Single small enhancing computed tomographic (CT) lesions in Indian patients with new-onset seizures. A prospective follow-up in 75 patients

Frequency and Determinant Factors for Calcification in Neurocysticercosis

BACKGROUND

Neurocysticercosis is a major cause of acquired epilepsy. Larval cysts in the human brain eventually resolve and either disappear or leave a calcification that is associated with seizures. In this study, we assessed the proportion of calcification in parenchymal neurocysticercosis and risk factors associated with calcification.

METHODS

Data for 220 patients with parenchymal NCC from 3 trials of antiparasitic treatment were assessed to determine what proportion of the cysts that resolved 6 months after treatment ended up in a residual calcification at 1 year. Also, we evaluated the risk factors associated with calcification.

RESULTS

The overall proportion of calcification was 38% (188/497 cysts, from 147 patients). Predictors for calcification at the cyst level were cysts larger than 14 mm (risk ratio [RR], 1.34; 95% confidence interval [CI], 1.02-1.75) and cysts with edema at baseline (RR, 1.39; 95% CI, 1.05-1.85). At the patient level, having had more than 24 months with seizures (RR, 1.25; 95% CI, 1.08-1.46), mild antibody response (RR, 1.14; 95% CI, 1.002-1.27), increased dose albendazole regime (RR, 1.26; 95% CI, 1.14-1.39), lower doses of dexamethasone (RR, 1.36; 95% CI, 1.02-1.81), not receiving early antiparasitic retreatment (RR, 1.45; 95% CI, 1.08-1.93), or complete cure (RR, 1.48; 95% CI, 1.29-1.71) were associated with a increased risk of calcification.

CONCLUSIONS

Approximately 38% of parenchymal cysts calcify after antiparasitic treatment. Some factors associated with calcification are modifiable and may be considered to decrease or avoid calcification, potentially decreasing the risk for seizure relapses.

Recurrent Neurocysticercosis: Not So Rare

Background

Solitary cysticercus granuloma (SCG) appearing as a single ring-enhancing lesion (SREL) is the most frequently encountered imaging finding in patients of neurocysticercosis (NCC) in India and during follow-up, most of SCGs resolve with or without calcifications. Recurrent SCG have been rarely reported.

Objectives

The aim of our study is to report the incidence of recurrent SCG in a cohort of patients with SCG and postulate the hypothesis.

Materials and methods

This retrospective study included 278 patients with SCG meeting the criteria of NCC. Their medical records and imaging studies were analyzed.

Results

Out of 278 patients, 119 patients with SCG meeting the criteria of NCC with follow-up imaging were included. 15 (12.61%) had recurrent NCC and 104 (87.4%) patients did not have any recurrence during a median follow-up of 14.23 months (range; 0.24 - 113.3) and 25.26 months (range; 3.09- 98.11) respectively. Out of 15 recurrent NCC cases, ten patients had documented imaging resolution or partial regression of previous lesion followed by occurrence of new SCG in the same location, three patients had change in morphology of lesion from solitary discrete REL to solitary conglomerate REL secondary to development of new cysticercus granuloma adjacent to old lesion patients had recurrent lesions adjacent to previous lesion and two patients had new SCG in different locations following regression of old SCGs.

Conclusion

Recurrent SCGs are not uncommon in NCC and recurrence is more likely to occur at the site of initial infection and therefore may be mistaken for persistent infection or other granulomatous lesions.

Clinical presentation of neurocysticercosis-related epilepsy

Neurocysticercosis (NCC) is the most common parasitic infection of the central nervous system and a major risk factor for seizures and epilepsy. Seizure types in NCC vary largely across studies and seizure semiology is poorly understood. We discuss here the studies regarding seizure types and seizure semiology in NCC, and examine the clinical presentation in patients with NCC and drug-resistant epilepsy. We also provide evidence of the role of MRI and EEG in the diagnosis of NCC-related epilepsy. Focal seizures are reported in 60-90% of patients with NCC-related epilepsy, and around 90% of all seizures registered prospectively are focal not evolving to bilateral tonic-clonic seizures. A great number of cases suggest that seizure semiology is topographically related to NCC lesions. Patients with hippocampal sclerosis and NCC have different clinical and neurophysiological characteristics than those with hippocampal sclerosis alone. Different MRI protocols have allowed to better differentiate NCC from other etiologies. Lesions' stages might account on the chances of finding an interictal epileptiform discharge. Studies pursuing the seizure onset in patients with NCC are lacking and they are specially needed to determine both whether the reported events of individual cases are seizures, and whether they are related to the NCC lesion or lesions. This article is part of a Special Issue entitled "Neurocysticercosis and Epilepsy".

Isolated brainstem tuberculomas

BACKGROUND

Isolated brainstem tuberculomas are rare lesions and account for up to 5% of all intracranial tuberculomas in endemic areas. The difficulties in diagnosis and management of this condition are sparsely reported. The aim of this study is to illustrate the nuances in managing brainstem tuberculomas, define prognosis, and demonstrate a shift in management strategies with newer imaging modalities.

METHOD

A retrospective review of 14 patients diagnosed and treated with a diagnosis of 'isolated brainstem tuberculoma' between 2011 and 2015 was done. Diagnosis was made after combining the findings at clinical history, examination, as well as imaging features. Patients were treated with steroids for 6 weeks or until they made a meaningful clinical recovery, and antitubercular therapy (ATT) for a minimum of 18 months or until there was resolution of the tuberculoma. Confirmation of tubercular pathology was done by observing if response to treatment resulted in clinical improvement, which happened in all of our cases.

RESULTS

Mean age at diagnosis was 24.7 years and nine were males. Twelve patients had a combination of cranial nerve deficits with pyramidal weakness or sensory symptoms. Mean duration of symptoms was 4.7 months and tests for human immunodeficiency virus (HIV) infection were negative in all patients. Only two patients had a previous history of tubercular meningitis. Most lesions were located in the pons with size ranging from 1 to 22.2 cm³. Eight patients showed complete resolution of the lesion at latest follow-up and the rest were still on ATT. Mean duration of ATT received for resolution of the lesion was 22 months. Almost all of our patients improved clinically on steroids and ATT.

CONCLUSIONS

Intracranial tuberculomas may present with or without meningitis. A high index of suspicion is essential, especially in endemic areas. A combination of clinical symptoms, investigations, and imaging features help in coming to a diagnosis. Biopsy of a brainstem lesion is fraught with complications. Antitubercular therapy has a very good prognosis, though the duration of therapy required may be longer.

Natural course of typical and atypical parenchymal solitary cysticercus granuloma of the brain: a 3-year prospective clinico-radiological study

OBJECTIVE

To evaluate the role of advanced magnetic resonance (MR) sequences (fast imaging employing steady-state acquisition (FIESTA), T2 star-weighted angiography (SWAN) and spoiled gradient recalled echo (SPGR)) in patients with single small enhancing computed tomography lesions and scolex demonstration in typical and atypical parenchymal neurocysticercosis.

METHODS

In this study, 59 patients of new-onset seizures with single small enhancing computed tomography lesions of the brain were included. Along with routine MR sequences, advanced MR sequences, like SWAN, FIESTA, and pre and post-contrast SPGR, were performed. Follow-up MR studies focussing on the morphology of the lesions and demonstration of scolex were performed 6 monthly for 3 years.

RESULTS

The majority of patients (62.7%) were men with partial seizure as the most common manifestation. On SPGR, contrast lesions were identified as either 'typical' (42, 71.2%) or 'atypical' (17, 28.8%). In the typical lesion group, SWAN and FIESTA sequences detected scolex in 30 (71.4%) and 32 (76.2%), respectively. The combination of SPGR-contrast, FIESTA and SWAN sequences detected scolex in 35 (83.3%) patients compared to 19 (45.2%) by routine sequences (P < 0.001). In the atypical lesion group, SWAN and FIESTA sequences detected scolex in 15 (88.2%) and 16 (94.1%) patients, respectively. The combination of SPGR-contrast, FIESTA and SWAN sequences detected scolex in 16 (94.1%) patients compared to 10 (58.8%) by routine sequences (P < 0.001). Follow-up showed greater resolution with lesser calcification in the typical group compared to the atypical group.

CONCLUSION

This study provides an insight into the natural course of typical and atypical solitary cysticercus granuloma lesions, and the utility of SPGR-contrast, FIESTA and SWAN MR sequences in scolex demonstration and identification of atypical lesions.

Managing neurocysticercosis: challenges and solutions

Taenia solium neurocysticercosis (NCC) is a major cause of neurological morbidity in the world. Variability in the neuropathology and clinical presentation of NCC often make it difficult to diagnose and manage. Diagnosis of NCC can be challenging especially in endemic and resource-limited countries where laboratory and imaging techniques are often lacking. NCC management can also be challenging as current treatment options are limited and involve symptomatic agents, antiparasitic agents, or surgery. Although antiparasitic treatment probably reduces the number of active lesions and long-term seizure frequency, its efficacy is limited and strategies to improve treatment regimens are warranted. Treatment decisions should be individualized in relation to the type of NCC. Initial measures should focus on symptomatic management, with antiparasitic therapy only to be considered later on, when appropriate. Symptomatic treatment remains the cornerstone in NCC management which should not only focuses on epilepsy, but also on other manifestations that cause considerable burden (recurrent headaches, cognitive decline). Accurate patients’ categorization, better antiparasitic regimens, and definition of new clinical outcomes for trials on NCC could improve management quality and prognosis of NCC. Prevention strategies targeting tapeworm carriers and infected pigs are yielding good results in local models. If local elimination of transmission is confirmed and replicated, this will open the door to cysticercosis eradication efforts worldwide.

Calcified neurocysticercosis lesions and antiepileptic drug-resistant epilepsy: a surgically remediable syndrome?

PURPOSE

In contrast to the well-recognized association between acute symptomatic seizures and neurocysticercosis, the association between antiepileptic drug (AED)-resistant epilepsy and calcified neurocysticercosis lesions (CNLs) is poorly understood. We studied the association between AED-resistant epilepsy and CNLs, including the feasibility and outcome of resective surgery.

METHODS

From the prospective database maintained at our epilepsy center, we reviewed the data of all patients with AED-resistant epilepsy who underwent presurgical evaluation from January 2001 to July 2010 and had CNL on imaging. We used clinical, neuroimaging, and interictal, ictal, and intracranial electroencephalography (EEG) findings to determine the association between CNL and epilepsy. Suitable candidates underwent resective surgery.

KEY FINDINGS

Forty-five patients fulfilled the inclusion criteria. In 17 patients, CNL was proven to be the causative lesion for AED-resistant epilepsy (group 1); in 18 patients, CNL was associated with unilateral hippocampal sclerosis (HS; group 2); and in 10 patients, CNLs were considered as incidental lesions (group 3). In group 1 patients, CNLs were more common in frontal lobes (12/17), whereas in group 2 patients, CNLs were more commonly located in temporal lobes (11/18; p = 0.002). Group 2 patients were of a younger age at epilepsy onset than those in group 1 (8.9 ± 7.3 vs. 12.6 ± 6.8 years, p = 0.003). Perilesional gliosis was more common among patients in group 1 when compared to group 3 patients (12/17 vs. 1/10; p = 0.006). Fifteen patients underwent resective surgery. Among group 1 patients, four of five became seizure-free following lesionectomy alone. In group 2, four patients underwent anterior temporal lobectomy (ATL) alone, of whom one became seizure-free; five underwent ATL combined with removal of CNL (two of them after intracranial EEG and all of them became seizure-free, whereas one patient underwent lesionectomy alone and did not become seizure-free.

SIGNIFICANCE

In endemic regions, although rare, CNLs are potential cause for AED-resistant and surgically remediable epilepsy, as well as dual pathology. Presence of perilesional gliosis contributes to epileptogenicity of these lesions. For those patients with CNL and HS, resection of both lesions favors better chance of seizure-free outcome.

Neurocysticercosis in sub-Saharan Africa: a review of prevalence, clinical characteristics, diagnosis, and management

Neurocysticercosis has been recognized as a major cause of secondary epilepsy worldwide. So far, most of the knowledge about the disease comes from Latin America and the Indian subcontinent. Unfortunately, in sub-Saharan Africa the condition was neglected for a long time, mainly owing to the lack of appropriate diagnostic tools. This review therefore focuses on the prevalence of neurocysticercosis in sub-Saharan Africa, the clinical picture with emphasis on epilepsy, as well as the diagnosis and treatment of neurocysticercosis and its related epilepsy/epileptic seizures in African resource-poor settings.

Cysticerci-related single parenchymal brain enhancing lesions in non-endemic countries

OBJECTIVE

Review of case reports and case series of patients with single cysticercus granulomas in non-endemic countries to determine the characteristics of this form of neurocysticercosis in these regions.

METHODS

MEDLINE and manual search of patients with single cysticercus granulomas diagnosed in non-endemic countries from 1991 to 2011. Abstracted data included: demographic profile, clinical manifestations, form of neurocysticercosis, and whether the disease occurred in immigrants, international travelers, or citizens from non-endemic countries who had never been abroad.

RESULTS

A total of 77 patients were found. Of these, 61 (79%) were diagnosed since the year 2000. Thirty-four patients (44%) patients were immigrants from endemic countries, 18 (23%) were international travelers returning from disease-endemic areas, and the remaining 25 (33%) were citizens from non-endemic countries who had never been abroad. Most immigrants and international travelers became symptomatic two or more years after returning home. Countries with the most reported patients were Kuwait (n=18), UK (n=11), Australia (n=8), USA (n=7), Japan (n=6), and Israel (n=5).

CONCLUSIONS

A single cerebral cysticercus granuloma in a non-endemic country is not a rare event. As seen in endemic regions, these cases have a good prognosis although more surgical procedures are performed in non-endemic countries, likely reflecting a decrease of diagnostic suspicion for cysticercosis and an increased availability of surgical options. The mean age of the reported cases was 25 years, and immigrants most often developed the disease greater than two years after arrival into a non-endemic area, suggesting a significant delay between infection and symptoms. However, some may have been infected and developed the disease while residing in non-endemic countries.

Neurocysticercosis: unraveling the nature of the single cysticercal granuloma

A single enhancing lesion in the brain parenchyma, also called an inflammatory granuloma, is a frequent neurologic diagnosis. One of the commonest causes of this lesion is human neurocysticercosis, the infection by the larvae of the pork tapeworm, Taenia solium. Following the demonstration that viable cysticercosis cysts survive in good conditions for several years in the human brain, single cysticercal granulomas have been consistently interpreted as representing late degeneration of a long-established parasite. On the basis of epidemiologic, clinical, and laboratory evidence detailed in this article, we hypothesize that in most cases these inflammatory lesions correspond to parasites that die in the early steps of infection, likely as the natural result of the host immunity overcoming mild infections.

Non contrast-enhanced four-detector multisection CT for the detection of ring lesions in seizures

AIM

To evaluate the role of non contrast-enhanced multidetector computed tomography (MDCT) in the detection of ring lesions in the brain in patients from the Indian subcontinent, presenting with seizures.

MATERIALS AND METHODS

Ninety-four patients presenting with seizures were examined using four-detector MDCT. Contiguous axial non contrast-enhanced CT of the brain was performed with a section width/section collimation of 5mm/5mm. A single axial non-contrast enhanced examinaton of section width 2.5mm was obtained through the region of interest, if necessary. This was followed by contrast-enhanced sequential imaging in all patients, using the same parameters as for unenhanced CT (i.e., 5mm/5mm). Non-contrast and contrast-enhanced CT images were recorded and reviewed separately.

RESULTS

In 63 out of 94 cases non-enhanced MDCT (with section width 5mm) was able to identify the ring lesions. In 11 cases, which were doubtful on unenhanced CT (5mm), performing a single examination using a section width of 2.5mm through the area of interest, helped to detect the ring lesion. Hence in 74 out of 94 (79%) cases ring lesions could be detected using unenhanced MDCT. In the remaining 21% cases, the presence of ring lesions in the brain was confirmed only after the intravenous administration of contrast medium.

CONCLUSION

Non contrast-enhanced MDCT is recommended for detecting ring lesions in the brain of patients on the Indian subcontinent, presenting with seizures. This can help to decrease the radiation dose to the patient and reduce the duration of examination. The risk of adverse reactions and patient discomfort associated with intravenous contrast medium injection are also reduced as are the costs incurred. Contrast-enhanced MDCT should be performed only in those cases in which the presence of ring lesions is doubtful on unenhanced CT.

Intravenous methyl prednisolone in patients with solitary cysticercus granuloma: A random evaluation

PURPOSE

To evaluate the role of intravenous methyl prednisolone in patients with solitary cysticercus granuloma with new-onset seizures.

METHODS

In this open-label, randomized, prospective, follow-up study, 52 patients with new-onset seizures and a single enhancing CT lesion of cysticercus were randomly divided in two groups to receive either intravenous methyl prednisolone for 5 days along with antiepileptic drug (n=25) or antiepileptic drug monotherapy (n=27) alone. The patients were followed up for at least for 9 months. Repeat CT scans were performed after 2 months.

RESULTS

After 2 months, lesion disappeared in 60% patients of intravenous methyl prednisolone group and 18.5% patients receiving only antiepileptic drug (p=0.001). As far as seizure recurrence was concerned, a lower number (16% versus 33%) of intravenous methyl prednisolone treated patient had recurrence, the difference was insignificant.

CONCLUSION

Intravenous methyl prednisolone therapy helps in early resolution of solitary cysticercus granuloma.

Single enhancing computerized tomography-detected lesion in immunocompetent patients

Single enhancing computerized tomography (CT)-documented lesions may occur in several infectious and neoplastic diseases of the central nervous system and are the most common radiological abnormality seen in patients with acute-onset seizures in India and many other developing countries. Similar CT-documented lesions have also been reported in the developed world where these lesions are often considered to be caused by neoplasms or tuberculoma. Histopathological studies in India and even in some developed countries revealed that neurocysticercosis (NCC) is the most likely cause of these lesions provided they fulfill a rigid set of clinical and radiological criteria. Single cysticercus granuloma measures less than 20 mm in diameter, may be associated with cerebral edema not severe enough to produce midline shift, and occur in patients with seizures, normal neurological status, and no evidence of active systemic disease. When these lesions resolve spontaneously, either disappearing or changing into a calcified nodule, the diagnosis of NCC is very likely. The second most common cause of these CT-detected lesions is tuberculoma; in patients with these lesions similar clinical and neuroimaging features are also present. Few authors believe that in poor and developing countries, where both tuberculosis and NCC are common, it is difficult to differentiate between tuberculoma and a single cysticercal granuloma. The most interesting feature of these solitary enhancing lesions is their spontaneous disappearance within weeks or months. Some lesions "heal" by becoming calcified. These patients require only antiepileptic therapy, and this medication may be withdrawn safely after the lesion has resolved on CT scanning. In several studies provision of anticysticercal drugs has been attempted, but because of conflicting results, their role in the management of these single lesions is uncertain. Neurosurgeons have a very limited role to play. In very rare situations, if the lesion increases in size and if focal neurological deficits manifest or seizures are uncontrolled, a brain biopsy sample may be required and histopathological evaluation performed to establish the correct diagnosis.