Scrub typhus meningo-encephalitis with focal neurologic signs and associated brain MRI abnormal findings: literature review

Scrub Typhus Masquerading as Limbic Encephalitis

Scrub typhus, an acute febrile infectious disease prevalent in the 'tsutsugamushi triangle', is a mite-born rickettsial zoonosis, caused by Orientia tsutsugamushi. The clinical presentation is protean and involves multiple organ systems of the body, including central and peripheral nervous systems. We report a 22-year-old previously healthy Indian woman who presented with clinical (confusion, excessive sleepiness, cognitive dysfunction and focal seizures) and neuroimaging features of limbic encephalitis. After exclusion of common infectious, autoimmune and paraneoplastic causes, she was diagnosed with scrub typhus associated encephalitis, which responded to doxycycline and azithromycin therapy.

Establishment of a Rhesus Macaque Model for Scrub Typhus Transmission: Pilot Study to Evaluate the Minimal Orientia tsutsugamushi Transmission Time by Leptotrombidium chiangraiensis Chiggers

Recently, an intradermal inoculation of the rhesus macaque model of scrub typhus has been characterized at our institution. The current project was to establish a rhesus macaque model of scrub typhus using the naturally infected chigger challenge method that faithfully mimics the natural route of pathogen transmission to fully understand the host-pathogen-vector interactions influencing pathogen transmission. Unlike the needle-based inoculation route, Orientia tsutsugamushi-infected chiggers introduce both pathogen and chigger saliva into the host epidermis at the bite site. However, information on the interaction or influence of chigger saliva on pathogenesis and immunity of host has been limited, consequently hindering vaccine development and transmission-blocking studies. To characterize chigger inoculated O. tsutsugamushi in rhesus macaques, we determined the minimum chigger attachment time required to efficiently transmit O. tsutsugamushi to the immunocompetent hosts and preliminary assessed clinical parameters, course of bacterial infection, and host’s immunological response to identifying potential factors influencing pathogen infection. Chigger infestation on hosts resulted in: (i) Rapid transmission of O. tsutsugamushi within 1 h and (ii) antigen-specific type I and II T-cell responses were markedly increased during the acute phase of infection, suggesting that both systems play critical roles in response to the pathogen control during the primary infection. In summary, we demonstrate that O. tsutsugamushi infection in rhesus macaques via chigger challenge recapitulates the time of disease onset and bacteremia observed in scrub typhus patients. Levels of proinflammatory cytokines and chemokines were positively correlated with bacteremia.

Association between scrub typhus encephalitis and diffusion tensor tractography detection of Papez circuit injury: A case report

BACKGROUND

It is difficult to restore the cognitive functions of patients with impaired cognition caused by brain injury. Diffusion tensor imaging can visualize the integrity of neural tracts in the white matter (WM) three-dimensionally. It is unclear whether encephalitis following scrub typhus damages the WM. For the first time, we aimed to report diffusion tensor tractography (DTT) findings in a chronic patient with cognitive impairment following scrub typhus encephalitis, which revealed injury to the Papez circuit of the WM.

CASE SUMMARY

A 70-year-old male patient was affected by encephalitis caused by scrub typhus that occurred 23 years ago. He had poor cognition and his clinical examination findings were as follows: Mini-Mental Status Examination score, 14; and handgrip strength (right/left, kg), 32.3/31.3. DTT revealed serious injuries of the left thalamocingulate tract and right mammillothalamic tract in the Papez circuit, and a partial injury of the anterior part of the fornix.

CONCLUSION

Using DTT, we found a relationship between cognitive impairment and the integrity of the Papez circuit following scrub typhus.

Diffusion tensor imaging analysis in scrub typhus meningoencephalitis to determine the alteration of microstructural subcortical white-matter integrity

BACKGROUND AND PURPOSE

Magnetic resonance imaging (MRI) of the brain in scrub typhus meningoencephalitis is non-specific, and in the majority of the cases, conventional MRI fails to detect any abnormality. However, autopsy reports depict central nervous system involvement in almost all patients. There is therefore a need for research on the quantitative assessment of brain parenchyma that can detect microstructural abnormalities. The study aimed to assess the microstructural integrity changes of scrub typhus meningoencephalitis by using different diffusion tensor imaging (DTI) parameters.

METHODS

This was a retrospective analysis of scrub typhus meningoencephalitis. Seven patients and seven age- and sex-matched healthy controls were included. Different DTI parameters such as apparent diffusion coefficient (ADC), fractional anisotropy (FA), relative anisotropy (RA), trace, volume ratio (VR) and geodesic anisotropy (GA) were obtained from six different regions of subcortical white matter at the level of the centrum semiovale. Intergroup significant difference was determined by one-way analysis of variance followed by Tukey's post hoc test. Receiver operating characteristic curves were constructed to determine the accuracy of the DTI matrices.

RESULTS

There was a significant decrease in FA, RA and GA as well as an increase in ADC and VR in the subcortical white matter in patients with scrub typhus meningoencephalitis compared to controls (p < 0.001). The maximum sensitivity of the DTI parameters was 85.7%, and the maximum specificity was 81%.

CONCLUSION

There was an alteration of subcortical white-matter integrity in scrub typhus meningoencephalitis that represents the axonal degeneration, myelin breakdown and neuronal degeneration. DTI may be a useful tool to detect white-matter abnormalities in scrub typhus meningoencephalitis in clinical practice, particularly in patients with negative conventional MRI.

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.

Chronic encephalopathy and locked-in state due to scrub typhus related CNS vasculitis

BACKGROUND

Scrub Typhus, prevalent in Asia-Pacific region, often has neurological manifestations in the setting of acute febrile illness, as acute encephalitis syndrome.

CASE REPORT

A 20-year-old female, from western Rajasthan, India presented with calf pain followed by nausea, vomiting, dizziness, and sequentially progressive weakness of limbs, anarthria and loss of bladder control over 10 days. MRI Brain showed T2-weighted and FLAIR hyperintense lesions in corpus callosum, subcortical and periventricular white matter, basal ganglia, thalamus, brainstem and cerebellum producing starry sky appearance with diffusion restriction. Serum IgM for Scrub typhus was positive and patient progressively improved over 3 weeks with doxycycline.

CONCLUSIONS

This report highlights an unusual presentation of scrub typhus with subacute onset and static course, quadriparesis and locked-in state for 2 months, suspected based on red flags on neuroimaging and reversal of deficits with appropriate treatment.

Prolonged coma in a scrub typhus patient

Central nervous system symptoms occur in more than 80% of patients with scrub typhus infection; however, the entity of central nervous system involvement is still not fully understood. We present the case of a patient with fulminant scrub typhus with multiple organ failure, including prolonged deep coma, and detail the sequential neurological symptoms, signs, laboratory data, and neuroradiological findings.

Clinical manifestations of scrub typhus

The mite-borne rickettsial zoonosis scrub typhus is widely prevalent in parts of Southeast and Far East Asia, and northern Australia. The disease is an acute febrile illness, associated with rash and often an eschar, which responds dramatically to treatment with antibiotics. In some cases it results in a serious illness leading to multiple organ involvement and death. The disease manifestations are thought to result from a systemic vasculitis, caused by both direct effects of the organisms as well as an exaggerated immune response, although little is understood about its pathogenesis. A wide spectrum of clinical manifestations, affecting nearly every organ system, have been described with scrub typhus. Some of these manifestations are serious and life threatening. In this systematic review, we summarise the typical and atypical manifestations of scrub typhus reported in the literature. Awareness of these unusual manifestations will hopefully guide clinicians towards diagnosing the condition early, and initiating early appropriate antibiotics and other supportive measures.

Differential diagnosis of scrub typhus meningitis from tuberculous meningitis using clinical and laboratory features

OBJECTIVES

The involvement of the central nervous system in the form of meningitis or meningoencephalitis is common in scrub typhus and is an important differential diagnosis of other lymphocytic meningitis like tuberculous meningitis (TBM). The aim of this study was to identify the clinical and laboratory parameters that may be helpful in differentiating scrub typhus meningitis from TBM.

PATIENTS AND METHODS

We compared of the clinical and laboratory features of 57 patients admitted with scrub typhus meningitis or TBM during a 3-year period. Patients who had abnormal cerebrospinal fluid (CSF) and positive scrub typhus enzyme-linked immunosorbent assay serology (n=28) were included in the scrub typhus meningitis group, while the TBM group included those who satisfied the consensus diagnostic criteria of TBM (n=29).

RESULTS

Compared with the TBM group, the mean duration of symptoms was less in patients with scrub typhus meningitis, who also had a lower magnitude of neurological deficits, such as altered mental status and cranial nerve and motor deficits. Patients with scrub typhus meningitis had a lower CSF white blood-cell count (WBC) than the TBM group (130.8±213 195±175 cells/mm³, P=0.002), lower CSF protein elevation (125±120 vs. 195.2±108.2mg/dl, P=0.002), and higher CSF sugar (70.1±32.4 vs. 48.7±23.4mg/dl, P=0.006). Features predictive of the diagnosis of scrub typhus meningitis included the absence of neurological impairment at presentation, blood serum glutamic-oxaloacetic transaminase>40 international units (IU)/L, serum glutamic-pyruvic transaminase>60 IU/L, total blood leukocyte count>10,000/mm³, CSF protein<100mg/dl, CSF sugar>50mg/dl, CSF WBC<100 cells/mm³. All patients with scrub typhus meningitis recovered completely following doxycycline therapy CONCLUSIONS: This study suggests that, clinical features, including duration of fever, neurological deficits at presentation and laboratory parameters such as CSF pleocytosis,CSF protein elevation, CSF sugar levels and liver enzyme values are helpful in differentiating scrub typhus meningitis from tuberculous meningits. These features with scrub IgM serology may be helpful in identifying patients with scrub meningitis and in avoiding prolonged empirical antituberculous therapy in cases of lymphocytic meningitis.

A Case of Scrub Typhus Related Encephalopathy Presenting as Rapidly Progressive Dementia

Background

An infection known to be a major cause of mild encephalitis/encephalopathy with a reversible splenial lesion (MERS). Rapidly progressive dementia is a neurological condition in which dementia progresses in a short period of time.

Case Report

We report on a 78-year-old woman presenting with a rapid decline in cognitive function resulting from a scrub typhus infection. Diffusion weighted images showed a signal intensity at the splenium, and subcortical white matter of both hemispheres suggesting MERS. On the neuropsychological test, the patient showed frontal executive dysfunction.

Conclusions

This case suggests that diagnosticians should consider the possibility that a MERS patient with a rapidly cognitive decline could have a scrub typhus infection because early diagnosis of scrub typhus is very important in this aspect of the treatment.

CNS Manifestations in Orientia tsutsugamushi Disease (Scrub Typhus) in North India

OBJECTIVE

To present the clinical, lab profile and outcome of a series of six children who had features of meningoencephalitis (median age of 10.5 y) diagnosed as confirmed scrub typhus (ST) by using a lgM ELISA commercial kit (InBiOS International Inc. USA).

METHODS

This was a prospective observational study conducted at a tertiary care hospital, over a period of 7 mo through April 2014. All the patients with undifferentiated febrile illness (aged 1-18 y) with fever of 5-21 d duration were evaluated. After thorough physical examination they were subjected to blood investigations such as complete blood count (CBC), blood culture, hepatic and kidney function tests, serum electrolytes, cerebrospinal fluid (CSF) analysis and IgM ELISA for scrub typhus, coagulogram and chest radiograph, wherever indicated.

RESULTS

During this period, of the total 81 confirmed cases based on a positive scrub IgM ELISA and/or eschar, 6 (7.4 %), had neurological involvement in the form of presence of neck stiffness, altered sensorium and/or seizures and the CSF findings were suggestive of meningoencephalitis and all had evidence of multiple organ dysfunction syndrome (MODS) needing intensive care. The CECT could be performed in four patients only showing evidence of effacement of sulci and evidence of brain edema.

CONCLUSIONS

This communication highlights that variable central nervous system (CNS) involvement is not uncommon in patients with scrub typhus with high mortality. CSF and neuro-radiology findings are nonspecific as these are also observed in patients with aseptic meningitis or encephalitis. Early suspection and institution of appropriate therapy without delay will lead to substantial reduction in the morbidity and mortality.

Ophthalmoplegia Due to Scrub Typhus

Scrub typhus is an acute febrile infectious disease caused by Orientia tsutsugamushi. The illness is usually characterized by fever, rash, and lymphadenopathy, but severe cases progress to pulmonary and neurological involvement. We report a 69-year-old man who developed ptosis and ophthalmoplegia with a focal nodular lesion in the anterior cavernous sinus detected with magnetic resonance imaging. Found to have scrub typhus, the ptosis and ophthalmoplegia resolved after treatment with doxycycline.

Scrub typhus mimicking Parkinson's disease

Background

Scrub typhus is a re-emerging infection in Sri Lanka. It often poses a diagnostic challenge and tends to present as a febrile illness of uncertain origin. Undiagnosed illness may progress to serious multi-systemic complications. Here we report a case of scrub typhus presenting with features of Parkinsonism.

Case presentation

A 62-year-old previously healthy Sri Lankan native male from the Western province of Sri Lanka presented with high fever with malaise, myalgia and arthralgia for 17 days. On the 5th day of illness he developed intermittent resting tremor in his right arm and leg associated with stiffness, difficulty in carrying out normal work and difficulty in smiling. He denied similar previous episodes. There were no other associated neurological manifestations. Clinical examination revealed a high amplitude low frequency resting tremor in his right hand, a mask-like face and increased muscle tone limited to the right side with normal reflexes. The rest of the system examination was normal except for an eschar over the abdomen. His investigations revealed lymphocytic leukocytosis, high erythrocyte sedimentation rate and immunofluorescence assay-IgM and IgG against Orientia tsutsugamushi Karp antigen were positive with rising titers. With oral doxycycline and azithromycin his fever settled within 48 h and a complete recovery of Parkinson’s features was observed within 2 weeks.

Conclusion

Doctors practicing in endemic regions should be familiar with delayed clinical manifestations of scrub typhus and should carefully look for an eschar in order to avoid delay in the diagnosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1428-x) contains supplementary material, which is available to authorized users.

Neurological manifestations of scrub typhus

OBJECTIVE

To evaluate the neurological manifestations of scrub typhus and correlate their clinical, EEG and MRI findings.

METHODS

A cross-sectional study over 2 years included patients with scrub typhus diagnosed by solid phase immunochromatographic assay or Weil-Felix test. A detailed clinical evaluation including Glasgow Coma Scale (GCS) was documented. Blood counts, chemistry, ECG, chest radiograph, cerebrospinal fluid (CSF), EEG and cranial MRI were performed. Outcome on discharge and at 1 month were categorised into good and poor based on modified Rankin Scale.

RESULTS

Thirty-seven patients with ages ranging between 3 and 71 years were included; 51% of whom were females. All patients had fever and myalgia. Thirty-one (84%) patients had impaired consciousness, and six were deeply comatose (GCS score ≤8). Eight patients presented with status epilepticus. MRI revealed meningeal enhancement in only 1/25 (4%) patient and EEG showed generalised slowing in 6/28 (21.4%). Among 31 patients with altered sensorium, CSF studies were conducted on 28. Nineteen patients had meningoencephalitis and 9 encephalopathy, but no significant differences were observed in clinical, laboratory, EEG and MRI findings. All patients responded within 48 h to doxycycline and had good recovery at 1 month. Patients with low GCS score had significantly more focal neurological deficit (r=0.5; p=0.002), longer hospital stay (r=-0.4; p=0.03) and more disability on discharge (r=-0.4; p=0.01).

CONCLUSIONS

Meningoencephalitis/encephalopathy may be seen in two-third of patients with scrub typhus. Scrub typhus should be included in the differential diagnosis of febrile encephalopathy.

Role of advanced MRI brain sequences in diagnosing neurological complications of scrub typhus

Scrub typhus is a rare disease affecting many organs and causing vasculitis by affecting the endothelium of blood vessels. Review of literature shows that there are only a few case reports describing the neuroradiological manifestations of scrub typhus. This case report describes how newer and advanced MRI sequences are able to diagnose neurological complications of scrub typhus, such as hemorrhages, meningoencephalitis, infarctions, cranial nerve involvement, thrombosis, and hypoperfusion, that are not picked up on routine magnetic resonance imaging (MRI) sequences.

Scrub typhus meningitis in South India--a retrospective study

Background

Scrub typhus is prevalent in India although definite statistics are not available. There has been only one study on scrub typhus meningitis 20 years ago. Most reports of meningitis/meningoencephalitis in scrub typhus are case reports

Methods

A retrospective study done in Pondicherry to extract cases of scrub typhus admitted to hospital between February 2011 and January 2012. Diagnosis was by a combination of any one of the following in a patient with an acute febrile illness- a positive scrub IgM ELISA, Weil-Felix test, and an eschar. Lumbar puncture was performed in patients with headache, nuchal rigidity, altered sensorium or cranial nerve deficits.

Results

Sixty five cases of scrub typhus were found, and 17 (17/65) had meningitis. There were 33 males and 32 females. Thirteen had an eschar. Median cerebrospinal fluid (CSF) cell count, lymphocyte percentage, CSF protein, CSF glucose/blood glucose, CSF ADA were 54 cells/µL, 98%, 88 mg/dL, 0.622 and 3.5 U/mL respectively. Computed tomography was normal in patients with altered sensorium and cranial nerve deficits. Patients with meningitis had lesser respiratory symptoms and signs and higher urea levels. All patients had received doxycycline except one who additionally received chloramphenicol.

Conclusion

Meningitis in scrub typhus is mild with quick and complete recovery. Clinical features and CSF findings can mimic tuberculous meningitis, except for ADA levels. In the Indian context where both scrub typhus and tuberculosis are endemic, ADA and scrub IgM may be helpful in identifying patients with scrub meningitis and in avoiding prolonged empirical antituberculous therapy in cases of lymphocytic meningitis.

Scrub typhus associated with transient parkinsonism and myoclonus

Parkinsonism with myoclonus is rarely associated with infectious disease in adults. We present a 55-year-old man experiencing acute onset bilateral limb tremor, rigidity, and myoclonus with small-stepped gait, and skin rash involving the trunk and limbs, after a fever. Serum was positive for anti-Orientia tsutsugamushi immunoglobulin M antibody. Brain MRI revealed no abnormalities. The fever improved with oral doxycycline, and the parkinsonism and myoclonus improved with amantadine and clonazepam. This is a rare case of parkinsonism with myolonus associated with scrub typhus infection.