Autoimmune-mediated encephalitis and mimics: A neuroimaging review

Intersection between lung cancer and neuroscience: Opportunities and challenges

Lung cancer, which has the highest morbidity and mortality rates worldwide, involves intricate interactions with the nervous system. Research indicates that the nervous system not only plays a role in the origin of lung cancer, but also engages in complex interactions with cancer cells through neurons, neurotransmitters, and various neuroactive molecules during tumor proliferation, invasion, and metastasis, especially in brain metastases. Cancer and its therapies can remodel the nervous system. Despite advancements in immunotherapy and targeted therapies in recent years, drug resistance of lung cancer cells after treatment limits improvements in patient survival and prognosis. The emergence of neuroscience has created new opportunities for the treatment of lung cancer. However, it also presents challenges. This review emphasizes that a deeper understanding of the interactions between the nervous system and lung cancer, along with the identification of new therapeutic targets, may lead to significant advancements or even a revolution in treatment strategies for patients with lung cancer.

MRI in Diagnosis of Autoimmune Encephalitis

MRI has an important role in the diagnosis of autoimmune encephalitis (AE), including enabling identification of abnormalities in the limbic structures, striatum, diencephalon, and romboencephalon and distinguishing entities that mimic AE.

MELAS Presenting as Bilateral Symmetric Occipital and Temporal Cortices Lesions: A Case Report and Literature Review

INTRODUCTION

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode (MELAS) is one of the most common maternally inherited mitochondrial diseases. The stroke-like episode affecting the cortical cortex is the hallmark of MELAS; however, it rarely presents as simultaneously bilateral symmetric cortices lesions.

CASE REPORT

We reported a case of MELAS in a 46-year-old female patient with bilateral symmetric occipital and internal temporal cortices involvements on brain magnetic resonance imaging (MRI). A literature review of MELAS patients and a retrospective analysis were performed. She had a family history of diabetes. Although she denied a history of diabetes, elevated blood glucose was noted after admission, and diabetes was diagnosed. Laboratory examination revealed elevated lactate acid and creatine kinase levels in blood. Cranial computed tomography (CT) image demonstrated basal ganglia calcification, as well as subtle decreased attenuation in bilateral symmetric occipital and internal temporal cortices. Brain magnetic resonance imaging (MRI) demonstrated symmetric gyriform hyperintensity in bilateral occipital lobes and internal temporal lobes in both grey and white matter on fluid-attenuated inversion recovery (FLAIR) images with restricted diffusion on diffusion weighted images (DWI). A genetic test revealed a point mutation in the mtDNA(3243A > G) by blood examination. Literature review showed that there were 231 eligible patients with MELAS identified from 212 published papers. Symmetric cortical involvements were seen in 15 (6.5%) patients on brain MRI.

CONCLUSIONS

MELAS should be considered as a potential diagnosis in the patients with bilateral symmetric stroke-like cortices lesions.

Magnetic Resonance Imaging (MRI) Findings in Pediatric Autoimmune Encephalitis: A Case Report

Autoimmune encephalitis (AE) is a rare condition that involves an immune-mediated attack on the brain, often presenting with seizures, altered consciousness, and other neuropsychiatric symptoms. This case report describes a seven-year-old girl who presented with acute brain dysfunction, including seizures and disturbed consciousness, following a gastrointestinal illness. Magnetic resonance imaging (MRI) findings revealed early signs of AE, including hyperintensities in the external capsules and medial temporal lobe. Following negative infectious workups, the diagnosis of AE was confirmed, and the patient was treated with immunomodulatory therapy, leading to gradual improvement. This case emphasizes the importance of early recognition, the role of MRI in diagnosis, and the need for prompt treatment to improve outcomes in pediatric AE.

Coexistence of Anti-GAD and Anti-GABAAR Antibodies in an Autoimmune Encephalitis Patient: A Case Report

Background

Coexistence of autoimmune encephalitis (AE) with multiple autoantibodies is of particular concern because overlying antibodies may cause variation of clinical manifestations. Coexistence of anti-glutamic acid decarboxylase (GAD) and anti-Gamma-aminobutyric acid-α-receptor (GABAAR) antibodies in AE was rare.

Case Presentation

A 44-year-old female patient presented to our hospital due to cognitive decline for 4 years, seizures, slowed speech and depression for 2 months. Based on her clinical manifestations and laboratory assessment results (positive anti-GAD and anti-GABAAR antibodies), she was diagnosed as AE with coexisting anti-GAD and anti-GABAAR antibodies. After treatment with intravenous methylprednisolone (at dose of 1000mg/d, 500mg/d, 250mg/d, 120mg/d, 80mg/d for 3 days respectively) and intravenous immunoglobulin (400 mg/kg/d for 5 days), her symptoms gradually improved with exception for the slowed speech. Oral prednisone acetate was continued after discharge, her symptoms of slowed speech improved at 6-month follow-up.

Conclusion

We report a case of AE co-existing with anti-GAD and anti-GABAAR antibodies, which has different characteristics from previous cases. Coexistence of neural auto-antibodies should be considered when patients suspected with autoimmune encephalitis.

Case report: An autopsy report of patient with metastatic brain tumor and carcinomatous meningitis mimicking paraneoplastic neurological syndrome

Differential diagnosis of metastatic brain tumor, carcinomatous meningitis, and paraneoplastic neurological syndrome (PNS) can be challenging in atypical cases. When examining patient with increased T2 fluid-attenuated inversion recovery (FLAIR) hyperintensities in the temporal polar white matter, autoimmune encephalitis, including PNS, should be considered. Herein, we report the case of an 85-year-old man with carcinomatous meningitis due to lung large cell carcinoma. He showed disturbance of consciousness, abnormal behavior, incomprehensible speech, and apathy, which suggested brain dysfunction. Magnetic resonance imaging revealed high intensities on the whole cerebellum on a diffusion-weighted image and bilateral T2 FLAIR hyperintensities in the temporal polar white matter. Cerebrospinal fluid analysis and cytology showed elevated total protein levels, pleocytosis, and atypical cells with nuclear enlargement, hyperchromasia, and irregular shape. Autopsy revealed lung large cell carcinoma and its brain metastasis. Tumor cells were disseminated to the central nervous system along the subarachnoid space. Furthermore, plenty of carcinoma cells and peritumoral enlarged perivascular space were observed in the temporal poles. To our knowledge, this is the first report of bilateral T2 FLAIR hyperintensities in the temporal polar white matter caused by carcinomatous meningitis with pathological confirmation. In patient with carcinomatous meningitis, abnormal T2 FLAIR hyperintensities may not be derived from ischemia or tumor invasion to parenchyma.

Uncommon and Miscellaneous Inflammatory Disorders of the Brain and Spine

Inflammatory disorders of the brain and spine have a highly variable MRI appearance, often demonstrating significant overlap in imaging features. The resulting diagnostic dilemma is particularly challenging when considering the more uncommon neuroinflammatory entities. Diligent examination of the salient clinical presentation and signal alteration on imaging examination is necessary when considering neuroinflammation as a diagnostic possibility and may aid in raising suspicion for a particular neuroinflammatory entity. This article reviews a selection of uncommon and miscellaneous inflammatory disorders of the brain and spine to raise awareness of the clinical and imaging features that may assist in this challenging diagnostic task.

Herpes simplex encephalitis initially presenting without fever or cerebrospinal fluid pleocytosis and with typical neuroimaging findings: a case report

Herpes simplex encephalitis (HSE) is a common viral encephalitis that can be fatal if not adequately treated. Fever, cerebrospinal fluid (CSF) pleocytosis, and typical neuroimaging findings are commonly observed in HSE cases. We encountered a patient with HSE who did not exhibit these classic clinical features. A 63-year-old male presented with his first-ever seizure. Fever did not develop until the fourth day of admission, and neither neuroimaging nor CSF analysis revealed abnormalities. Under suspicion of autoimmune encephalitis, methylprednisolone was administered. Subsequently, when the patient developed fever, a follow-up neuroimaging study was performed and revealed abnormalities consistent with HSE. The patient was promptly treated with acyclovir, which led to a full recovery. Diagnosing HSE in patients who present without fever or CSF pleocytosis and with typical neuroimaging findings poses a challenge. Therefore, prior to initiating immunosuppressive treatment, it is crucial to closely observe patients and to conduct follow-up tests, including neuroimaging and CSF analysis.

Case Report: Brain tumor's pitfalls: two cases of high-grade brain tumors mimicking autoimmune encephalitis with positive onconeuronal antibodies

Background

Glioblastoma (GBM) is the most common primary brain tumor in adulthood. Initial diagnosis is generally based on clinical and MRI findings, which may be misinterpreted as other neurological pictures, including autoimmune encephalitis (AE). AE is a heterogeneous group of neuroinflammatory diseases due to the presence of auto-antibodies targeting antigens on neuronal synaptic or cell surface. In the present report, we describe two peculiar cases of GBM initially misdiagnosed as AE, focusing on the diagnostic pitfalls and the treatment strategies.

Methods

We report the case of two patients with high-grade brain tumors, initially misdiagnosed and treated for AE. Clinical, laboratory, and neuroradiological data are discussed in terms of differential diagnosis between AE and GBM.

Results

The presence of atypical brain MRI findings and the unresponsiveness to immunosuppressive treatment are major red flags in the differential diagnosis between AE and GBM. In these cases, a brain biopsy is necessary to confirm the diagnosis.

Conclusions

Atypical brain tumor presentation causes a diagnostic and therapeutic delay. A positive onconeural autoantibodies result should always be interpreted cautiously, considering the possibility of a false-positive test. A brain biopsy is mandatory for a definite diagnosis.

Biomarkers in autoimmune diseases of the central nervous system

The autoimmune diseases of the central nervous system (CNS) represent individual heterogeneity with different disease entities. Although clinical and imaging features make it possible to characterize larger patient cohorts, they may not provide sufficient evidence to detect disease activity and response to disease modifying drugs. Biomarkers are becoming a powerful tool due to their objectivity and easy access. Biomarkers may indicate various aspects of biological processes in healthy and/or pathological states, or as a response to drug therapy. According to the clinical features described, biomarkers are usually classified into predictive, diagnostic, monitoring and safety biomarkers. Some nerve injury markers, humoral markers, cytokines and immune cells in serum or cerebrospinal fluid have potential roles in disease severity and prognosis in autoimmune diseases occurring in the CNS, which provides a promising approach for clinicians to early intervention and prevention of future disability. Therefore, this review mainly summarizes the potential biomarkers indicated in autoimmune disorders of the CNS.