Magnetic resonance imaging in central nervous system tuberculosis

Magnetic resonance imaging findings in central nervous system tuberculosis: A pictorial review

Central nervous system (CNS) tuberculosis is a post-primary form of tuberculosis. It has high mortality and morbidity rates despite early diagnosis and treatment. CNS tuberculosis can manifest as subacute/chronic meningitis, parenchymal tuberculous lesions, and spinal tuberculosis. Hematogenous spread of tuberculous bacilli to the brain results in the development of so called "rich foci" on the pial surface, ependyma, and grey-white matter junction. Rupture of these "rich foci" into the subarachnoid space triggers an intense granulomatous inflammatory reaction. Tuberculous meningitis can manifest as leptomeningitis or pachymeningitis. Intracranial parenchymal tuberculous lesions may present as tuberculoma, tuberculous abscess, cerebritis, rhombencephalitis, and encephalopathy, with atypical presentations not uncommon. Complications of CNS tuberculosis encompass hydrocephalus, syrinx formation, vasculitis, infarcts, neuritis, and enduring neurological deficits. Post-contrast 3D fluid-attenuated inversion recovery (FLAIR) and post-contrast T1 spin-echo sequences excel in detecting tuberculous meningitis compared to other conventional magnetic resonance imaging (MRI) sequences. In proton magnetic resonance spectroscopy (PMRS), the presence of a lipid peak at 1.3 ppm is indicative of tuberculous lesions. Magnetization transfer (MT) imaging enhances the detection of tuberculous lesions, as the magnetization transfer ratio (MTR) of tuberculous pathologies, owing to their high lipid content, is lower than that in bacterial or fungal pathologies and higher than that in viral pathologies. This review article delves into the various typical and atypical imaging presentations of CNS tuberculosis in MRI, along with recent advances in imaging techniques.

A Case of Multiple Brain Tuberculomas in the Subarachnoid Cisterns: Recognition of Radiological Characteristics Regarding the Development of Paradoxical Response during Antituberculosis Treatment

Brain tuberculoma and its occurrence within the subarachnoid cisterns is rare in Japan. Serological and cerebrospinal fluid (CSF) examinations and imaging findings lack specificity; thus, preoperative diagnosis is often challenging. This report presents the case of a 70-year-old woman admitted to our hospital with a one-month history of low-grade fever and altered mental status. Based on the CSF analysis and her history of latent tuberculosis infection seven years ago, she was strongly suspected of suffering from tuberculous meningitis (TBM). Consequently, the patient was enrolled in a clinical trial for antituberculosis treatment (ATT). CSF soluble interleukin-2 receptor level decreased from 2,926 U/mL on day 1 to 225 U/mL 42 days after initiating ATT. Her condition improved after five weeks; however, contrast-enhanced T1-weighted magnetic resonance imaging (MRI) revealed multiple enhanced lesions within the basal subarachnoid cisterns 25 days after admission. As the number and size of these lesions increased, a biopsy confirmed brain tuberculoma diagnosis, and the treatment was continued. In conclusion, when intracisternal scattered mass lesions are identified during TBM treatment, we should consider the possibility of tuberculoma developments arising from a paradoxical response (PR) during the treatment. Serial MRIs are crucial in monitoring PR development in cisternal tuberculomas, an extension of severe TBM. Finally, a PR can be effectively managed by continuing ATT with adjunctive corticosteroids.

Miliary brain tuberculomas and tuberculous meningitis presenting with stroke

Even though it is an uncommon presentation of tuberculosis, tuberculous meningitis is one of the most deadly manifestations. We report a case of a 6-year-old female who presented to the emergency room for left hemiparesis. Cerebral CT and MRI showed a right ischemic stroke with severe leptomeningitis in the medial cranial fossa. Numerous miliary tuberculomas were demonstrated, as well as a moderate hydrocephalus. Lumbar puncture revealed meningitis, and the mycobacterium tuberculosis polymerase chain reaction from CSF was positive. Pulmonary micronodules on chest CT were suggestive of tuberculosis. The clinical and radiological features, as well as the management approaches of this unusual disease complex, are addressed.

Tuberculosis revisted: classic imaging findings in childhood

Tuberculosis (TB) remains one of the major public health threats worldwide, despite improved diagnostic and therapeutic methods. Tuberculosis is one of the main causes of infectious disease in the chest and is associated with substantial morbidity and mortality in paediatric populations, particularly in low- and middle-income countries. Due to the difficulty in obtaining microbiological confirmation of pulmonary TB in children, diagnosis often relies on a combination of clinical and radiological findings. The early diagnosis of central nervous system TB is challenging with presumptive diagnosis heavily reliant on imaging. Brain infection can present as a diffuse exudative basal leptomeningitis or as localised disease (tuberculoma, abscess, cerebritis). Spinal TB may present as radiculomyelitis, spinal tuberculoma or abscess or epidural phlegmon. Musculoskeletal manifestation accounts for 10% of extrapulmonary presentations but is easily overlooked with its insidious clinical course and non-specific imaging findings. Common musculoskeletal manifestations of TB include spondylitis, arthritis and osteomyelitis, while tenosynovitis and bursitis are less common. Abdominal TB presents with a triad of pain, fever and weight loss. Abdominal TB may occur in various forms, as tuberculous lymphadenopathy or peritoneal, gastrointestinal or visceral TB. Chest radiographs should be performed, as approximately 15% to 25% of children with abdominal TB have concomitant pulmonary infection. Urogenital TB is rare in children. This article will review the classic radiological findings in childhood TB in each of the major systems in order of clinical prevalence, namely chest, central nervous system, spine, musculoskeletal, abdomen and genitourinary system.

Role of Multiparametric Magnetic Resonance Imaging of the Brain in Differentiating Neurocysticercosis From Tuberculoma

INTRODUCTION

The two most common infectious causes of ring-enhancing lesions are neurocysticercosis (NCC) and tuberculoma. It is a challenge to differentiate NCC and tuberculomas radiologically since they show the same imaging findings on computed tomography (CT). Hence, this study was performed to assess the role of magnetic resonance imaging (MRI) as an additional advanced modality to aptly characterize the lesion. Conventional MRI with additional advanced imaging sequences like diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC), magnetic resonance spectroscopy (MRS), and post-contrast T1-weighted imaging (T1WI) aids in characterizing the lesion and helps in differentiating NCC and tuberculomas.

OBJECTIVES

To compare the findings of DWI, ADC cut-off values, spectroscopy, and contrast-enhanced MRI in differentiating NCC from tuberculoma.

MATERIALS AND METHODS

Individuals who matched the inclusion criterion underwent an MRI of the brain (plain and contrast) in a 1.5 Tesla, 18-channel, magnetic resonance scanner (Magnetom Avanto®, Siemens Healthineers, Erlangen, Germany). The following imaging sequences were included: T1WI (axial and sagittal), T2-weighted imaging (axial and coronal), fluid-attenuated inversion recovery, DWI at 0, 500, and 1000 mm²/s b-values with corresponding ADC values, and single-voxel MRS. Based on MRI features such as number, size, location, margins of lesions, scolex, surrounding edema, DWI features with corresponding ADC values, enhancement pattern of lesions, and spectroscopy findings, we evaluated and differentiated the lesions as NCC or tuberculoma. Radiological diagnoses were correlated in terms of clinical symptoms and response to treatment.

RESULTS

In our study, 42 subjects were included, of which the total number of NCC cases was 25 (59.52%) and tuberculoma was 17 (40.47%). The mean age of patients included was 42.85 ± 14.76 years (21 to 78 years). On post-contrast imaging, all 25 cases of NCC (100%) showed thin ring enhancement whereas the majority of tuberculomas (64.7%) showed thick irregular ring enhancement. On MRS, all 25 cases (100%) of NCC showed an amino acid peak and all 17 cases (100%) of tuberculoma showed a lipid lactate peak. On DWI, out of 25 NCC cases, restriction of diffusion was absent in the majority of cases (88%) and out of 17 cases of tuberculoma, restriction of diffusion was present in 12 cases (70.5%) (T2 hyperintense tuberculoma, indicative of caseating tuberculoma with central liquefaction) and was absent in the rest. In our study, the mean ADC value of NCC lesions (1.30 ± 0.137 x 10^-3 mm²/s) was found to be greater than that of tuberculoma (0.74 ± 0.090 x 10^-3 mm²/s). ADC value of 1.2 x 10^-3 was obtained as a cut-off to differentiate NCC and tuberculoma. The ADC cut-off value of 1.2 x 10^-3 mm²/s showed a sensitivity of 92% and specificity of 94.1% in differentiating NCC from tuberculoma.

CONCLUSIONS

Conventional MRI with additional advanced imaging sequences like DWI, ADC, MRS, and post-contrast T1WI aids in characterizing the lesion and thereby helps in differentiating NCC and tuberculomas. Hence, multiparametric MRI assessment is useful in making a prompt diagnosis and eliminating the need for a biopsy.

Intracranial giant tuberculoma: A 7-year institutional experience and literature review

BACKGROUND

Intracranial tuberculomas are infrequent with a lower morbidity and mortality compared to tubercular meningitis. Giant intracranial tuberculomas are rarer but important differentials for intracranial space-occupying lesions causing focal neurological deficits depending on anatomical location and size.

METHODS

Histopathologically confirmed giant intracranial tuberculomas selected based on institutional size criteria (<12 Years-old: ≥25 mm; 12-18 Years-old: ≥35 mm; ≥18 Years-old: ≥40 mm) were retrospectively reviewed and analyzed for clinical features, radiology, surgical management, and outcomes in patients admitted from 2015 to 2022.

RESULTS

Ten patients were included (Males:Females = 3:7; Age: 8-68 Years, Average: 30.1 Years). Mean duration of symptoms was 2.84 months. Two patients demonstrated active systemic tuberculosis. Previous tubercular infections included pulmonary involvement in four, meningeal in three, and a cerebellar tuberculoma in one patient. Cerebrospinal fluid analysis in five patients demonstrated no tubercle bacilli. Seven lesions were supratentorial and three infratentorial. Giant tuberculomas demonstrated profound T2 hypointensity, sub-marginal T2 hyperintense crescents, and significant perilesional vasogenic edema. Craniotomy and excision were mainstay except in one case treated only with ventriculoperitoneal shunting. Three additional patients underwent ventriculoperitoneal shunting for hydrocephalus. One patient died from aspiration pneumonia and sepsis following a postoperative seizure. Anti-Tubercular Therapy (ATT) was advised for 18 months. Follow up ranged from 4 to 18 months. One patient was medically managed for ATT-induced hepatitis, hepatic encephalopathy, and coincidental paradoxical reaction. Remainder of patients showed complete resolution of symptomatology and absence of new symptoms till latest follow up.

CONCLUSION

Clinical course of giant tuberculomas differ from non-giant variants in characteristic radiology, more intensive ATT, and possibility for partial debulking/excision.

Magnetic Resonance Imaging Appearance of Giant Intracerebral Tuberculoma: A Retrospective Analysis

Background: Giant intracerebral tuberculomas are rare lesions but should be considered in the differential diagnosis of intracranial space-occupying lesion in an endemic region.Objective: The purpose of this study is to analyze the clinical data and magnetic resonance imaging (MRI) findings of giant intracerebral tuberculomas to improve the diagnostic precision.Material and Methods: The clinical and MRI findings of 22 patients of giant intracerebral tuberculoma were analyzed retrospectively. For the statistical analysis independent sample Student t-test was used.Results: For 22 patients included in this sample the giant intracerebral tuberculoma was of size more than 2.5cm. The majority of the giant tuberculomas (19 patients (86.4%))was located in the supratentorial area.T2-weighted hypointense core of giant tuberculoma was observed in 12 patients (54.5%) and T1 hyperintensities were observed in peripheral (wall) of the giant tuberculoma in 14 patients (63.6%). The mean ADC value of the peripheral (wall) of the giant tuberculoma was 1.034± 0.466[SD] x 10-3mm2/s and the core was 0.994± 0.455[SD] x 10-3mm2/s with a statistically significant difference (p-value <0.0005) in between. MR spectroscopy showed raised lipid peak at 0.9 to 1.33 ppm in 10 patients (45.5%),raised lipid-lactate peak in 12 patients (54.5%),raised Choline/Cr ratio more than 1.2 in 14 patients(63.6%) and Choline/Cr ratio less than 1.2 in 5 patients (22.7%). Associated involvement of lung was observed in the 6patients (27.3%), cervical lymph node in 1 patient (4.5%) and spine in 1patient (4.5%).Conclusions: MRI plays a vital role in distinguishing giant intracerebral tuberculomas from other intracranial space-occupying lesions, thereby allows the early institution of anti-tubercular treatment (ATT), decreased patient morbidity, mortality, and prevents unnecessary neurosurgical excision.

Role of Caspase- 3, TNF-α, and IL6 mRNA Expression in Intracranial Tuberculoma

The development of tuberculoma is a process of inflammation, necrosis, and apoptosis. Therefore, the pro-inflammatory cytokines and apoptosis biomarkers are likely to play an important role. In this study, we report the expression of TNFα, IL6, and caspase-3 at the mRNA level in the patients with tuberculous meningitis (TBM) and compare these biomarkers in the patients with and without tuberculoma. A total of 134 patients with TBM and 35 matched healthy controls were included. The clinical, cerebrospinal fluid (CSF), and cranial magnetic resonance imaging (MRI) findings were noted. The mRNA expression of TNFα, IL6, and caspase-3 in peripheral blood mononuclear cells was evaluated by reverse transcriptase polymerase chain reaction. On cranial MRI, 89 (64.2%) patients had tuberculoma, and their level of consciousness, severity of meningitis, CSF findings, and blood counts were not significantly different from those without tuberculoma. Patients with tuberculoma had a higher expression of TNFα and IL6 compared to the controls, but had lower expression compared to the patients without tuberculoma. TNFα expression positively correlated with the expression of caspase-3, but not with IL6. Twenty-five (18.6%) patients died: 12 (13.5%) in tuberculoma and 13 (28.9%) in the non-tuberculoma group. Death was related to higher expression of TNFα and caspase-3. The lower expression of TNFα and IL6 in intracranial tuberculoma suggests that these patients are unlikely to be benefited with TNFα blockers.

Lessons learned from a fatal case of tuberculous meningitis with a rapid decline in an infant

Tuberculous meningitis is a highly lethal, often underrecognized disease with characteristic clinical and imaging features which can be cured if the diagnosis and subsequent treatment are begun at early stages. Frequently, there is a delayed diagnosis of this condition due to unfamiliarity of clinicians in non-endemic areas about its presentation and diagnostic workup. This article presents a case of rapid decline and fatality due to tuberculous meningitis in an 11-month-old child from a non-TB-endemic area and describes the characteristic clinical presentation, imaging findings, and diagnostic pitfalls associated with this condition.

Tuberculoma - a great mimicker: can diffusion tensor imaging and tractography help?

BACKGROUND

Central nervous system (CNS) tuberculomas often mimic tumors on conventional imaging, differentiation of which may not be possible without invasive tissue sampling. Diffusion tensor imaging (DTI), owing to its unrivalled property of characterizing molecular diffusion, may help in better lesion characterization and tractography may help understand the pattern of white matter involvement by tuberculomas.

PURPOSE

To estimate qualitative and quantitative diffusion tensor changes in brain tuberculomas and to evaluate patterns of white matter involvement using 3D tractography.

MATERIAL AND METHODS

Thirty patients with brain tuberculomas were evaluated on a 3-T magnetic resonance scanner. Diffusion tensor images were acquired along 20 non-colinear encoding directions with two b-values (b = 0, b = 1000). Regions of interest (ROIs) were drawn on quantitative fractional anisotropy (FA) and apparent diffusion coefficient (ADC) maps in the center of the tuberculoma and perilesional area. Similar ROIs were placed in contralateral hemispheres for comparison. Tractography maps were also generated.

RESULTS

Mean FA in the center and perilesional area of tuberculomas were 0.098 ± 0.041 and 0.311 ± 0.135, respectively. ADC values in corresponding regions were 0.920 ± 0.272 ×10^-3 mm²/s and 1.157 ± 0.277 ×10^-3 mm²/s. These values were significantly different compared to contralateral similar brain parenchyma. Tractography revealed interruption of white fibers in the center with deviation of fibers at the periphery in the majority of tuberculomas with none showing infiltration of white matter described in tumors.

CONCLUSION

Significant qualitative as well as quantitative DTI changes were seen in tuberculoma and perilesional areas compared to contralateral hemisphere with tractography showing a pattern different from that described in tumors. These findings may help to differentiate tuberculomas from infiltrating tumors.

Intraventricular tuberculosis abscess in an immunocompromised patient: clinical vignette

Tuberculosis is caused by Mycobacterium tuberculosis. Tuberculosis of the central nervous system is common and manifestations include meningeal and intraparenchymal diseases. However, intraventricular tuberculous abscess is a rare manifestation of intracranial tuberculous infection. We present a case of an immunocompromised female patient with high-grade fever and signs of meningism. The computed tomography and magnetic resonance imaging (MRI) of the brain showed hydrocephalus with rim-enhancing lesion in the right lateral ventricle. The MRI demonstrated a hypointense signal on T1-weighted imaging, hyperintense signal on T2-weighted imaging, and mild restricted diffusion in diffusion-weighted imaging. She underwent emergency external ventricular drainage and frank pus was drained. Diagnosis of tuberculosis was made via polymerase chain reaction analysis and culture. Understanding the intracranial manifestation of neurotuberculosis is imperative to arrive at the diagnosis correctly and ensure prompt treatment.

Giant tuberculoma of the corpus callosum, the unforeseen diagnosis

OBJECTIVE

Isolated intracranial tuberculomas are rare, especially in adults and it is not uncommon that they are easily confused with other diseases. To address this issue, we reported a case of a tuberculoma of the corpus callosum focusing on clinical characteristics, diagnostic clues, and outcome.

CONCLUSIONS

Intracranial masses are frequently targeted as neoplastic pathology with surgical treatment in most cases. It is important to distinguish between neuro tuberculoma and brain tumors because of their different management and prognosis. Therefore even in absence of a known history of primary TB and in immunocompetent patients, tuberculoma must be in the differential diagnosis of solitary intracranial lesions also in countries where TB is not endemic.

Intracranial Tuberculoma Mimicking Neurosarcoidosis: A Clinical Challenge

Central nervous system (CNS) tuberculosis is a rare manifestation of all tuberculosis presentations. The incidence of brain tuberculoma is increasing in developed countries due to HIV infection and immigration from tuberculosis-endemic countries. Symptoms and radiologic findings of CNS tuberculosis can be non-specific and lead to misdiagnosis or mistreatment. Intracranial tuberculoma can present with a seizure, intracranial hypertension, or focal neurologic symptoms. In our case, the diagnosis was challenging between neurosarcoidosis and intracranial tuberculoma due to inconclusive results of stereotactic brain biopsy and clinical presentation. The pathology result of the open brain biopsy revealed non-caseating granuloma. Finally, we were able to diagnose intracranial tuberculoma following acid-fast bacilli culture results of open brain biopsy. This report highlights the importance of including intracranial tuberculoma in the differential diagnosis of cerebral space-occupying lesions, even in patients with negative laboratory findings of tuberculosis.

MRI findings in tubercular radiculomyelitis

This article aims to familiarize the reader with the MR imaging findings of tubercular radiculomyelitis (TBRM) and to identify the sources of infection. We evaluated 29 patients on a 1.5 T GE MRI in a cross-sectional study. MRI of the spine with contrast and lumbar puncture were performed in all patients. MRI brain was performed for 13 patients. The typical and atypical manifestations enlisted in this article, will enable early detection of TBRM when the clinical history is ambiguous, as TBRM can present with low backache in both retrovirus positive and negative patients.

Clinical Application of Magnetic Resonance Spectroscopy in Diagnosis of Intracranial Mass Lesions

Introduction

Conventional MR imaging provides highly detailed anatomic information with unrivalled soft tissue contrast making it the mainstay in the diagnosis of suspected brain lesions. Despite this, MRI alone at times cannot answer the diagnostic questions in quite a few patients. Proton MR Spectroscopy (H-MRS) provides information on the metabolic composition within an area under interrogation. By comparing the relative concentrations of specific metabolites, the neuroradiologist can deduce critical information regarding neuronal cell density and integrity, cell membrane turnover, metabolic fuel, and possible necrosis in the region of interest. This provides a biochemical picture of the underlying pathology and thus aids in the diagnosis.

Methods

This was a cross-sectional comparative study.

Results

Of the 63 patients examined by MRI and MRS for intracranial mass lesions, the radiologists were able to offer a single imaging diagnosis based on MRI alone in only 15 patients (23.8%) while when MRI imaging was combined with MR spectroscopy, a single imaging diagnosis was offered in 47 patients (74.6%). This was an overall statistically significant improvement.

Conclusion

MRS aided the radiologist in offering a single diagnosis in high versus low-grade gliomas, high-grade gliomas versus tuberculomas, and recurrent tumours versus radiation necrosis.

Giant Tuberculomas of Brain: Rare Neoplastic Mimic

Objective

Tuberculosis continues to be a major infectious disease in developing parts of the world. Primarily central nervous system tuberculosis manifests as meningitis, tuberculoma, or a brain abscess; however, rarely it may manifest as a large neoplastic mass such as lesion known as giant tuberculoma. Especially in central parts of India, the incidence of giant tuberculoma is quite high in pediatric population that too in posterior fossa of brain. Often, they are wrongly reported as neoplastic masses on imaging. The objective of this study was to evaluate different imaging appearances of a giant tuberculoma.

Materials and Methods

In this prospective study, all cases of giant tuberculoma presenting to a large tertiary care center in central India for 2 years (duration 2016-2018) were imaged and followed up. A total of nine patients, six females and three males, aged 4-16 years were studied on a 3-Tesla Siemens magnetic resonance imaging (MRI) scanner.

Results

In total, nine patients were included with 11 giant tuberculomas. Of 11, eight were infratentorial and three were supratentorial in location. On T2-weighted image sequence, these lesions showed central hypointensity with a peripheral hyperintense rim. Most observed finding on T1-weighted image sequence was central isointensity with peripheral hyperintense rim. Advanced imaging sequences such as magnetic resonance spectroscopy and magnetization transfer were also applied.

Conclusion

To the best of our knowledge, this is the largest series of giant tuberculoma in the pediatric population reported so far in any part of the world. We have described the various MRI imaging findings of this lesion in great details. Management of such rare cases and pertinent literature is reviewed briefly.

Intramedullary Conus Medullaris Tuberculoma: A Case Report and Review of the Literature

Intramedullary tuberculoma (IMT) of the conus medullaris is extremely rare. We present a case of intramedullary conus medullaris tuberculoma in which the diagnosis was based on there being very high levels of adenosine deaminase (ADA) in the patient’s cerebrospinal fluid (CSF) and improvement with antituberculous therapy. A 78-year-old man presented after having had a dull ache in both thighs and progressive paraparesis. The patient’s medical history included diffuse large B-cell lymphoma, which had undergone remission due to chemotherapy two years earlier, and long-term, well-controlled diabetes. A chest X-ray showed no evidence of tuberculosis. The results of CSF analysis were compatible with Froin’s syndrome. An initial diagnosis was made of an intramedullary tumor of the conus medullaris, based on magnetic resonance imaging (MRI). A myelotomy and multiple punch out biopsy were performed, and histopathology of the tissues revealed mild reactive gliosis. Due to the patient having high levels of CSF-ADA, IMT of the conus medullaris was suspected. The patient was treated with an 18-month course of antituberculous therapy. The dull ache gradually disappeared, and motor power improved slightly. A follow-up MRI of the lumbosacral (LS) spine revealed that the lesion had completely disappeared. Intramedullary tuberculoma of the conus medullaris should be considered in patients with underlying malignancy and no symptoms of systemic tuberculosis. CSF adenosine deaminase levels can be helpful in determining the presence of central nervous system tuberculosis when other systemic signs of disease are lacking.

MRI in intracranial tuberculosis: Have we seen it all?

Tuberculosis is emerging worldwide across diverse populations and geographies; unrestricted by the social divide and the geographical barriers in today's interconnected world. This rise in its prevalence can be linked to multiple factors including urbanisation, spurt in global travel, population explosion, migration and HIV infection. The varied and complex clinical presentation of intracranial tuberculosis tricks even the best of the clinicians. This along with the other facets associated with its management including drug resistance, paradoxical reaction, underlying HIV infection can make it particularly challenging. Imaging has a definitive role in the evaluation and follow-up of intracranial tuberculosis and MRI is the cornerstone in this regard. Typical features of intracranial tuberculosis are well-described. However, it is not infrequent to encounter atypical and bizarre presentations, both clinically and on imaging. A holistic clinical and imaging review of difficult cases, including newer MRI techniques, is necessary for the neuroradiologist, neurologist and the neurosurgeon to arrive at the right diagnosis in a timely fashion.

Optic Neuritis

PURPOSE OF REVIEW

This article discusses the clinical presentation, evaluation, and management of the patient with optic neuritis. Initial emphasis is placed on clinical history, examination, diagnostic testing, and medical decision making, while subsequent focus is placed on examining specific inflammatory optic neuropathies. Clinical clues, examination findings, neuroimaging, and laboratory testing that differentiate autoimmune, granulomatous, demyelinating, infectious, and paraneoplastic causes of optic neuritis are assessed, and current treatments are evaluated.

RECENT FINDINGS

Advances in technology and immunology have enhanced our understanding of the pathologies driving inflammatory optic nerve injury. Clinicians are now able to interrogate optic nerve structure and function during inflammatory injury, rapidly identify disease-relevant autoimmune targets, and deliver timely therapeutics to improve visual outcomes.

SUMMARY

Optic neuritis is a common clinical manifestation of central nervous system inflammation. Depending on the etiology, visual prognosis and the risk for recurrent injury may vary. Rapid and accurate diagnosis of optic neuritis may be critical for limiting vision loss, future neurologic disability, and organ damage. This article will aid neurologists in formulating a systematic approach to patients with optic neuritis.

Central Nervous System involvement in tuberculosis: An MRI study considering differences between patients with and without Human Immunodeficiency Virus 1 infection

BACKGROUND

Magnetic resonance imaging (MRI) is largely used in the diagnosis of central nervous system involvement of tuberculosis (CNSTB), yet there is no MRI comparison study between HIV+ and HIV- patients with CNSTB. The aim of the present study was to identify MRI differences in CNSTB between HIV+ and HIV- patients and possibly find early characteristics that could raise the suspect of this disease.

METHODS

We included all patients admitted in our institution between 2011 and 2018 with confirmed diagnosis of CNSTB, and MRI performed in the first week. Patients with preexisting brain pathology or immunodeficiency not HIV related were excluded. We compared CNSTB MRI features between the two groups.

RESULTS

Sixty-nine patients were included (19 HIV+; 50 HIV-). Findings in HIV+ group: 6 lung TB, 5 hydrocephalus, 4 meningeal enhancement, 6 stroke, 2 hemorrhages, and 10 tuberculomas. HIV- group: 22 lung tuberculosis, 15 hydrocephalus, 21 meningeal enhancement, 5 stroke, 4 hemorrhages, 20 tuberculomas. The only statistically significant difference between the two groups was in the stroke occurrence, more frequent in the HIV+ group (P=.028), all involving the basal ganglia.

CONCLUSIONS

Stroke involving the basal ganglia best differentiates CNSTB patients who are HIV+ from those HIV-. This finding was not correlated with meningeal enhancement suggesting that small arteries involvement might precede it. Therefore, we think that HIV+ patients with a new onset of stroke should be evaluated for CNSTB. Follow-up MRI should also be planned since meningeal enhancement might appear in later stages of the disease.

Diagnosis and Management of Multidrug-Resistant Tuberculosis in Children: A Practical Approach

Approximately 25,000 children develop multidrug-resistant (MDR) tuberculosis (TB) each year, but few of them are diagnosed and appropriately treated for MDR-TB. New diagnostic tools have improved our ability to diagnose children with bacteriologically confirmed TB earlier. However, the majority of childhood TB cases are not bacteriologically confirmed; therefore a high index of suspicion is needed, and taking a detailed history of contact with drug-resistant source cases and previous TB treatment is important to identify presumed MDR-TB cases. Treatment for MDR-TB is rapidly changing with the addition of new and repurposed drugs, the introduction of shorter regimens and the move towards injectable-free, all-oral MDR-TB treatment regimens. Children have been neglected in the introduction of the new drugs, but drug dosing and safety studies are now being completed. This article presents a practical approach in deciding which regimen to use in individual children in need of MDR-TB treatment. Outcomes in those treated are generally good, but only <5% of children with MDR-TB are currently diagnosed and appropriately treated. Diagnosing children with MDR-TB and getting them on to correct treatment regimens should now be our main focus.

Tuberculosis of the Central Nervous System

PURPOSE OF REVIEW

This article details the epidemiology and clinical manifestations of central nervous system (CNS) tuberculosis (TB), provides guidance for diagnostic imaging and CSF testing, and recommends treatment strategies for tuberculous meningitis and other forms of CNS TB, illustrating key aspects of diagnosis and management with case presentations.

RECENT FINDINGS

Although improvements in our understanding of the pathogenesis and management of CNS TB have occurred over the past 50 years, the emergence of multidrug-resistant and extensively drug-resistant TB, the advent of acquired immunodeficiency syndrome (AIDS), and the subsequent availability of highly active antiretroviral therapy that can produce the immune reconstitution inflammatory syndrome have complicated the diagnosis and treatment of CNS TB. Advances in diagnostic assays promise to increase the speed of diagnosis as well as the percentage of people with a confirmed rather than a presumptive diagnosis. Advances in precision medicine have identified polymorphisms in the LTA4H gene that influence the risk for inflammation in patients with tuberculous meningitis.

SUMMARY

CNS TB continues to be a major cause of morbidity and mortality, with the majority of people affected living in low-income and middle-income countries. Newer diagnostic assays promise to increase the speed of diagnosis and improve appropriate selection of antituberculous therapy and anti-inflammatory medications. Despite these advances, CNS TB remains difficult to diagnose, and clinicians should have a low threshold for initiating empiric therapy in patients with presumptive infection.

A rare neurological complication of tuberculosis: Transverse myelitis

Acute transverse myelitis is a rare inflammatory demyelinating disorder characterized by relatively acute onset of motor, sensory, and autonomic dysfunction. Mycobacterium tuberculosis is a very rare cause of transverse myelitis. We present a patient with tuberculosis presenting with meningitis and transverse myelitis who had marked clinical improvement and neurologic recovery after treatment of tuberculosis and intravenous steroid pulses.

Magnetic resonance imaging spectrum of intracranial tubercular lesions: one disease, many faces

Tuberculosis is a devastating disease and has shown resurgence in recent years with the advent of acquired immunodeficiency syndrome. Central nervous system involvement is the most devastating form of the disease, comprising 10% of all tuberculosis cases. The causative organism, Mycobacterium tuberculosis, incites a granulomatous inflammatory response in the brain, the effects of which can be appreciated on magnetic resonance imaging (MRI), which can thus be used for diagnosis of the same. Neurotuberculosis can present in various patterns, which can be identified on MRI. The meningeal forms include leptomeningitis and pachymeningitis. Parenchymal forms of neurotuberculosis include tuberculoma in its various stages, tubercular cerebritis and abscess, tubercular rhombencephalitis, and tubercular encephalopathy. Each pattern has characteristic MRI appearances and differential diagnoses on imaging. Complications of neurotuberculosis, usually of tubercular meningitis, include hydrocephalus, vasculitis, and infarcts as well as cranial nerve palsies. Various MRI sequences besides the conventional ones can provide additional insight into the disease, help in quantifying the disease load, and help in differentiation of neurotuberculosis from conditions with similar imaging appearances and presentations. These can enable accurate and timely diagnosis by the radiologist and early institution of treatment in order to reduce the likelihood of permanent neurological sequelae.

Progress on Diagnosis of Tuberculous Meningitis

Central nervous system (CNS) disease caused by Mycobacterium tuberculosis (MTB) is highly devastating. Tuberculous meningitis (TBM) is the most common form of CNS tuberculosis (TB). Rapid, sensitive, and affordable diagnostic tests are not available. Ziehl-Neelsen (ZN) stain has a very low sensitivity in cases of TBM, the sensitivity rates is of about 10-20%.The detection rate can be improved by taking large volume CSF samples (>6 ml) and prolonged slide examination (30 min). Culture of MTB from the CSF is slow and insufficiently sensitive. The sensitivity is different, which varies from 36% to 81.8%. The microscopic observation drug susceptibility (MODS) assay was recommended by the World Health Organization in 2011. The sensitivity is 65%, which is more sensitive and faster than CSF smear. Commercial PCR assays were found to be insensitive at detecting MTB in CSF samples. Many research provided the value of ADA on the TBM diagnosis. Interferon-gamma release assays (IGRAs) are not recommended for diagnosis of active TB disease. Imaging is essential in diagnosis and showing complications of CNS TB. Thwaites criteria and the Lancet consensus scoring system (LCSS) were developed to improve the diagnosis of TBM. Clinicians will continue to make judgment based on clinical examination, inflammatory CSF examinations, imaging studies, and scoring systems.

Tuberculosis Test Usage and Medical Expenditures from Outpatient Insurance Claims Data, 2013

Objective

To evaluate TB test usage and associated direct medical expenditures from 2013 private insurance claims data in the United States (US).

Methods

We extracted outpatient claims for TB-specific and nonspecific tests from the 2013 MarketScan® commercial database. We estimated average expenditures (adjusted for claim and patient characteristics) using semilog regression analyses and compared them to the Centers for Medicare and Medicaid Services (CMS) national reimbursement limits.

Results

Among the TB-specific tests, 1.4% of the enrollees had at least one claim, of which the tuberculin skin test was most common (86%) and least expensive ($9). The T-SPOT® was the most expensive among the TB-specific tests ($106). Among nonspecific TB tests, the chest radiograph was the most used test (78%), while chest computerized tomography was the most expensive ($251). Adjusted average expenditures for the majority of tests (≈74%) were above CMS limits. We estimated that total United States medical expenditures for the employer-based privately insured population for TB-specific tests were $53.0 million in 2013, of which enrollees paid 17% ($9 million).

Conclusions

We found substantial differences in TB test usage and expenditures. Additionally, employer-based private insurers and enrollees paid more than CMS limits for most TB tests.

Vision loss in tuberculous meningitis

Vision loss is a disabling complication of tuberculous meningitis. Approximately, 15% of survivors are either completely or partially blind. All structures of the visual pathway may be affected in tuberculous meningitis. Optic nerve and optic chiasma are most frequently and dominantly affected. Thick-gelatinous exudates lying over the base of brain, are the pathological hallmark of tuberculous meningitis and are responsible for almost all of its major complications, including vision loss. Strangulation of optic nerves and optic chiasma by the exudates, compression over optic chiasma by the dilated third ventricle, raised intracranial pressure, endarteritis, shunt failure, bacterial invasion of optic nerves and drug-induced optic nerve damage are important reasons that are considered responsible for vision loss. Prompt antituberculosis treatment is the best management option available. Immunomodulatory drugs and cerebrospinal fluid diversion procedures are of limited help. Early recognition and treatment of tuberculous meningitis is the only way forward to tackle this problem.

Imaging in tuberculosis

Early diagnosis of tuberculosis (TB) is necessary for effective treatment. In primary pulmonary TB, chest radiography remains the mainstay for the diagnosis of parenchymal disease, while computed tomography (CT) is more sensitive in detecting lymphadenopathy. In post-primary pulmonary TB, CT is the method of choice to reveal early bronchogenic spread. Concerning characterization of the infection as active or not, CT is more sensitive than radiography, and (18)F-fluorodeoxyglucose positron emission tomography/CT ((18)F-FDG PET/CT) has yielded promising results that need further confirmation. The diagnosis of extrapulmonary TB sometimes remains difficult. Magnetic resonance imaging (MRI) is the preferred modality in the diagnosis and assessment of tuberculous spondylitis, while (18)F-FDG PET shows superior image resolution compared with single-photon-emitting tracers. MRI is considered superior to CT for the detection and assessment of central nervous system TB. Concerning abdominal TB, lymph nodes are best evaluated on CT, and there is no evidence that MRI offers added advantages in diagnosing hepatobiliary disease. As metabolic changes precede morphological ones, the application of (18)F-FDG PET/CT will likely play a major role in the assessment of the response to anti-TB treatment.

Spinal Nerve Root Enhancement on MRI Scans in Children: A Review

Spinal nerve root enhancement in pediatric patients is generally nonspecific, and clinical and laboratory correlation is essential. Nerve root enhancement indicates lack of integrity of the blood-nerve barrier. In this review, we will present a range of pediatric conditions that can present with spinal nerve root enhancement including inflammatory, infectious, hereditary, and neoplastic causes. Familiarity with the various pathologic entities associated with spinal nerve root enhancement is important for a concise differential diagnosis in the appropriate clinical setting. This will avoid unnecessary additional investigations.

Magnetic resonance imaging of infectious meningitis and ventriculitis in adults

Magnetic resonance imaging findings of meningitis are usually nonspecific with respect to the causative pathogen because the brain response to these insults is similar in most cases. In this article, we will use a few representative cases to describe the characteristic magnetic resonance findings of meningitis and its complications, including ventriculitis.

Imaging of the brain in patients with human immunodeficiency virus infection

Neurologic disease in acquired immunodeficiency syndrome (AIDS) patients is related either to opportunistic pathogens or to direct central nervous system (CNS) invasion by the human immunodeficiency virus. Despite the increasing availability of antiretroviral therapy, opportunistic infections continue to afflict patients in the developing world and in other populations with limited access to appropriate treatment. Classic CNS infections in the setting of AIDS include toxoplasmosis, cryptococcosis, progressive multifocal leukoencephalopathy, and cytomegalovirus encephalitis. Additionally, AIDS patients are far more susceptible to acquiring CNS tuberculosis and neurosyphilis, both of which exhibit altered disease characteristics in the setting of immunosuppression. Neuroimaging is a crucial component of the diagnostic work-up of these conditions, and findings include, but are not limited to, intracranial mass lesions, white matter disease, meningoencephalitis, vascular complications, and hydrocephalus. Though various disease processes can produce imaging findings that overlap with one another, certain characteristic patterns may suggest a particular pathogen, and advanced imaging techniques and laboratory tests allow for definitive diagnosis. Knowledge of the imaging patterns seen in the setting of AIDS-related CNS disease is vital to the neuroradiologist, whose interpretation may guide decisions related to treatment and further work-up.

Radiological Follow-up of a Cerebral Tuberculoma with a Paradoxical Response Mimicking a Brain Tumor

We report a case of a paradoxical response of a tuberculoma in the brain mimicking a brain tumor. A 76-year-old woman presented with a 2 week history of headache, dysarthia, and orthopnea. Brain magnetic resonance images (MRI) revealed two rim-enhancing lesions on the pons and occipital lobe, and chest computed tomography showed randomly distributed miliary nodules. The tentative diagnosis was tuberculosis (TB) of the brain and lung. She complained of right hemiparesis and worsening general weakness after taking the anti-TB medication. On the monthly follow-up images, the enhanced lesions were enlarged with increased perfusion and choline/creatinine ratio, suggesting a high grade glioma. A surgical resection was completed to diagnose the occipital lesion, and the tuberculoma was pathologically confirmed by a positive TB-polymerase chain reaction. The anti-TB medication was continued for 13 months. A follow-up MRI showed decreased size of the brain lesions associated with perilesional edema, and the clinical symptoms had improved. Brain tuberculoma could be aggravated mimicking brain malignancy during administration of anti-TB medication. This paradoxical response can be effectively managed by continuing the anti-TB drugs.

Imaging in tuberculosis

Despite many advances in both diagnosis and treatment, tuberculosis still remains one of commonest causes of morbidity and mortality from any infectious cause in the world. Although the overall incidence and mortality rate for tuberculosis has decreased over the years, timely and accurate diagnosis of tuberculosis is essential for the health of the patient as well as the public. For the diagnosis of tuberculosis, a high degree of clinical suspicion is required, and this becomes much more important in high-risk populations. Tuberculosis may masquerade as any disease; therefore, tissue and microbiological assessment is sometimes important for establishing the diagnosis. However, in daily practice, the clinician and radiologist should be familiar with the imaging features of pulmonary and extrapulmonary tuberculosis, as well as manifestations of tuberculosis in immunocompromised patients. Imaging provides a very important role in the diagnosis and management of tuberculosis. Although chest X rays remain the basic imaging modality for pulmonary tuberculosis, computed tomography, magnetic resonance imaging, and nuclear medicine techniques, including positron emission tomography/computed tomography, are extremely helpful in the assessment of both pulmonary and extrapulmonary tuberculosis.

Central nervous system tuberculosis: an imaging-focused review of a reemerging disease

Central nervous system (CNS) tuberculosis is a potentially life threatening condition which is curable if the correct diagnosis is made in the early stages. Its clinical and radiologic manifestations may mimic other infectious and noninfectious neurological conditions. Hence, familiarity with the imaging presentations of various forms of CNS tuberculosis is essential in timely diagnosis, and thereby reducing the morbidity and mortality of this disease. In this review, we describe the imaging characteristics of the different forms of CNS tuberculosis, including meningitis, tuberculoma, miliary tuberculosis, abscess, cerebritis, and encephalopathy.

Posterior fossa tuberculoma in a Huichol native Mexican child: a case report

BACKGROUND

Tuberculosis is a major health concern in Mexico, especially among the native population. Tuberculomas are a frequent and severe complication of pediatric tuberculosis, these are observed as tumors in neuroimaging studies but are often not diagnosed adequately.

CASE PRESENTATION

We present a case of a 12-year-old native Mexican girl Huichol ethnicity diagnosed with a large posterior fossa tuberculoma found by imaging. This tuberculoma was surgically removed. Histopathologic examination and staining with hematoxylin and eosin, and Ziehl-Neelsen techniques of the surgical specimen were performed. Cerebrospinal fluid was analyzed by using the newly available Xpert® MTB/RIF assay (Cepheid, Sunnyvale CA, USA). Granulomatous inflammation with central caseous necrosis surrounded by edematous brain with reactive gliosis and acid-fast bacilli were revealed on histopathologic analysis. Mycobacterium tuberculosis DNA susceptible to rifampicin was detected in the patient's cerebrospinal fluid and the patient was started on anti-tuberculosis treatment. The girl continued to show severe neurologic damage despite surgery and anti-tuberculosis treatment, and she eventually died of respiratory complications.

CONCLUSION

Our case highlights the need for early confirmation of tuberculoma diagnosis by molecular assay so that timely treatment can be initiated to prevent severe brain damage. Furthermore, it emphasizes the need to consider tuberculomas in the differential diagnosis of children with neurologic symptoms living in areas of high tuberculosis incidence and those belonging to native populations in developing countries.

MRI in central nervous system infections: A simplified patterned approach

Recognition and characterization of central nervous system infections poses a formidable challenge to the neuro-radiologist. Imaging plays a vital role, the lesions typically being relatively inaccessible to tisue sampling. The results of an accurate diagnosis are endlessly rewarding, given the availability of excellent pharmacological regimen. The availability of numerous magnetic resonance (MR) sequences which provide functional and molecular information is a powerful tool in the hands of the radiologist. However, the plethora of sequences and the possibilities on each sequence is also intimidating, and often confusing as well as time consuming. While a large number of reviews have already described in detail the possible imaging findings in each infection, we intend to classify infections based on their imaging characteristics. In this review we describe an algorithm for first classifying the imaging findings into patterns based on basic MR sequences (T1, T2 and enhancement pattern with Gadolinium), and then sub-classify them based on more advanced molecular and functional sequences (Diffusion, Perfusion, Susceptibility imaging, MR Spectroscopy). This patterned approach is intended as a guide to radiologists in-training and in-practice for quickly narrowing their list of differentials when faced with a clinical challenge. The entire content of the article has also been summarised in the form of flow-charts for the purpose of quick reference.

Diffusion tensor imaging study of white matter damage in chronic meningitis

Tuberculous meningitis (TBM) and cryptococcal meningitis (CM) are two of the most common types of chronic meningitis. This study aimed to assess whether chronic neuro-psychological sequelae are associated with micro-structure white matter (WM) damage in HIV-negative chronic meningitis. Nineteen HIV-negative TBM patients, 13 HIV-negative CM patients, and 32 sex- and age-matched healthy volunteers were evaluated and compared. The clinical relevance of WM integrity was studied using voxel-based diffusion tensor imaging (DTI) magnetic resonance imaging. All of the participants underwent complete medical and neurologic examinations, and neuro-psychological testing. Differences in DTI indices correlated with the presence of neuro-psychological rating scores and cerebrospinal fluid (CSF) analysis during the initial hospitalization. Patients with CM had more severe cognitive deficits than healthy subjects, especially in TBM. There were changes in WM integrity in several limbic regions, including the para-hippocampal gyrus and cingulate gyrus, and in the WM close to the globus pallidus. A decline in WM integrity close to the globus pallidus and anterior cingulate gyrus was associated with worse CSF analysis profiles. Poorer DTI parameters directly correlated with worse cognitive performance on follow-up. These correlations suggest that WM alterations may be involved in the psychopathology and pathophysiology of co-morbidities. Abnormalities in the limbic system and globus pallidus, with their close relationship to the CSF space, may be specific biomarkers for disease evaluation.