Meningomyelitis in a case of toxocariasis with markedly isolated CSF eosinophilia and an MRI-documented thoracic cord lesion

Aberrant migration of Spirocerca lupi to the spinal cord in dogs: Association of clinical signs, CSF analysis, preventive treatment, and outcome

Spirocerca lupi is a nematode typically targeting the esophageal wall but may also migrate to the spinal cord. This study aimed to characterize the clinical presentation, cerebrospinal fluid (CSF) findings, prognostic factors, and outcomes of dogs with spinal S. lupi (SSL) aberrant migration, and to evaluate prophylactic treatment efficacy. Medical records from 2016 to 2022 were reviewed, including 284 study and 280 control dogs. Complete recovery occurred in 130/284 dogs (46 %) at 1 month, and in 214/284 dogs (75 %) at 3 months and was associated with the clinical grade at presentation (P < 0.001). Of the 162 non-ambulatory dogs, 59 % became ambulatory at 1 month, and 79 % at 3 months. Dogs with urinary incontinence were less likely to fully recover (P = 0.04). Protein CSF concentration was lower at presentation in dogs who completely recovered at 1 month and 3 months (344 mg/dL [15-1297] vs. 732 mg/dL [34-1291], P = 0.006, and 366 mg/dL [15-1297] vs. 769 mg/dL [83-1262], P = 0.025, respectively). A higher proportion of control dogs received prophylactic treatment compared to the SSL group (216/280 [77 %] vs. 168/284 [59 %], respectively, P < 0.001, OR 0.43, CI 0.30-0.62) however, prophylactic treatment did not significantly impact recovery rates. Our findings suggest that SSL is associated with a favorable prognosis; however, full recovery may take several months, and dogs presenting with urinary incontinence and higher neurological severity grades are less likely to recover. Finally, our findings suggest that prophylactic treatment against S. lupi may have a protective effect against SSL and is therefore recommended in endemic regions.

Clinical spectrum of symptoms in cerebral Toxocariasis (Review)

Human helminth zoonosis is one of the most encountered helminthiases worldwide. Representative diseases include Toxocara canis and Toxocara cati, which are common nematodes prevalent in dogs and cats. The infiltration of these roundworms in the human body through contaminated food or nematode eggs could lead to central nervous system injury as the roundworms can cross the blood-brain barrier leading to neurotoxocariasis. Among the neurological and neuropsychological disturbances produced by Toxocara infection, in humans, the most representative are meningitis, encephalitis, myelitis and cerebral vasculitis, but asymptomatic central nervous system infection is probably the most prevalent. The present review examines the clinical symptomatology of neurotoxocariasis in case reports in the literature in the last 7 decades (1950-2020). The available evidence was retrieved from PubMed and Medline electronic databases. The present review reports the most prevalent clinical symptomatology in the cases of detected and diagnosed Toxocara infection with neuroinvasion. Thus, the present review aims to raise the awareness of neurological cases of Toxocara infection with the potential to at least establish differential diagnosis of neurotoxocariasis.

Toxocariasis of the Nervous System

PURPOSE

Toxocariasis is a helminthozoonosis caused by the infection of a human host by the larva of Toxocara spp., predominately involving Toxocara canis and Toxocara cati, which are common nematodes in dogs and cats, respectively. Human transmission occurs through contact with animals or by consumption of food contaminated with parasite's eggs. The purpose of this article is to review the current knowledge regarding human neurotoxocariasis.

METHODS

We conducted a systematic review of the existing literature concerning toxocariasis of the nervous system.

RESULTS

Clinical spectrum of human toxocariasis varies widely from a subclinical course to significant organ morbidity. Clinical course depends on parasitic load, the migration route of the larvae and host response. Human neurotoxocariasis is a relatively rare entity yet associated with severe sequelae. Manifestations include meningitis (usually eosinophilic), encephalitis, myelitis, cerebellar vasculitis, space-occupying lesion, behavioral abnormalities, and optic neuritis. Even though valid diagnostic criteria are lacking, neurotoxocariasis should be suspected in patients with neurologic symptoms and cerebrospinal fluid (CSF) pleocytosis with eosinophilia, positive serology for anti-Toxocara antibodies, in serum and/or CSF, sterile CSF and clinical improvement after antihelminthic treatment. Neurotoxocariasis is treated by benzimidazole components, most frequently albendazole, corticosteroids, or diethylcarbamazine.

CONCLUSION

Parasite larvae migrate through tissues and are able to reach the nervous system causing neurotoxocariasis. Its clinical spectrum varies and includes myelitis, meningoencephalitis, brain abscess, and vasculitis. Neurotoxocariasis should always be suspected in patients with neurologic symptoms accompanied by eosinophilia in blood and/or CSF. Early diagnosis and treatment could prevent long-term neurologic impairment.

Toxocara infection in the differential diagnosis of multiple sclerosis in the Middle East

A critical step in the diagnosis of multiple sclerosis is to rule out a heterogeneous variety of multiple sclerosis mimickers, which is crucial in the era of powerful immune-modulator treatments. In this review, we discuss the background of toxocariasis in general, present central nervous system Toxocara infection as one of the multiple sclerosis mimickers in the Middle East, and share our experience about the diagnosis and management of this condition. This entity seems very relevant in a region such as the Middle East, where displacement of populations and conflict can result in non-hygienic food and water management bundles. The diagnosis should be entertained, especially when assessing patients with myelopathy. The presence of a single lesion in the spinal cord with inflammatory features should prompt serological testing for Toxocara IgG and IgM in serum and the cerebrospinal fluid. This infection is treatable, with the regimen of high-dose albendazole being one of the most accepted treatments. Although most cases exhibit a good prognosis, some have residual deficits localized to the affected spinal cord level.

Clinical and Magnetic Resonance Imaging Findings of Neurotoxocariasis

Human toxocariasis is one of the most prevalent helminthiases worldwide. Toxocara canis larvae can cross the blood-brain barrier leading to the neurotoxocariasis. The clinical presentation consists of a wide spectrum of neurological manifestations, but asymptomatic infection is probably common. Neurotoxocariasis is not a frequent diagnosis probably due to the non-specific nature of its symptoms as well as the lack of confirmatory diagnostic tests. Diagnosis of neurotoxocariasis is based on the presence of a high titer of anti-Toxocara antibody in the cerebrospinal fluid or in the serum, presence of eosinophilia in the serum or cerebrospinal fluid, and clinical and radiological improvement after anthelmintic therapy; however, universally accepted diagnostic criteria are lacking. Magnetic resonance imaging (MRI) findings include single or multiple, subcortical, cortical or white matter hyperintense lesions, best visualized on FLAIR and T2-weighted imaging, and usually isointense or hypointense on T1. These imaging findings are suggestive but not specific to neurotoxocariasis. Definitive diagnosis is made by histological confirmation, but it is rarely followed. This review provides an overview of the clinical manifestations, management options, and MRI findings of neurotoxocariasis.

Toxocara canis myelitis involving the lumbosacral region: a case report

CONTEXT

Toxocara canis is a parasite known to cause visceral larva migrans. The infection rarely affects the central nervous system but there have been several reports of myelitis caused by visceral larva migrans due to Toxocara canis. In previous reported cases, the lesions were located in the thoracic or cervical spinal cord. To the best of our knowledge, this is the first report of a lesion involving the lumbosacral region.

FINDINGS

A 60-year-old man developed weakness and dysesthesia in the lower limbs. The symptoms resolved spontaneously, but recurred after five months. One month later, the patient developed pollakiuria and constipation. He was a dog owner and frequently ate raw chicken meat and beef liver. Sagittal T2-weighted image (T2WI) showed swelling and hyperintensity in the spinal cord from T10 to the lumbosacral region and focal nodular enhancement on the posterior segment of the lumbar spinal cord. Blood cell counts showed slight eosinophilia and elevated serum immunoglobulin E level. Cerebrospinal fluid examination showed slight pleocytosis with eosinophilia. Enzyme-linked immunosorbent assay showed high levels of anti-Toxocara antibodies in the serum and cerebrospinal fluid. In addition, confirmatory test by Western blot was positive. The patient was initially treated with intravenous methylprednisolone with slight improvement in muscle weakness. Albendazole was added with a second course of intravenous methylprednisolone. The muscle weakness in the lower limbs improved considerably, and swelling and hyperintensity on T2WI almost disappeared.

CONCLUSION

Our results suggest that Toxocara canis myelitis cannot be discounted even if the myelitis involves the lumbosacral region.

Neurotoxocariasis: a systematic literature review

PURPOSE

Toxocariasis is a widespread zoonosis, which may result in central nervous system injury.

METHODS

We conducted a systematic literature review in MEDLINE, SciELO, ScienceDirect and Google Scholar up to April 2015 using a combination of the following search terms: "neurotoxocariasis" or "neurotoxocarosis", "toxocariasis" or "toxocarosis" and "cerebral" or "neurologic".

RESULTS

One hundred cases of neurotoxocariasis were identified in literature. The majority of patients were male (58 %), with a median age of 42 years. The predominant clinical pictures were myelitis (60 %), encephalitis (47 %) and/or meningitis (29 %). Fever was inconstant (23 %). The suspected mode of transmission, mentioned in only 49 % of cases, was mainly contact with dogs and/or cats (67 %) and ingestion of contaminated food (31 %). Diagnostic imaging examinations found hypodense lesions in cerebral scanner sequences and hyperintense lesions in cerebral MRI T2-weighted sequences in 65 and 57 % of encephalitis cases respectively, and in 92 % of myelitis cases in medullary MRI T2-weighted sequences. The detection of antibodies against Toxocara spp. was almost constant in blood and cerebrospinal fluid (CSF), 99 and 93 %, respectively. The two most commonly used drugs were corticosteroids (72 %) and/or albendazole (68 %) for a period of at least 3 weeks, which often needed to be repeated. Despite a low mortality rate (6 %), complete remission was observed in only 40 % of cases.

CONCLUSIONS

Neurotoxocariasis, a completely preventable zoonosis, could lead to severe sequelae failing prompt diagnosis. A compatible clinical picture, presence of risk factors, blood eosinophilia and high titers of antibodies against Toxocara spp. in CSF should alert physicians.

Cerebral Toxocariasis: Silent Progression to Neurodegenerative Disorders?

Toxocara canis and T. cati are highly prevalent nematode infections of the intestines of dogs and cats. In paratenic hosts, larvae do not mature in the intestine but instead migrate through the somatic tissues and organs of the body. The presence of these migrating larvae can contribute to pathology. Toxocara larvae can invade the brains of humans, and while case descriptions of cerebral toxocariasis are historically rare, improved diagnosis and greater awareness have contributed to increased detection. Despite this, cerebral or neurological toxocariasis (NT) remains a poorly understood phenomenon. Furthermore, our understanding of cognitive deficits due to toxocariasis in human populations remains particularly deficient. Recent data describe an enhanced expression of biomarkers associated with brain injury, such as GFAP, AβPP, transforming growth factor β1 (TGF-β1), NF-L, S100B, tTG, and p-tau, in mice receiving even low doses of Toxocara ova. Finally, this review outlines a hypothesis to explore the relationship between the presence of T. canis larvae in the brain and the progression of Alzheimer's disease (AD) due to enhanced AD-associated neurodegenerative biomarker expression.

Toxocariasis might be an important cause of atopic myelitis in Korea

Atopic myelitis is defined as myelitis with atopic diasthesis but the cause is still unknown. Toxocariasis is one of the common causes of hyperIgEaemia that may lead to neurologic manifestations. The purpose of this study was to evaluate the sero-prevalence of Toxocara specific IgG Ab among the atopic myelitis patients. We evaluated the medical records of 37 patients with atopic myelitis whose conditions were diagnosed between March 2001 and August 2007. Among them, the 33 sera were analyzed for specific serum IgG Ab to Toxocara excretory-secretory antigens (TES). All of 37 patients had hyperIgEaemia. Specific IgE to D. pteronyssinus and D. farinae was detected in 22 (64.7%) and 34 (100%) patients, respectively, of the 34 patients. Thirty-one of 33 patients (93.9%) were found to be positive by TES IgG enzyme-linked immunosorbent assay (ELISA). Based on the image findings of eosinophilic infiltrations in the lung and liver, 8 patients had positive results. These results inferred that the prevalence of toxocariasis was high in patients with atopic myelitis. Our results suggest that toxocariasis might be an important cause of atopic myelitis and Toxocara ELISA is essential for evaluating the causes of atopic myelitis.

MRI findings of spinal visceral larva migrans of Toxocara canis

PURPOSE

The purpose of this study is to investigate the MRI findings of visceral larva migrans (VLS) of Toxocara canis in spinal cord.

MATERIALS AND METHODS

We retrospectively reviewed spinal MRI findings in eight patients with serologically proven Toxocara canis between 2005 and 2008. We evaluated the location, length, extent and migration of the lesion, MR signal intensity (SI), enhancement pattern, and swelling of the spinal cord. We evaluated clinical features including presenting symptoms and signs and treatment response.

RESULTS

Total 8 patients (M=8; age range 36-79 years) were included. The lesions were located in the cervical or thoracic spinal cord in all patients. All lesions showed high SI and minimal or mild swelling of involved spinal cord on T2WI and focal nodular enhancement on posterior or posterolateral segment of spinal cord. The length of involved lesion was relatively short in most patients. There was a migration of lesion in one patient. In spite of albendazole or steroid treatment, neurological symptoms or signs were not significantly improved in all patients.

CONCLUSION

Although all lesions show non-specific imaging findings like non-tumorous myelopathy mimicking transverse myelitis, single lesion, focal nodular enhancement on posterior or posterolateral segment of spinal cord, relatively short segmental involvement and migration of lesion may be characteristic findings of spinal VLM of Toxocara canis. In addition, the reluctant response to the treatment may be characteristic of spinal VLM of Toxocara canis.

Toxocariasis mimicking liver, lung, and spinal cord metastases from retinoblastoma

A boy with bilateral retinoblastoma underwent metastatic surveillance for increased risk of systemic and central nervous system metastasis because of the extensive choroid and optic nerve invasion in his enucleated eye. Two years after finishing chemotherapy, surveillance MRI showed multiple new liver, lung and spinal cord lesions. High Toxocara antibody titers, eosinophilia, and elevated IgE levels supported a diagnosis of toxocariasis, rather than retinoblastoma metastasis. This is the first report of early, asymptomatic spinal cord toxocariasis diagnosed incidentally through metastatic surveillance.

Neurotoxocarosis

Infection of humans with embryonated eggs of Toxocara canis (larva migrans) remains asymptomatic, or results in covert or common toxocarosis, visceral larva migrans syndrome, or ophthalmologic and neurologic impairment. Though neurological manifestations of Toxocara canis larvae are rare, toxocarosis remains an important differential diagnosis of various neurological disorders. Manifestations of the central nervous system are dementia, meningo-encephalitis, myelitis, cerebral vasculitis, epilepsy, or optic neuritis. Manifestations of the peripheral nervous system comprise radiculitis, affection of cranial nerves, or musculo-skeletal involvement. If toxocarosis is neglected, ignored, or refused as a differential of these abnormalities, it may be easily overlooked for years. Early recognition and treatment of the infection is, however, of paramount importance since it reduces morbidity and mortality and the risk of secondary superinfection. Like the visceral manifestations, neurological manifestations of toxocarosis are treated by benzimidazole components, most frequently albendazole, corticosteroids, or diethylcarbamazine. If detected and treated early, the prognosis of neurological manifestations of toxocarosis is favourable.

Eosinophilic meningomyelitis in toxocariasis: case report and review of the literature

Toxocariasis is a worldwide-occurring parasitic infection leading to tissue damage in various organs due to wandering Toxocara larvae (visceral larva migrans). More than 40 cases of CNS involvement in children and immunocompetent adults have been documented in detail to date. Here, we present evidence of eosinophilic meningomyelitis in an adult without known risk factors and with positive Toxocara antibody response in CSF, but not in blood. Toxocariasis has to remain among the differential diagnosis in patients with eosinophilic CNS infection even if serological tests in blood are negative. Adult cases seem to be more frequent than previously thought (about 60%).

Cerebral toxocariasis: a possible cause of epileptic seizure in children

INTRODUCTION

Toxocariasis is a worldwide human helminthiasis, which is mostly asymptomatic and caused by toxocara canis, a roundworm in dogs. These can cause visceral larva migrans syndrome in humans who ingest contaminated soil. CNS manifestation with a focal mass lesion is very rare, seizures often being the first symptom.

CASE REPORT

We describe an 11-year-old girl presenting with a generalized epileptic seizure and eosinophilia in blood. Under antibiotic therapy under the assumption of toxoplasmosis the lesion did not decrease and surgical resection was considered. We used computer-assisted surgery (CAS) for careful tissue resection. Postoperatively the diagnosis of toxocariasis was confirmed and albendozole medication was administered for 7 days. The patient developed well without neurological deficits or seizures.

CONCLUSION

We conclude that although neurological involvement is rare in toxocariasis, a cerebral infection in a child with epileptic seizures and eosinophilia should be considered.

Toxocariasis of the central nervous system: with report of two cases

Clinical involvement of the nervous system in visceral larva migrans due to Toxocara is rare, although in experimental animals the larvae frequently migrate to the brain. A review of the literature from the early 50's to date found 29 cases of brain involvement in toxocariasis. In 20 cases, various clinical and laboratory manifestations of eosinophilic meningitis, encephalitis, myelitis or radiculopathy were reported. We report two children with neurological manifestations, in which there was cerebrospinal fluid pleocytosis with marked eosinophilia and a positive serology for Toxocara both in serum and CSF. Serology for Schistosoma mansoni, Cysticercus cellulosae, Toxoplasma and cytomegalovirus were negative in CSF, that was sterile in both cases. Improvement of signs and symptoms after specific treatment (albendazole or thiabendazole) was observed in the two cases. A summary of data described in the 25 cases previously reported is presented and we conclude that in cases of encephalitis and myelitis with cerebrospinal fluid pleocytosis and eosinophilia, parasitic infection of the central nervous system should be suspected and serology should be performed to establish the correct diagnosis and treatment.

Eosinophilic meningitis

Eosinophilic meningitis is a rare clinical entity that can be useful in narrowing the differential diagnosis of central nervous system disease. It is defined by the presence of 10 or more eosinophils/microL in the cerebrospinal fluid (CSF) or a CSF eosinophilia of at least 10%. The most common cause is invasion of the central nervous system by helminthic parasites, particularly Angiostrongylus cantonensis, but other infections as well as noninfectious conditions may also be associated. This review describes the etiologies of eosinophilic meningitis, focusing primarily on the helminths that cause CSF eosinophilia.

Eosinophilic pleocytosis and myelitis related to Toxocara canis infection

Toxocara canis causes the visceral larva migrans syndrome in which central nervous involvement is rare. We report the case of a 40-year-old woman presenting with a subacute weakness of the right leg and dysaesthesiae in the right Th8-Th10 dermatomas. Spinal magnetic resonance imaging examination showed abnormal hyperintensity within the spinal cord. Cerebrospinal fluid analysis revealed eosinophilic pleocytosis. Antibody titres to Toxocara canis were higher in the cerebrospinal fluid than in the serum. Treatment using mebendazole led to a complete clinical recovery, normalization of cerebrospinal fluid parameters and improvement in spinal magnetic resonance imaging abnormalities.