Clinical implications of calcified lesions of neurocysticercosis

Clinical characteristics of migraine in patients with calcified neurocysticercosis

BACKGROUND

Patients with neurocysticercosis (NCC) may have an increased frequency of migraine. We studied the characteristics of migraine attacks in patients with calcified NCC on brain imaging.

METHODS

Of 350 migraine patients who visited our outpatient department from January 2016 through June 2018, 166 had undergone brain imaging. Seventy-two patients with migraines had calcified NCC. The migraine attacks of the patients with calcification (MiC) were compared with those of 94 patients without calcification (MiNC).

RESULTS

Side-locked headaches were seen in 48.6% of the MiC patients. Aura preceding the migraine attack was more common in the MiC group than in the MiNC group (22.22% vs 7.4%; p=0.001). The MiC group had fewer headache episodes per month (5 vs 6; p<0.0001) with fewer common associated features (62.5% vs 84.1%; p=0.006). They also required fewer drugs for secondary prophylaxis (2 vs 3; p=0.002).

CONCLUSIONS

Some of the clinical characteristics of migraine attacks are sufficiently different in patients with and without NCC. This may suggest some influence of NCC in the pathophysiology of migraine to account for alterations in the clinical manifestations of the disease. Whether this difference could be inferred as NCC having a causative role in migraine needs further research.

An Ambispective Cohort Study to Assess Seizure Recurrences in Children with Calcified Parenchymal Neurocysticercosis

Calcified neurocysticercosis (NCC), previously thought to be a dead end, is an important risk factor for seizure recurrences. We studied the pattern of seizure recurrences and associated radiological findings in children with calcified NCC. In this ambispective cohort study, we enrolled children (age 1-15 years) with calcified NCC attending the pediatric NCC clinic between January 2017 and December 2017. Retrospective data were collected from the hospital records, and all enrolled children were prospectively followed up till June 2018. The study group divided into two groups: 1) children first presenting with calcified granuloma and 2) children presented with ring-enhancing lesion (REL) and transformed into the calcified lesion during follow-up imaging. During the study period (January 2017-December 2017), 520 children with NCC were screened and 128 with calcified NCC were enrolled. The mean age was 10.8 ± 3.2 years, and 63% were boys. Among 128 children, 40 (31%) had calcified granuloma and 88 (69%) had REL transformed to calcified granuloma. Sixty-one (49%) children had seizure recurrence: 22 (58%) within calcified granuloma group and 39 (45%) within REL transformed to calcified granuloma group (P = 0.18). Seizure recurrence was associated with the presence of perilesional edema (PE) in 35 (57.4%) children on computed tomography scan. The median interval between two seizure recurrences was 30 (17-56) months, and the median antiepileptic drug-free interval was 17 (12-22) months. The total duration of continued seizures was 42 (26-58) months, slightly longer in children with REL transformed to calcified granuloma group (42, 95% CI: 18-66 months) in comparison to calcified granuloma group (35, 95% CI: 10-60 months, P = 0.32). To conclude, children with calcified NCC have seizure recurrences over a prolonged period. Seizure recurrences are intermittent and may be interspersed with a prolonged period of quiescence in between. The presence of PE and contrast enhancement around the lesion during seizure recurrence suggests lesion reactivation.

Natural History of Patients With Perilesional Edema Around Taenia solium Calcified Granulomas

Background

The transient development of perilesional edema (PE) around ≥1 calcification (defined as 1 episode) occurs in about 50% of the patients with recurrent seizures in calcified neurocysticercosis (NCC). We determined the long-term clinical and radiological course of persons undergoing PE episodes.

Methods

Twenty-one persons with NCC who experienced ≥1 PE episode were followed for a median of 10.6 years (range, 0.4-29.2 years). Clinical evaluations and magnetic resonance imaging (MRI) were performed at the time of suggestive symptoms and during routine follow-up.

Results

PE episodes were documented 78 times, involving 50 of 729 calcifications. Episodes reoccurred in all but 3 persons. The pattern, rate, and number of episodes were variable, commonly chronic, and not significantly associated with time from treatment, number of calcifications, or sex. Seizure was the most common symptom, but almost 30% of episodes were asymptomatic and detected by MRI during routine follow-up. Persons with delayed recurrent episodes were significantly older (age, 42.3 vs 28.8 years; P = .045). Seizures continued to occur in 37.5%, and 2 persons had a severe disabling clinical course.

Conclusions

The number and timing of PE episodes in individuals with calcified NCC are variable and commonly chronic, sometimes recurring over decades. A minority of patients developed significant disability.

Disease Centered Around Calcified Taenia solium Granuloma

Taenia solium (the pork tapeworm) is present in most developing countries, where it is a frequent cause of seizures and other neurological disease. Parasitic larvae invade the human brain, establish, and eventually resolve, leaving a calcified scar. While these lesions are common in endemic regions, and most of these are clinically silent, a proportion of individuals with calcified cysticerci develop seizures from these lesions, and 30-65% of these cases are associated with perilesional edema (PE), likely due to host inflammation. This manuscript summarizes the importance, characteristics, natural history, and potential prevention and treatments of symptomatic calcified neurocysticercosis (NCC).

Calcified neurocysticercus, perilesional edema, and histologic inflammation

Abstract. Here, we present the second report of the histopathology of a Taenia solium calcification giving rise to perilesional edema. This has important implications, because if perilesional edema lesions are inflammatory in character, immunosuppressive or anti-inflammatory medications, not just antiepileptic drugs alone, may be useful to prevent or treat recurring episodes in such patients.

Corticosteroid withdrawal precipitates perilesional edema around calcified Taenia solium cysts

Calcified Taenia solium granulomas are the focus of repeated episodes of perilesional edema and seizures in 50% of persons with calcifications, history of seizures, and a positive serology for cysticercosis. The pathophysiology is unclear but recent studies suggest the edema is caused by inflammation. We report two new cases and four other published cases where cessation of corticosteroids appeared to result in recurrence or new appearance of perilesional edema around calcifications. This suggests that perilesional edema is an immune-mediated phenomenon.

Edema surrounding calcified intracranial cysticerci: clinical manifestations, natural history, and treatment

Calcified granulomas are the most common radiological finding in neurocysticercosis (10-20% of endemic populations). A small proportion serves as foci of seizure activity, which results in large numbers of persons with epilepsy. Calcified granulomas are not all the same. Some demonstrate blood-brain barrier dysfunction (magnetic resonance imaging enhancement) most likely due to the presence of inflammation, visualizable scolices, and/or gliosis. About half the patients with a recent history of seizures, positive serology, and only calcified lesions develop perilesional edema at the time of a seizure recurrence. The natural history, treatment, and pathophysiology of this phenomenon are not well studied. Episodes are usually associated with seizures or other neurological manifestations, resolve by 4-6 weeks, sometimes occur repeatedly, and usually involve a subset of the same calcifications. Treatment is supportive. Histopathological examination of one calcification associated with multiple perilesional edema episodes revealed significant inflammation and supports the concept that perilesional edema is inflammatory in nature. This most likely is due to host responses to released or newly recognized parasite antigen and/or upregulation of the host immune response. Immunosuppressive and anti-inflammatory agents may be useful in prevention and/or treatment of this phenomenon.

Calcified neurocysticercosis among patients with primary headache

Background: Anecdotal reports and a single case-control epidemiological survey have suggested an association between the helminthic disease neurocysticercosis and primary headache. The present study was undertaken to determine whether neurocysticercosis is more common among patients with primary headaches than in other neurological disorders.

Methods: We determined the prevalence of neurocysticercosis in a cohort of patients with primary headache who were seen at our institution over a 20-year period. We used as controls all people from the same cohort with four major different categories of neurological disorders, including cerebrovascular disease, degenerative disorders of the CNS, head trauma, and primary brain tumors. We evaluated differences in the prevalence of neurocysticercosis between patients and controls.

Results: Forty-eight of 1017 patients with primary headache and 31 of 1687 controls had neurocysticercosis (4.7% vs 1.8%, p < 0.0001). Calcified parenchymal brain cysticerci were more frequent among patients with primary headache than in those with cerebrovascular disease (4.7% vs 1%, p < 0.001), degenerative disorders of the CNS (4.7% vs 2.4%, p < 0.05), and head trauma (4.7% vs 2.3%, p < 0.05). There were no significant differences, however, for the subset of controls with primary brain tumors (4.7% vs 3.5%), a condition that has also been associated with neurocysticercosis.

Conclusions: There is a relationship between calcified neurocysticercosis and primary headache disorders. It is possible that periodic remodeling of cysticercotic calcifications, with liberation of antigens to the brain parenchyma, contributes to the occurrence of headache in these patients.

Short report: A calcified Taenia solium granuloma associated with recurrent perilesional edema causing refractory seizures: histopathological features

We describe the first detailed histological description of an excised calcified Taenia solium granuloma from a patient who developed recurrent seizures associated with perilesional edema surrounding a calcified cysticercus (PEC). The capsule, around a degenerated cysticercus, contained marked mononuclear infiltrates that extended to adjacent brain, which showed marked astrocytosis, microgliosis, and inflammatory perivascular infiltrates. The presence of large numbers of mononuclear cells supports an inflammatory cause of PEC. Immunosuppression or anti-inflammatory measures may be able to treat and prevent PEC and recurrent seizures.

Diagnosis and treatment of neurocysticercosis

Neurocysticercosis, the infection caused by the larval form of the tapeworm Taenia solium, is the most common parasitic disease of the central nervous system and the most common cause of acquired epilepsy worldwide. This has primarily been a disease that remains endemic in low-socioeconomic countries, but because of increased migration neurocysticercosis is being diagnosed more frequently in high-income countries. During the past three decades improved diagnostics, imaging, and treatment have led to more accurate diagnosis and improved prognosis for patients. This article reviews the current literature on neurocysticercosis, including newer diagnostics and treatment developments.

Perilesional brain oedema and seizure activity in patients with calcified neurocysticercosis: a prospective cohort and nested case-control study

BACKGROUND

Cysticercosis due to Taenia solium is a cause of adult-acquired seizures and epilepsy even in patients with only calcified larval cysts. Transient perilesional brain oedema is seen around the calcified foci but its importance, association with seizures, incidence, and pathophysiology are unknown.

METHODS

110 patients with only calcified lesions and a history of seizures or severe headaches were followed prospectively in a cohort design to assess the incidence of seizure relapse. In a nested case-control substudy, perilesional oedema was assessed by MRI at the time of seizure in symptomatic patients and in matched asymptomatic controls taken from the study population.

FINDINGS

Between November, 1999, and December, 2006, 29 patients had an incident seizure during a median follow up of 32.33 (SD 19.99) months, with an estimated 5-year seizure incidence of 36% (95% CI 25% to 49%). 24 of 29 (83%) patients with seizure relapse had an MRI evaluation within 5 days of the event; perilesional oedema was seen in 12 patients (50%) compared with two (9%) of 23 asymptomatic matched controls.

INTERPRETATION

Perilesional oedema is common and associated with episodic seizure activity in patients with calcified neurocysticercosis. Our findings are probably representative of symptomatic patients in regions where T solium neurocysticercosis is endemic and suggest a unique and possibly preventable cause of seizures in this population.

Calcific neurocysticercosis and epileptogenesis

Neurocysticercosis is responsible for increased rates of seizures and epilepsy in endemic regions. The most common form of the disease, chronic calcific neurocysticercosis, is the end result of the host's inflammatory response to the larval cysticercus of Taenia solium. There is increasing evidence indicating that calcific cysticercosis is not clinically inactive but a cause of seizures or focal symptoms in this population. Perilesional edema is at times also present around implicated calcified foci. A better understanding of the natural history, frequency, epidemiology, and pathophysiology of calcific cysticercosis and associated disease manifestations is needed to define its importance, treatment, and prevention.

Demonstration of scolex within calcified cysticercus cyst: its possible role in the pathogenesis of perilesional edema

PURPOSE

This study was performed to understand the relation between the scolex as demonstrated on gradient echo (GRE) imaging in a calcified cysticercus cyst and the development of perilesional edema that may be of value in understanding the pathogenesis of this entity.

METHODS

Twenty-one patients with solitary calcified lesion on computed tomography (CT), with seizures of recent onset (within 15 days), were selected for this study. All the patients were subjected to magnetic resonance imaging (MRI) including GRE imaging. The patients were grouped on the basis of presence or absence of perilesional edema around the calcified lesion on MRI.

RESULTS

There were 14 patients with perilesional edema, and seven patients had no evidence of edema. Of these 14 patients with perilesional edema, rim enhancement was detected in 13 patients on postcontrast MRI, whereas no enhancement was observed in one patient. The scolex was seen in all these 14 patients on GRE images. Of the seven patients without evidence of edema, the scolex was not seen in any of these patients on GRE imaging. In addition, there was no evidence of any contrast enhancement on postcontrast study in any of the patients in this group.

CONCLUSIONS

We conclude that the calcified cysts with scolex seen on GRE imaging are associated with perilesional edema. This is probably due to preservation of antigenic material in these calcified cysts, the release of which provokes an inflammatory response that may be responsible for the perilesional edema.

Calcified cysticerci provoke perilesional edema and seizures

In cases of cysticercosis, seizures and other symptoms occur in persons with only calcified brain lesions. The presence of perilesional edema has been documented in association with calcified lesions in symptomatic patients, but the frequency of this complication and characteristics of the patients who develop it are not known. Patients in Peru and the United States with neurocysticercosis, documented by positive results of serological testing and with only calcified lesions as shown using computerized tomography, were studied using magnetic resonance imaging. Perilesional edema was observed in slightly more than one-third of the patients, and some patients had frequent, severely disabling episodes. Those with an increased proportion of enhancing calcified lesions were more likely to show perilesional edema. Edema around calcified lesions is common in this population and is associated with seizures and neurological morbidity.