Subarachnoid neurocysticercosis: emerging concepts and treatment

Current challenges in neurocysticercosis: recent data and where are we heading

PURPOSE OF REVIEW

Neurocysticercosis (NCC) is still a significant contributor to neurological disease in vast regions of the world, and increasingly diagnosed in nonendemic countries because of travel and immigration from endemic settings. There is a need for clinicians in endemic and nonendemic regions to understand the complexities of its diagnosis and management.

RECENT FINDINGS

Recent information on the performance and use of available imaging and immunodiagnostic tools as well as antiparasitic and anti-inflammatory therapeutic regimes were assessed.

SUMMARY

Imaging and serology data should be assessed in the context of the specific type of NCC to improve diagnostic precision. In terms of therapeutic approaches, more controlled data is required on the efficacy and safety of combined antiparasitic therapy, and antiseizure and anti-inflammatory regimes should be optimized to minimize perilesional damage and reduce the risk of epilepsy.

Transcriptomic analysis of subarachnoid cysts of Taenia solium reveals mechanisms for uncontrolled proliferation and adaptations to the microenvironment

Subarachnoid neurocysticercosis (SANCC) is caused by an abnormally transformed form of the metacestode or larval form of the tapeworm Taenia solium. In contrast to vesicular parenchymal and ventricular located cysts that contain a viable scolex and are anlage of the adult tapeworm, the subarachnoid cyst proliferates to form aberrant membranous cystic masses within the subarachnoid spaces that cause mass effects and acute and chronic arachnoiditis. How subarachnoid cyst proliferates and interacts with the human host is poorly understood, but parasite stem cells (germinative cells) likely participate. RNA-seq analysis of the subarachnoid cyst bladder wall compared to the bladder wall and scolex of the vesicular cyst revealed that the subarachnoid form exhibits activation of signaling pathways that promote proliferation and increased lipid metabolism. These adaptions allow growth in a nutrient-limited cerebral spinal fluid. In addition, we identified therapeutic drug targets that would inhibit growth of the parasite, potentially increase effectiveness of treatment, and shorten its duration.

A case-based review on the neuroendoscopic management of intraventricular and subarachnoid basal neurocysticercosis

OBJECTIVE

Extraparenchymal localization of neurocysticercosis (NCC) is rare in non-endemic areas. A case of mixed (intraventricular, IV, and subarachnoid basal, SAB) NCC was surgically treated using the neuroendoscope and a systematic review of the literature was performed with the aim to analyze the use of this instrument in the management of the extraparenchymal forms of the parasitic disease.

MATERIALS AND METHODS

Medline and Embase databases were searched for studies where the neuroendoscope was used for the management of IV/SAB NCC cysts, either for the cerebrospinal fluid diversion or cyst removal. Cyst location, complete removal, cyst breakage during removal, intraoperative and postoperative complications, administration of antihelmintic therapy, outcome and follow-up period were extracted from the articles.

RESULTS

281 patients were treated by means of the neuroendoscope. 254 patients who were described in retrospective cohort studies, came all from endemic areas, with no significant difference between sexes. Mean age at surgery was 30.7 years. Of all cysts reported in retrospective studies, 37.9% were located in the fourth ventricle. An attempt of cyst removal was described in the 84.6% of cases and an endoscopic third ventriculostomy was performed in another 76.4%. A small number of complications were reported intraoperatively (9.1%) obtaining, but a good recovery was achieved at follow-up. Only 17 ventriculoperitoneal shunts were placed after the first procedure, defining a low risk of postoperative hydrocephalus even in case of partial cyst removal.

CONCLUSION

Neuroendoscopic removal of an extraparenchymal NCC cyst is a safe procedure that should be preferred for lateral and third ventricle localization and, in a specialized centre, even for a localization in the fourth ventricle if feasible. It is also efficient because of the possibility of performing an internal CSF diversion concomitantly to cyst removal, avoiding the complication registered with VPS. The need for cysticidal treatment after surgery should be addressed in a prospective study.

Beyond the acute phase: a comprehensive literature review of long-term sequelae resulting from infectious diseases

Infectious diseases have consistently served as pivotal influences on numerous civilizations, inducing morbidity, mortality, and consequently redirecting the course of history. Their impact extends far beyond the acute phase, characterized by the majority of symptom presentations, to a multitude of adverse events and sequelae that follow viral, parasitic, fungal, or bacterial infections. In this context, myriad sequelae related to various infectious diseases have been identified, spanning short to long-term durations. Although these sequelae are known to affect thousands of individuals individually, a comprehensive evaluation of all potential long-term effects of infectious diseases has yet to be undertaken. We present a comprehensive literature review delineating the primary sequelae attributable to major infectious diseases, categorized by systems, symptoms, and duration. This compilation serves as a crucial resource, illuminating the long-term ramifications of infectious diseases for healthcare professionals worldwide. Moreover, this review highlights the substantial burden that these sequelae impose on global health and economies, a facet often overshadowed by the predominant focus on the acute phase. Patients are frequently discharged following the resolution of the acute phase, with minimal long-term follow-up to comprehend and address potential sequelae. This emphasizes the pressing need for sustained vigilance, thorough patient monitoring, strategic health management, and rigorous research to understand and mitigate the lasting economic and health impacts of infectious diseases more fully.

Can sPD-1 and sPD-L1 Plasma Concentrations Predict Treatment Response among Patients with Extraparenchymal Neurocysticercosis?

Extraparenchymal neurocysticercosis (EP-NC) is a chronic, potentially life-threatening disease that responds poorly to initial anthelmintic drug therapy. A depressed specific reactivity of peripheral lymphocytes and an increased level of specific Tregs accompanies EP-NC. The immune checkpoint pathway PD-1 and its ligand PD-L1 downregulates effector T cells, causing specific immune suppression in chronic diseases. This study explored whether their soluble forms, sPD-1/sPD-L1, are present in plasma among patients with EP-NC and if their levels could be associated with treatment response. A total of 21 patients with vesicular EP-NC and 22 healthy controls were included. Patients received standard treatment and were followed for six months to assess treatment response by assessing changes in cyst volume determined with 3D MRI. The presence of both sPD-1 and sPD-L1 was more frequently detected among patients with EP-NC than in healthy controls and had higher concentrations. Among patients, higher pre-treatment levels of both markers were associated with a poor treatment response, and the sensitivity and specificity of the sPD-1/sPD-L1 ratio for predicting any response to treatment were high. Our results are consistent with the presence of lymphocyte exhaustion and open new research perspectives to improve the prognosis of patients with this severe disease.

Troublemaking Lesions: Spinal Tumor Mimics

There are various mass-like lesions that can mimic true neoplasms in the spine, including inflammatory, infectious, vascular, congenital, and degenerative etiologies. While some lesions have distinctive imaging features that suggest a correct diagnosis, others have overlapping characteristics that do not allow their differentiation based solely on their imaging findings. For entities with nonspecific imaging features, knowledge of the clinical and laboratory information is critical to provide an accurate diagnosis.

Older Age in Subarachnoid Neurocysticercosis Reflects a Long Prepatent Period

Patients with subarachnoid neurocysticercosis (NCC) are usually older than those with parenchymal disease. Whether this difference reflects a prolonged presymptomatic period or a delay in diagnosis is not clear. From 408 eligible patients, we retrospectively compared the age at symptom onset in 140 patients diagnosed with parenchymal (pure viable or pure calcified) and subarachnoid NCC who had a confirmatory image available not more than 2 years after the beginning of symptoms. Patients with mixed (parenchymal and subarachnoid) NCC or those with parenchymal cysts at different stages (viable and/or degenerating and/or calcified) were not included. After controlling by sex and residence in rural endemic regions, the mean age at symptom onset in patients with subarachnoid disease was 13.69 years older than those with viable parenchymal disease. A long incubation period is a major contributing factor to older age at presentation in subarachnoid NCC, independent of delayed diagnosis or access to care.

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.

Spinal Arachnoiditis in Patients with Coccidioidomycosis Meningitis-Analysis of Clinical and Imaging Features

Background: Coccidioidomycosis meningitis (CM) is the most aggressive form of coccidioidomycosis, requiring lifelong antifungal treatment and often cerebrospinal fluid (CSF) diversion. Long-standing CM can be associated with spinal complications such as arachnoiditis. However, studies describing the frequency, clinical, and imaging characteristics of arachnoiditis in patients with CM are limited. Methods: We identified 133 patients with CM based on CSF culture, PCR, or serology between January 2010 and December 2020. Of these, 37 patients underwent spinal imaging. Data on demographics, risk factors, symptoms, antifungal therapy, surgical management, follow-up visits, adherence, serological trends, and imaging findings were reviewed. Results: Abnormal findings were observed in 30 of the 37 patients with CM who underwent spinal imaging. The imaging abnormalities noted in our study included leptomeningeal enhancement (53%), arachnoiditis (53%), syringomyelia (23%), cord signal abnormalities (10%), and osteomyelitis (7%). Of the 30 patients, 90% had symptoms, such as weakness, numbness, or urinary retention. The incidence of arachnoiditis in the present study was 12%. Higher initial CSF protein levels and intra cranial pressure were associated with a higher risk of developing arachnoiditis/syringomyelia. Management of CM was challenging, as evidenced by shunt failure (46%), medication non-compliance (57%), and lack of adequate follow-up (60%). Persistent disabilities were noted in 62% of the patients. Conclusions: Patients with CM develop spinal complications such as arachnoiditis, or syringomyelia. Many cases may go undetected due to lack of symptoms in early stages. CM management challenges such as shunt failure, lack of follow-up care, and medication noncompliance, were frequent.

Spinal arachnoiditis and syringomyelia: Review of literature with emphasis on postinfectious inflammation and treatment

Background:

Arachnoiditis refers to chronic inflammation of the arachnoid mater and subarachnoid space due to three major etiologies: chemical, mechanical, and postinfectious. As a rare disease with variable symptomatology and severity at presentation, arachnoiditis can be extremely debilitating with many complications, prominent among which is syringomyelia.

Methods:

We reviewed current literature concerning postinfectious spinal arachnoiditis and associated syringomyelia with emphasis on the treatment options that have been used to date and discuss their respective benefits and drawbacks.

Results:

It is critical to understand the natural history and potential complications of patient with postinfectious arachnoiditis. Surgical and medical treatments both have their own merits and demerits. Different surgical approaches have been employed with variable success rates.

Conclusion:

At present, no consensus exists regarding management of these patients due to the variable nature of the disease that affects treatment efficacy; however, surgical intervention in selected cases may be beneficial.

The returned traveler with neurologic manifestations: could my patient have a parasite?

PURPOSE OF REVIEW

The present review focuses on parasitic infections of the central nervous system (CNS) that can affect the international traveler.

RECENT FINDINGS

The epidemiology of imported parasitic infections is changing and clinicians are treating increasing numbers of returned travelers with parasitic infections in the CNS with which they are not familiar.

SUMMARY

The epidemiology, life cycle, clinical manifestations, diagnosis, and treatment of parasites that affect the CNS will be discussed.

Neurocysticercosis. A frequent cause of seizures, epilepsy, and other neurological morbidity in most of the world

Neurocysticercosis is endemic in most of the world and in endemic areas it accounts for approximately 30% of cases of epilepsy. Appropriate diagnosis and management of neurocysticercosis requires understanding the diverse presentations of the disease since these will vary in regards to clinical manifestation, sensitivity of diagnostic tests, and most importantly, therapeutic approach. This review attempts to familiarize tropical neurology practitioners with the diverse types of neurocysticercosis and the more appropriate management approaches for each.