Reversible acute methotrexate leukoencephalopathy: atypical brain MR imaging features

Progressive Lower Extremity Paralysis Caused by Intrathecal MTX-Induced Myelopathy Mimicking Guillain-Barre Syndrome: A Case Report

Methotrexate (MTX) is commonly used in intrathecal chemotherapy for patients with acute lymphocytic leukemia (ALL) to prevent central nervous system (CNS) involvement. However, the use of MTX-based chemotherapy can lead to rare yet severe complications, such as MTX-induced myelopathy. Here, we report the case of MTX-induced myelopathy initially misdiagnosed as Guillain-Barre syndrome, leading to a delay in diagnosis and treatment. We present a case of a 39-year-old male with a history of B-cell acute lymphoblastic leukemia (B-ALL) who experienced bilateral foot paresthesia and progressive lower extremity weakness after intrathecal methotrexate (MTX) treatment. Initially, the patient was suspected as having Guillain-Barre syndrome (GBS) due to similar clinical features and nerve conduction studies. The patient received intravenous immunoglobulin (IVIG) treatment, but his condition worsened. T2-weighted images of the thoracic spinal cord revealed high signal intensity in both lateral and posterior columns, typically associated with subacute combined degeneration. However, elevated vitamin B12 levels ruled out SCD in this case. Based on the aforementioned findings, intrathecal methotrexate-induced myelopathy was diagnosed. This case highlights the diagnostic challenge posed by the similarity in clinical presentation between MTX-induced myelopathy and GBS. Differentiating between these conditions is critical for appropriate management. Prompt recognition and treatment with folate metabolism compounds may mitigate neurological sequelae.

Prevalence of leukoencephalopathy and its potential cognitive sequelae in cancer patients

Due to the rising use of chemotherapy treatment in cancer patients and growing survival rates, therapy-induced neurotoxic side effects are increasingly reported. Given the ambiguity about the prevalence and severity of leukoencephalopathy, one of such toxic side effects, in non-central nervous system (CNS) cancer patients, we performed a systematic literature search using the PubMed/Medline database to summarize existing literature regarding leukoencephalopathy epidemiology in non-CNS cancer patients and its potential cognitive sequelae. The search was based on the following terms: ('MRI' OR 'T2-weighted MRI' OR 'FLAIR') AND ('cancer' OR 'tumour' OR 'leukaemia' OR 'neoplasms') AND ('chemotherapy' OR 'radiotherapy') AND ('posterior reversible encephalopathy' OR 'leukoencephalopathy' OR 'cerebral ischaemia' OR 'stroke'). Thirty-two studies discussing the occurrence of leukoencephalopathy in cancer patients were included, of which the majority investigated Acute Lymphoblastic Leukaemia (ALL) patients (n = 22).Regularly scanned ALL patients showed a prevalence of leukoencephalopathy between 17 - 87%, and 15 - 83% of patients presented with leukoencephalopathy when only scanned after a CNS event. When diagnosed with posterior reversible encephalopathy syndrome, 100% of patients showed leukoencephalopathy because its diagnosis is based in part on observable lesions. An increased prevalence was observed in ALL patients treated with higher doses of methotrexate (5 g/m² MTX, 42 - 87%) when compared to lower doses (< 5 g/m², 32 - 67%). By contrast, in breast cancer patients, white matter lesions were mainly detected in case of neurological symptoms, but not (yet) clearly associated with chemotherapy administration. However, chemotherapy treatment was associated with more infratentorial microbleeds in breast cancer patients . Up to 50% of other (neurologically asymptomatic) solid tumour patients presented white matter lesions, even years after treatment. When cognitive data were investigated, lesioned patients showed lower scores on neurocognitive tests in 50% of studies, years after ending therapy.In conclusion, leukoencephalopathy is well-documented for ALL patients (with a focus on methotrexate), but there is a lack of knowledge for other intravenous chemotherapeutics, other oncological populations, wider age ranges and possible risk factors (e.g. history of CNS event). Furthermore, the long-term neuropsychological impact and potential risk for neurodegenerative processes due to leukoencephalopathy remains inconclusive. Hence, large international databanks, epidemiological and prospective case-control studies are necessary to stratify risk groups for CNS-related side effects.

MR imaging findings in some rare neurological complications of paediatric cancer

Abstract

Neurological complications of paediatric cancers are a substantial problem. Complications can be primary from central nervous system (CNS) spread or secondary from indirect or remote effects of cancer, as well as cancer treatments such as chemotherapy and radiation therapy. In this review, we present the clinical and imaging findings of rare but important neurological complications in paediatric patients with cancer. Neurological complications are classified into three phases: pre-treatment, treatment and post-remission. Paraneoplastic neurological syndromes, hyperviscosity syndrome, haemophagocytic lymphohistiocytosis and infection are found in the pre-treatment phase, while Trousseau’s syndrome, posterior reversible encephalopathy syndrome and methotrexate neurotoxicity are found in the treatment phase; though some complications overlap between the pre-treatment and treatment phases. Hippocampal sclerosis, radiation induced tumour, radiation induced focal haemosiderin deposition and radiation-induced white matter injury are found in the post-remission phase. With increasingly long survival after treatment, CNS complications have become more common. It is critical for radiologists to recognise neurological complications related to paediatric cancer or treatment. Magnetic resonance imaging (MRI) plays a significant role in the recognition and proper management of the neurological complications of paediatric cancer.

Teaching Points

• Neurological complications of paediatric cancer include various entities.

• Neurological complications are classified into three phases: pre-treatment, treatment and post-remission.

• Radiologists should be familiar with clinical and imaging findings of neurological complications.

• MRI features may be characteristic and lead to early diagnosis and proper treatments.

Methotrexate-induced leukoencephalopathy presenting as stroke in the emergency department

Methotrexate-induced leukoencephalopathy is to be considered as a potential etiology in any patient presenting with stroke-like symptoms after receiving methotrexate. One of our cases suggests that the method of administration of the methotrexate can be IV or intrathecal and still results in leukoencephalopathy.

A novel mechanism of toxic injury to the Papez circuit from chemotherapy

Toxic effects of chemotherapy delivered via Ommaya reservoir include pericatheter necrosis and toxic leukoencephalopathy. Imaging evidence of toxicity is often asymptomatic, but can be clinically consequential. A young patient, treated for cerebrospinal fluid relapse of acute lymphoblastic leukemia with methotrexate and cytarabine via Ommaya reservoir, presented with acute deterioration of short-term memory. MRI demonstrated extra-ventricular Ommaya catheter position and typical methotrexate-induced changes in the deep white matter, but also signal alteration in the forniceal columns and mammillary bodies, components of the Papez circuit. This case presents a novel mechanism of chemotherapy-induced neurotoxicity associated with extra-ventricular Ommaya catheter position. Specifically, the clinical and imaging findings suggest that extra-ventricular Ommaya catheter position may lead to a direct methotrexate-induced toxicity to the Papez circuit. This provides further clinical evidence of the function of the circuit. The possibility that this patient received a supratherapeutic dose of methotrexate may explain why this presentation with profound memory impairment is not more common. However, this case also provides a potential explanation for patients who receive standard dose chemotherapy via extra-ventricular Ommaya catheter and develop milder memory loss.

Toxic leukoencephalopathies, including drug, medication, environmental, and radiation-induced encephalopathic syndromes

Toxic leukoencephalopathies can be secondary to the exposure to a wide variety of exogenous agents, including cranial irradiation, chemotherapy, antiepileptic agents, drugs of abuse, and environmental toxins. There is no typical clinical picture, and patients can present with a wide array of signs and symptoms. Involvement of white matter is a key finding in this scenario, although in some circumstances other high metabolic areas of the central nervous system can also be affected. Magnetic resonance (MR) imaging usually discloses bilateral and symmetric white matter areas of hyperintense signal on T2-weighted and fluid-attenuated inversion recovery images, and signs of restricted diffusion are associated in the acute stage. In most cases, the changes are reversible, especially with prompt recognition of the disease and discontinuation of the noxious agent. Either the MR or clinical features may be similar to several nontoxic entities, such as demyelinating diseases, leukodystrophies, hepatic encephalopathy, vascular disease, hypoxic-ischemic states, and others. A high index of suspicion should be maintained whenever a patient presents recent onset of neurologic deficit, searching the risk of exposure to a neurotoxic agent. Getting to know the most frequent MR appearances and mechanisms of action of causative agents may help to make an early diagnosis and begin therapy, improving outcome. In this review, some of the most important causes of leukoencephalopathies are presented; as well as other 2 related conditions: strokelike migraine attacks after radiation therapy syndrome and reversible splenial lesions.

Ptosis during hematologic malignancy in children

Neurological symptoms such as ptosis may develop due to either chemotherapeutic agents or involvement of the central nervous system (CNS) during hematologic malignancy. It is difficult to make this distinction according to clinical symptoms and magnetic resonance imaging findings. If the neurologic symptoms are increased, it is a warning of CNS involvement. Herein are described the clinical and neuroimaging features of three patients with hematologic malignancy who presented with ptosis.

Diagnosis of multiple sclerosis

This chapter will serve as a guide for the diagnosis of multiple sclerosis (MS). Primary aims include a review of both the common and atypical clinical manifestations of MS, a detailed discussion of the alternative diagnoses which can mimic MS, as well as a review of the current established diagnostic criteria and a history of their development. It will also review the distinct disease courses and MS variants. The goal of the chapter is to facilitate the diagnostic process for clinicians so that they may expedite early diagnosis and treatment in an effort to alter disease outcomes and ultimately improve patients' quality of life.

Temporal lobe epilepsy with hippocampal sclerosis in acute lymphoblastic leukemia

Of 71 acute lymphoblastic leukemia survivors at our hospital over the past 10 years, 2 children developed mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). This is the first report to describe the clinical course of MTLE-HS observed longitudinally by EEG and MRI. Patient 1 experienced a seizure during chemotherapy involving intrathecal methotrexate. Postseizure MRI suggested methotrexate encephalopathy or leukemic invasion. Anticonvulsant therapy was initiated; subsequent EEGs and MRIs revealed normal results. Three years after chemotherapy, a diffuse, irregular spike-and-wave pattern was observed on interictal EEG. Five years after chemotherapy, the patient developed MTLE-HS comprising complex partial seizures, typical temporal spikes on EEG, and hippocampal sclerosis (HS). Patient 2 did not experience seizures during chemotherapy. Four years later, the patient started experiencing complex partial seizures, and a diffuse, irregular spike-and-wave pattern was observed on interictal EEG. A clinical picture of MTLE-HS developed 2 years later. In both patients, nonspecific EEG abnormalities (ie, diffuse, irregular spike-and-wave activity) preceded the appearance of HS on MRI by 2 years, suggesting an insidious advance of HS during the latent period. Such atypical EEG findings may indicate MTLE-HS during follow-up of leukemia patients. MTLE-HS develops several years after an initial precipitating incident such as prolonged seizures, central nervous system infection, and brain trauma. In our cases, the initial precipitating incident may have been chemotherapy and/or prolonged seizures. Thus, MTLE-HS associated with leukemia may not be as rare as generally believed. A large cohort study of late neurologic complications is warranted.

Cancer pharmacogenomics in children: research initiatives and progress to date

Over the last few decades, cure rates for pediatric cancer have increased dramatically, and now over 80 % of children with cancer are cured of their disease. This improvement in cure has come with a significant cost, with many children suffering irreversible, life-threatening, or long-lasting toxicities due to the medications required during their treatment. In the last 2 decades, major technological advances in genomics and the mapping of the human genome have made it possible to identify genetic differences between children in order to investigate differing responses to cancer therapy and to help explain why children treated with the same medications can have different outcomes. The emerging field of pharmacogenomics has had many important findings in pediatric cancer. The focus of this review is drug toxicity in pediatric cancer and the use of pharmacogenomics to reduce these adverse drug reactions, with a specific focus on thiopurines, methotrexate, cisplatin, vincristine and anthracyclines. Future areas of research and the need for international collaboration are discussed.

Pseudoprogression after high-dose busulfan-thiotepa with autologous stem cell transplantation and radiation therapy in children with brain tumors: Impact on survival

Children with a brain tumor treated with high-dose busulfan-thiotepa with autologous stem cell transplantation (ASCT) and radiation therapy (RT) often experience radiographic changes during follow-up. The purpose of the study was to identify the incidence, time course, risk factors, and clinical outcome of this complication. From May 1988 through May 2007, 110 patients (median age, 3.6 years; range, 1 month to 15.3 years) with a brain tumor had received 1 course of high-dose busulfan-thiotepa with stem cell rescue, followed or preceded by RT as part of their treatment. All MRI follow-up examinations were systematically reviewed. Twenty-three patients (21%) developed neuroradiological abnormalities at a median time of 9.2 months (range, 5.6-17.3 months) after ASCT. All contrast-enhancing lesions appeared in patients who had received RT after ASCT and were localized inside the 50-55Gy isodoses. They disappeared in 14 of 23 patients after a median time of 8 months (range, 3-17 months), leaving microcalcifications in some cases. The presence of MRI abnormalities was an independent prognostic factor for overall survival in the multivariate analysis (hazard ratio, 0.12; 95% confidence interval [CI], 0.04-0.33), with a 5-year overall survival rate of 84% among patients with MRI abnormalities (95% CI, 62-94), compared with 27% (95% CI, 19-37) among those without lesions. MRI-detectable pseudoprogression is a common early finding in children treated with high-dose busulfan-thiotepa followed by radiation therapy and is correlated with a better outcome.

Methotrexate-induced posterior reversible encephalopathy syndrome

WHAT IS KNOWN AND OBJECTIVE

Posterior reversible encephalopathy syndrome (PRES) is described clinically as an acute neurologic deterioration characterized by headache, change in mental status and seizures. Although the mechanism(s) for this syndrome is not fully understood, PRES results from vasogenic edema in areas of the brain supplied by the posterior circulation. Methotrexate (MTX)-induced neurotoxicity is a well-known complication of therapy in the paediatric population but is uncommon in adults.

DETAILS OF THE CASE

We describe a 55-year-old woman with an acute presentation of PRES caused by intrathecal MTX given as part of a treatment regimen for diffuse large B-cell type lymphoma. Both clinical symptoms and radiographic abnormalities resolved 5 days after cessation of treatment.

WHAT IS NEW AND CONCLUSION

We describe what we believe to be the first report of intrathecal MTX-induced PRES in an adult. Clinicians should include MTX-induced PRES in the differential diagnosis of acute neurologic changes in patients receiving this medication. The incidence of MTX-induced neurotoxicity may be under recognized in adults.

[Hemiparesis in acute lymphoblastic leukemia]

The case of an adolescent female patient with acute lymphoblastic leukemia and stroke-like hemiparesis demonstrates a typical manifestation of methotrexate-induced acute encephalopathy. This rare entity occurs both in children and adults and can result from intrathecal as well as high dose intravenous administration of methotrexate. Diagnosis can confidently be made using cerebral MRI including diffusion-weighted imaging (DWI), so that patients can be informed about the favorable prognosis.

Gliomatosis cerebri mimicking chemotherapy-induced leukoencephalopathy in a patient with non-Hodgkin's lymphoma

Patients with hematological malignancies may develop white matter lesions, which are usually associated with chemotherapy. Magnetic resonance imaging (MRI) is the imaging modality of choice for identifying chemotherapy-induced, or "toxic", leukoencephalopathy. Brain biopsy in patients with hematological malignancies suspected of sustaining toxic leukoencephalopathy has rarely been performed, because its characteristic MRI findings are considered pathognomotic. Biopsy may be indicated in atypical cases, however, and it may yield unexpected results. We describe a case with white matter lesions that developed in an elderly man treated for non-Hodgkin's lymphoma. The lesions, initially diagnosed with toxic leukoencephalopathy based on MRI findings, turned out to be gliomatosis cerebri.

Posterior reversible encephalopathy syndrome associated with methotrexate neurotoxicity: conventional magnetic resonance and diffusion-weighted imaging findings

The addition of intrathecal methotrexate to treatment protocols has increased survival rates in children with acute lymphoblastic leukemia but is also associated with varying degrees of neurotoxicity. We describe a 15-year-old female patient diagnosed with acute lymphoblastic leukemia presenting with status epilepticus after receiving intrathecal methotrexate. Magnetic resonance imaging showed reversible cortical and subcortical changes consisting of high-intensity lesions on T2-weighted and fluid-attenuated inversion recovery sequences with postgadolinium enhancement, low signal intensity on diffusion-weighted imaging and increased apparent diffusion coefficient. These findings were consistent with the posterior reversible encephalopathy syndrome. We report our conventional magnetic resonance and diffusion-weighted imaging findings and briefly discuss the pathophysiology of the syndrome.

Treatment of neuro-Behçet's disease: an update

Neurological manifestations of Behçet's disease (neuro-Behçet's disease) present in 5-30% of cases. They are classified into parenchymal and nonparenchymal categories. Poor prognostic factors include multifocal involvement, spinal presentations, more than two attacks per year, progressive course and increased cerebrospinal fluid cell count and protein content at the time of neurologic manifestations. For patients with parenchymal neuro-Behçet's disease without any poor prognostic factor, azathioprine or methotrexate and corticosteroids are recommended as the first-line treatment. For high-risk patients, intravenous cyclophosphamide and corticosteroids are recommended. If these regimens failed, TNF-alpha-blocking drugs, such as infliximab or etanercept, should be added. Alternating IFN-alpha and then chlorambucil or experimental treatments are the last resorts for most refractory patients. Treatment of venous sinus thrombosis is achieved by using anticoagulation and short-term corticosteroids with or without immunosuppressants.

Mesial temporal sclerosis associated with methotrexate-induced leukoencephalopathy

Mesial temporal sclerosis is a common form of symptomatic, localization-related epilepsy in children and adolescents, but its occurrence with acute lymphoblastic leukemia is rare. We present clinical records and neuroimaging results of a 13-year-old patient with acute lymphoblastic leukemia who developed recurrent partial seizures after an episode of leukoencephalopathy thought to be caused by methotrexate. Neuroradiologic images revealed hippocampal abnormalities consistent with the findings of mesial temporal sclerosis. Mesial temporal sclerosis was not previously reported in acute lymphoblastic leukemia patients with methotrexate-induced leukoencephalopathy. However, our case suggests that the pathogenesis of mesial temporal sclerosis may be associated with methotrexate-induced neurotoxicity.

Neurocognitive late effects of chemotherapy in children: the past 10 years of research on brain structure and function

Advances in the treatment of childhood cancers have greatly improved survivorship. Success has not come without cost, however, as survivors are at risk for late effects of treatment, including neurocognitive late effects (e.g., difficulties with thinking and reasoning). In the advent of chemotherapy-only protocols, researchers are examining neurocognitive sequelae of these agents to understand the specific role of chemotherapy in neurocognitive changes and the mechanism through which these occur. In this review, we examine the state of the literature on neurocognitive late effects after chemotherapy and their proposed neural mechanisms.

Quantitative morphologic evaluation of magnetic resonance imaging during and after treatment of childhood leukemia

INTRODUCTION

Medical advances over the last several decades, including CNS prophylaxis, have greatly increased survival in children with leukemia. As survival rates have increased, clinicians and scientists have been afforded the opportunity to further develop treatments to improve the quality of life of survivors by minimizing the long-term adverse effects. When evaluating the effect of antileukemia therapy on the developing brain, magnetic resonance (MR) imaging has been the preferred modality because it quantifies morphologic changes objectively and noninvasively.

METHOD AND RESULTS

Computer-aided detection of changes on neuroimages enables us to objectively differentiate leukoencephalopathy from normal maturation of the developing brain. Quantitative tissue segmentation algorithms and relaxometry measures have been used to determine the prevalence, extent, and intensity of white matter changes that occur during therapy. More recently, diffusion tensor imaging has been used to quantify microstructural changes in the integrity of the white matter fiber tracts. MR perfusion imaging can be used to noninvasively monitor vascular changes during therapy. Changes in quantitative MR measures have been associated, to some degree, with changes in neurocognitive function during and after treatment.

CONCLUSION

In this review, we present recent advances in quantitative evaluation of MR imaging and discuss how these methods hold the promise to further elucidate the pathophysiologic effects of treatment for childhood leukemia.

Diffusion and perfusion imaging in subacute neurotoxicity following high-dose intravenous methotrexate

Methotrexate (MTX) is a widely used chemotherapeutic agent that can cause acute, subacute, and chronic neurological complications. Subacute MTX neurotoxicity is manifest by abrupt onset of focal cerebral dysfunction occurring days to weeks after MTX administration, usually in children. We describe the neuroimaging features of an adult patient with primary CNS lymphoma who presented with transient aphasia and right hemiparesis 12 days after receiving intravenous high-dose MTX (8 g/m2) chemotherapy. Imaging within 1 h of symptom onset showed bilateral symmetrical restricted diffusion involving white matter of the cerebral hemispheres. CT angiogram and dynamic susceptibility MRI showed no evidence of vasospasm or perfusion defect. MRI five days later showed near-complete resolution of the abnormalities. MRI 3(1/2) months later showed normal diffusion but new hyperintense T2-weighted signal changes in the subcortical white matter corresponding to previous areas of restricted diffusion. The absence of vascular or perfusion abnormalities suggests that transient cytotoxic edema in white matter may explain the syndrome of subacute MTX neurotoxicity.