies, and a comprehensive review is warranted to aid clinicians in recognising neurological involvement. This review aims at enriching this gap, and summarises clinical features, laboratory findings, and treatment options for various neurological facets of scrub typhus.

Haemorrhagic encephalitis in the garb of scrub typhus

A 19-year-old girl presented with fever, headache, vomiting and drowsiness. She had grade 1 papilloedema and neck rigidity but no focal deficits or seizures. Cerebrospinal fluid analysis revealed lymphocytic pleocytosis, slightly elevated protein and normal glucose. MRI of the brain showed a hyperintense lesion in left ganglio-capsular region on the fluid attenuation inversion recovery sequence with perilesional oedema and mild midline shift. Haemorrhage was seen in the region on susceptibility weighted imaging . The patient was thoroughly investigated for known causes of meningoencephalitis, but the diagnosis of scrub typhus was delayed till the 10th day of illness. She was treated with doxycycline for 2 weeks and had marked improvement, both clinically and radiologically. Literature review has revealed that although meningoencephalitis in scrub typhus is not uncommon, such atypical lesions on brain MRI are a rarity. Serial imaging was performed to document the disease progression and resolution on treatment.

Acute transverse myelitis following scrub typhus: A case report and review of the literature

Context: Scrub typhus is an acute febrile disease caused by Orientia tsutsugamushi. The disease can usually involve the lungs, heart, liver, spleen and brain through hematogenous dissemination. However, very rarely, acute transverse myelitis in the spinal cord develops from scrub typhus. We present a case of acute transverse myelitis following scrub typhus with a review of the literature. Findings: A 66-year-old male visited a hospital for general myalgia, mild headache, and fever in October. He was noted to have thick, black papule skin on his abdomen, which was highly suggestive of scrub typhus. To confirm the diagnosis, O. tsutsugamushi antibody titers were examined and detected highly in serum by an indirect fluorescence antibody assay. Doxycycline, the standard treatment for scrub typhus, was administered. However, after seven days of treatment, he rapidly developed weakness in the right leg, paresthesia in both lower limbs, and voiding difficulty. Spinal magnetic resonance imaging (MRI) revealed lesions with high signal intensity involving the spinal cord at the thoracolumbar junction. Paraparesis gradually improved following steroid pulse therapy for five days. At one-year follow-up, he could walk without cane. Conclusions:Orientia tsutsugamushi causes scrub typhus, which can affect not only the brain, but also the spinal cord. Although acute transverse myelitis develops rarely from scrub typhus, this should be considered as differential diagnosis in patients of fever with neurological deficit in endemic areas.

Clinical Profile of Scrub Typhus Meningoencephalitis among South Indian Children

Re-emerging scrub typhus is gaining recognition as an important cause of paediatric meningoencephalitis in tropics. We studied the clinical profile of scrub typhus meningoencephalitis (STME) in children <12 years. Of 270 serology-confirmed cases of scrub typhus, 14 (5%) had features consistent with STME and 9 (64%) of these children were between 5 and 12 years of age; 12 (85%) children presented to the hospital during the second week of illness. Fever, headache and altered sensorium were observed in all children, while meningeal signs, papilledema and seizures were observed in 8 (57%), 7 (50%) and 6 (43%) children, respectively. The mean CSF protein level, glucose level, cell count and percentage of lymphocytes were 75 mg/dl, 46 mg/dl, 41 cells and 86%, respectively. STME should be considered in febrile children from endemic area with neurological features, such as headache or altered sensorium. Lumbar puncture is mandatory to confirm STME and rule out close differential diagnosis, such as pyogenic and tubercular meningitis.

Central Nervous System Infection Associated with Orientia tsutsugamushi in South Korea

Orientia tsutsugamushi is a major cause of vector-borne infection in Asia. Prompt recognition and appropriate treatment are crucial because of its potentially fatal complications and lack of response to beta-lactam antibiotics. The present study retrospectively evaluated the clinical characteristics and laboratory findings of 16 patients with scrub typhus-related central nervous system (CNS) infections. Single titers ≥ 1:40 of total serum antibodies against O. tsutsugamushi detected by an indirect immunofluorescent assay were considered as positive results. The median age was 35.5 (range, 14-72) years, and 10 (62.5%) patients were female. The most common symptoms were headache (81.3%) and fever (81.3%). Eschar formation was found in three (18.8%) patients. Among patients with encephalitis, seizures and altered consciousness occurred in five (83.3%) and four (66.7%) patients, respectively. An abnormal liver function was noted in seven (43.8%) patients. The median antibody titer was 1:120 (range, 1:40-1:2,560). Typical cerebrospinal fluid profiles were lymphocytic pleocytosis, mild protein elevations, and normal glucose levels. All patients received an empirical treatment with doxycycline and most (93.8%) of them recovered without neurological sequelae. None of the patients reported side effects of the doxycycline treatment. An empirical treatment with doxycycline is needed in patients with CNS infections in scrub typhus endemic areas.