Striatal hypermetabolism in limbic encephalitis

Quantitative brain 18F-FDG PET/CT analysis in seronegative autoimmune encephalitis

OBJECTIVE

Brain 18F-FDG PET/CT is a useful diagnostic in evaluating patients with suspected autoimmune encephalitis (AE). Specific patterns of brain dysmetabolism have been reported in anti-NMDAR and anti-LGI1 AE, and the degree of dysmetabolism may correlate with clinical functional status.18FDG-PET/CT abnormalities have not yet been described in seronegative AE.

METHODS

We conducted a cross-sectional analysis of brain18FDG-PET/CT data in people with seronegative AE treated at the Johns Hopkins Hospital. Utilizing NeuroQ™ software, the Z-scores of 47 brain regions were calculated relative to healthy controls, then visually and statistically compared for probable and possible AE per clinical consensus diagnostic criteria to previous data from anti-NMDAR and anti-LGI1 cohorts.

RESULTS

Eight probable seronegative AE and nine possible seronegative AE were identified. The group only differed in frequency of abnormal brain MRI, which was seen in all of the probable seronegative AE patients. Both seronegative groups had similar overall patterns of brain dysmetabolism. A common pattern of frontal lobe hypometabolism and medial temporal lobe hypermetabolism was observed in patients with probable and possible seronegative AE, as well as anti-NMDAR and anti-LGI1 AE as part of their respective characteristic patterns of dysmetabolism. Four patients had multiple brain18FDG-PET/CT scans, with changes in number and severity of abnormal brain regions mirroring clinical status.

CONCLUSIONS

A18FDG-PET/CT pattern of frontal lobe hypometabolism and medial temporal lobe hypermetabolism could represent a common potential biomarker of AE, which along with additional clinical data may facilitate earlier diagnosis and treatment.

Dopamine, Immunity, and Disease

The neurotransmitter dopamine is a key factor in central nervous system (CNS) function, regulating many processes including reward, movement, and cognition. Dopamine also regulates critical functions in peripheral organs, such as blood pressure, renal activity, and intestinal motility. Beyond these functions, a growing body of evidence indicates that dopamine is an important immunoregulatory factor. Most types of immune cells express dopamine receptors and other dopaminergic proteins, and many immune cells take up, produce, store, and/or release dopamine, suggesting that dopaminergic immunomodulation is important for immune function. Targeting these pathways could be a promising avenue for the treatment of inflammation and disease, but despite increasing research in this area, data on the specific effects of dopamine on many immune cells and disease processes remain inconsistent and poorly understood. Therefore, this review integrates the current knowledge of the role of dopamine in immune cell function and inflammatory signaling across systems. We also discuss the current understanding of dopaminergic regulation of immune signaling in the CNS and peripheral tissues, highlighting the role of dopaminergic immunomodulation in diseases such as Parkinson's disease, several neuropsychiatric conditions, neurologic human immunodeficiency virus, inflammatory bowel disease, rheumatoid arthritis, and others. Careful consideration is given to the influence of experimental design on results, and we note a number of areas in need of further research. Overall, this review integrates our knowledge of dopaminergic immunology at the cellular, tissue, and disease level and prompts the development of therapeutics and strategies targeted toward ameliorating disease through dopaminergic regulation of immunity. SIGNIFICANCE STATEMENT: Canonically, dopamine is recognized as a neurotransmitter involved in the regulation of movement, cognition, and reward. However, dopamine also acts as an immune modulator in the central nervous system and periphery. This review comprehensively assesses the current knowledge of dopaminergic immunomodulation and the role of dopamine in disease pathogenesis at the cellular and tissue level. This will provide broad access to this information across fields, identify areas in need of further investigation, and drive the development of dopaminergic therapeutic strategies.

Positron emission tomography in autoimmune encephalitis: Clinical implications and future directions

¹⁸ F-fluoro-deoxyglucose position emission tomography (¹⁸ F-FDG-PET) has been proven as a sensitive and reliable tool for diagnosis of autoimmune encephalitis (AE). More attention was paid to this kind of imaging because of the shortage of MRI, EEG, and CSF findings. FDG-PET has been assessed in a few small studies and case reports showing apparent abnormalities in cases where MRI does not. Here, we summarized the patterns (specific or not) in AE with different antibodies detected and the clinical outlook for the wide application of FDG-PET considering some limitations. Specific patterns based on antibody subtypes and clinical symptoms were critical for identifying suspicious AE, the most common of which was the anteroposterior gradient in anti- N -methyl- d -aspartate receptor (NMDAR) encephalitis and the medial temporal lobe hypermetabolism in limbic encephalitis. And the dynamic changes of metabolic presentations in different phases provided us the potential to inspect the evolution of AE and predict the functional outcomes. Except for the visual assessment, quantitative analysis was recently reported in some voxel-based studies of regions of interest, which suggested some clues of the future evaluation of metabolic abnormalities. Large prospective studies need to be conducted controlling the time from symptom onset to examination with the same standard of FDG-PET scanning.

Periodic electroencephalographic discharges and epileptic spasms involve cortico-striatal-thalamic loops on Arterial Spin Labeling Magnetic Resonance Imaging

Periodic discharges are a rare peculiar electroencephalogram pattern, occasionally associated with motor or other clinical manifestations, usually observed in critically ill patients. Their underlying pathophysiology remains poorly understood. Epileptic spasms in clusters and periodic discharges with motor manifestations share similar electroencephalogram pattern and some aetiologies of unfavourable prognosis such as subacute sclerosing panencephalitis or herpes encephalitis. Arterial spin labelling magnetic resonance imaging identifies localizing ictal and inter-ictal changes in neurovascular coupling, therefore assumed able to reveal concerned cerebral structures. Here, we retrospectively analysed ictal and inter-ictal arterial spin labelling magnetic resonance imaging in patients aged 6 months to 15 years (median 3 years 4 months) with periodic discharges including epileptic spasms, and compared these findings with those of patients with drug-resistant focal epilepsy who never presented periodic discharges nor epileptic spasms as well as to those of age-matched healthy controls. Ictal electroencephalogram was recorded either simultaneously with arterial spin labelling magnetic resonance imaging or during the close time lapse of patients' periodic discharges, whereas inter-ictal examinations were performed during the patients' active epilepsy but without seizures during the arterial spin labelling magnetic resonance imaging. Ictal arterial spin labelling magnetic resonance imaging was acquired in five patients with periodic discharges [subacute sclerosing panencephalitis (1), stroke-like events (3), West syndrome with cortical malformation (1), two of them also had inter-ictal arterial spin labelling magnetic resonance imaging]. Inter-ictal group included patients with drug-resistant epileptic spasms of various aetiologies (14) and structural drug-resistant focal epilepsy (8). Cortex, striatum and thalamus were segmented and divided in six functional subregions: prefrontal, motor (rostral, caudal), parietal, occipital and temporal. Rest cerebral blood flow values, absolute and relative to whole brain, were compared with those of age-matched controls for each subregion. Main findings were diffuse striatal as well as cortical motor cerebral blood flow increase during ictal examinations in generalized periodic discharges with motor manifestations (subacute sclerosing panencephalitis) and focal cerebral blood flow increase in corresponding cortical-striatal-thalamic subdivisions in lateralized periodic discharges with or without motor manifestations (stroke-like events and asymmetrical epileptic spasms) with straight topographical correlation with the electroencephalogram focus. For inter-ictal examinations, patients with epileptic spasms disclosed cerebral blood flow changes in corresponding cortical-striatal-thalamic subdivisions (absolute-cerebral blood flow decrease and relative-cerebral blood flow increase), more frequently when compared with the group of drug-resistant focal epilepsies, and not related to Vigabatrin treatment. Our results suggest that corresponding cortical-striatal-thalamic circuits are involved in periodic discharges with and without motor manifestations, including epileptic spasms, opening new insights in their pathophysiology and new therapeutical perspectives. Based on these findings, we propose a model for the generation of periodic discharges and of epileptic spasms combining existing pathophysiological models of cortical-striatal-thalamic network dynamics.

Decrease in the cortex/striatum metabolic ratio on [18F]-FDG PET: a biomarker of autoimmune encephalitis

PURPOSE

The aim of this [¹⁸F]-FDG PET study was to determine the diagnostic value of the cortex/striatum metabolic ratio in a large cohort of patients suffering from autoimmune encephalitis (AE) and to search for correlations with the course of the disease.

METHODS

We retrospectively collected clinical and paraclinical data of patients with AE, including brain ¹⁸F-FDG PET/CT. Whole-brain statistical analysis was performed using SPM8 software after activity parametrization to the striatum in comparison to healthy subjects. The discriminative performance of this metabolic ratio was evaluated in patients with AE using receiver operating characteristic curves against 44 healthy subjects and a control group of 688 patients with MCI. Relationship between cortex/striatum metabolic ratios and clinical/paraclinical data was assessed using univariate and multivariate analysis in patients with AE.

RESULTS

Fifty-six patients with AE were included. In comparison to healthy subjects, voxel-based statistical analysis identified one large cluster (p-cluster < 0.05, FWE corrected) of widespread decreased cortex/striatum ratio in patients with AE. The mean metabolic ratio was significantly lower for AE patients (1.16 ± 0.13) than that for healthy subjects (1.39 ± 0.08; p < 0.001) and than that for MCI patients (1.32 ± 0.11; p < 0.001). A ratio threshold of 1.23 allowed to detect AE patients with a sensitivity of 71% and a specificity of 82% against MCI patients, and 98% against healthy subjects. A lower cortex/striatum metabolic ratio had a trend towards shorter delay before ¹⁸F-FDG PET/CT (p = 0.07) in multivariate analysis.

CONCLUSION

The decrease in the cortex/striatal metabolic ratio has a good early diagnostic performance for the differentiation of AE patients from controls.

Metabolic scoring in autoimmune epilepsy-Should APE scores be modified?

OBJECTIVE

We evaluate the potential utility of F-18 FDG-PET in addition to MRI in the diagnostic work-up of patients with autoimmune epilepsy (AE) and propose the inclusion of functional imaging in the antibody prevalence in epilepsy (APE) scoring system.

METHODS

This was a retrospective analysis in 60 patients, diagnosed and treated for AE, of whom 40 were antibody negative (presumed AE) and 20 were antibody positive (definitive AE). All patients had undergone a dedicated brain and whole body FDG-PET in the department of Nuclear Medicine.

RESULTS

In the antibody negative group, MRI supported a diagnosis of AE in 23 patients. Both MRI and PET were indicative in 12 cases, and standalone PET was positive in 8. While MRI alone was diagnostic in 57% (23/40), the combined yield of both modalities was 77% (31/40). When PET scores were added to assign the APE score in MRI negative cases, average APE score was 5.4. In the antibody positive group, MRI supported the diagnosis of AE in 7 patients. Both MRI and PET were positive in 4 patients and standalone PET was positive in 5 patients. While MRI alone was diagnostic in 35% (7/20), the combined yield of both modalities was 60% (12/20). When PET scores were added to assign the APE score in MRI negative cases, average APE score was 6.1.

CONCLUSION

The inclusion of metabolic information from PET distinctly improved (the sensitivity of) APE scores to predict autoimmune origin even in antibody negative cases. A larger prospective study of similar type could justify adoption of FDG-PET into the standard diagnostic procedure.

Seizures and epilepsy of autoimmune origin: A long-term prospective study

OBJECTIVE

To follow prospectively a group of patients with seizures or epilepsy and suggestive clinical features of autoimmune aetiology and find out how many are finally diagnosed with acute symptomatic seizures (ASS) secondary to autoimmune encephalitis or autoimmune-related epilepsy, and how many develop epilepsy.

METHODS

Consecutive patients meeting the inclusion criteria from 2010 to 2018 were identified. Patients were classified as confirmed, probable autoimmune, non-autoimmune, or unknown.

RESULTS

One-hundred and nine patients were included, 64 (48.7 %) women, mean age 55.2 years (SD 17.9). ASS were reported by 61 patients (56 %), while 48 presented epilepsy (44 %). During follow-up 18 patients died (16.5 %). Final diagnosis was autoimmune-relatedepilepsy (confirmed + probable) in 22 cases and ASS secondary to autoimmune encephalitis (confirmed or probable) in 27, non-autoimmune aetiologies or other diagnosis in 49 (44 %), and unknown aetiology in 11 (10.2 %). Neuronal antibodies (ab) were found in 27 patients (24.7 %). T-lymphocyte infiltration in temporal lobes was observed in 2/8 patients (20 %). Neuronal ab were more frequent in the autoimmune groups: 17 patients (29.8 %) vs 1(2.3 %), p:0.001, and they suffered more autoimmune diseases: 37 (75.5 %) vs 12 (24.48 %), p:0.0001, and 34 (69 %) vs 22 (44.9 %) p:0.027, respectively. All patients with GAD ab 17/17 (100 %) evolved to chronic disease. Four patients (29 %) with ASS secondary to autoimmune encephalitis developed epilepsy.

SIGNIFICANCE

ASS secondary to autoimmune encephalitis or autoimmune-related epilepsy will be diagnosed in nearly half of patients who have been suspected of it. The only diagnostic clue is neuronal ab. Patients who have suffered ASS secondary to autoimmune encephalitis may develop epilepsy over time.

18F-FDG-PET/MRI in the diagnostic work-up of limbic encephalitis

Introduction

Limbic encephalitis (LE) is an immune-related, sometimes paraneoplastic process of the central nervous system. Initial diagnosis and treatment are based on the clinical presentation as well as antibody profiles and MRI. This study investigated the diagnostic value of integrated ¹⁸F-FDG-PET/MRI in the diagnostic work-up of patients with LE for a cerebral and whole-body imaging concept.

Material and methods

Twenty patients with suspected LE were enrolled in this prospective study. All patients underwent a dedicated PET/MRI protocol of the brain as well as the whole-body. Two neuroradiologists, one body radiologist and one nuclear medicine physician performed blinded consensus readings of each corresponding MRI and PET/MRI dataset of the brain and whole-body. Diagnostic confidence was evaluated on a Likert scale.

Results

Based on integrated PET/MRI 19 / 20 patients were found to show morphologic and / or metabolic changes indicative of LE, whereas sole MRI enabled correct identification in 16 / 20 patients. Three patients with negative MRI showed metabolic changes of the limbic system or extra-limbic regions, shifting the diagnosis from (negative) MRI to positive for LE in PET/MRI. Whole-body staging revealed suspected lesions in 2/20 patients, identified by MRI and PET, one confirmed as malignant and one false positive. Diagnostic confidence for cerebral and whole-body imaging reached higher scores for PET/MRI (cerebral: 2.7 and whole body: 4.8) compared to MRI alone (cerebral: 2.4 and whole body: 4.5).

Conclusion

LE diagnosis remains challenging for imaging as it shows only subtle imaging findings in most patients. Nevertheless, based on the simultaneous and combined analysis of morphologic and metabolic data, integrated PET/MRI may enable a dual platform for improved diagnostic confidence and overall detection of LE as well as whole-body imaging for exclusion of paraneoplastic LE.

Diagnosis and Management of Autoimmune Dementia

PURPOSE OF REVIEW

To describe the clinical, laboratory, and MRI features that characterize cognitive decline in the setting of central nervous system (CNS) autoimmunity, and provide an overview of current treatment modalities.

RECENT FINDINGS

The field of autoimmune neurology is rapidly expanding due to the increasing number of newly discovered autoantibodies directed against specific CNS targets. The clinical syndromes associated with these autoantibodies are heterogeneous but frequently share common, recognizable clinical, and MRI characteristics. While the detection of certain autoantibodies strongly suggest the presence of an underlying malignancy (onconeural autoantibodies), a large proportion of cases remain idiopathic. Cognitive decline and encephalopathy are common manifestations of CNS autoimmunity, and can mimic neurodegenerative disorders. Recent findings suggest that the frequency of autoimmune encephalitis in the population is higher than previously thought, and potentially rivals that of infectious encephalitis. Moreover, emerging clinical scenarios that may predispose to CNS autoimmunity are increasingly been recognized. These include autoimmune dementia/encephalitis post-herpes simplex virus encephalitis, post-transplant and in association with immune checkpoint inhibitor treatment of cancer. Early recognition of autoimmune cognitive impairment is important given the potential for reversibility and disability prevention with appropriate treatment. Autoimmune cognitive impairment is treatable and may arise in a number of different clinical settings, with important treatment implications. Several clinical and para-clinical clues may help to differentiate these disorders from dementia of other etiologies.

Autoimmune epilepsy

Seizures are a common manifestation of autoimmune limbic encephalitis and multifocal paraneoplastic disorders. Accumulating evidence supports an autoimmune basis for seizures in the absence of syndromic manifestations of encephalitis. The autoimmune epilepsies are immunologically mediated disorders in which recurrent seizures are a primary and persistent clinical feature. When other etiologies have been excluded, an autoimmune etiology is suggested in a patient with epilepsy upon detection of neural autoantibodies and/or the presence of inflammatory changes on cerebrospinal fluid (CSF) or magnetic resonance imaging. In such patients, immunotherapy may be highly effective, depending on the particular autoimmune epilepsy syndrome present. In this chapter, several autoimmune epilepsy syndromes are discussed. First, epilepsies secondary to other primary autoimmune disorders will be discussed, and then those associated with antibodies that are likely to be pathogenic, such as voltage-gated potassium channel-complex and N-methyl-d-aspartate receptor, gamma-aminobutyric acid A and B receptor antibodies. For each syndrome, the typical clinical, imaging, electroencephaloram, CSF, and serologic features, and pathophysiology and treatment are described. Finally, suggested guidelines for the recognition, evaluation, and treatment of autoimmune epilepsy syndromes are provided.

Semi-quantitative analysis of cerebral FDG-PET reveals striatal hypermetabolism and normal cortical metabolism in a case of VGKCC limbic encephalitis

In the context of delayed autoimmune encephalitis antibody results, functional imaging can support the diagnosis of limbic encephalitis associated with anti-voltage-gated potassium channel complex (VGKCC) antibodies. Here we present a typical case of VGKCC encephalitis in a 69-year-old woman whose symptoms responded to plasmapheresis. A cerebral 18F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) scan performed prior to commencing treatment revealed striatal hypermetabolism assessed qualitatively and semi-quantitatively, with normal uptake in the cortex and cerebellum when analysed semi-quantitatively. Repeat FDG-PET imaging performed three months later revealed normalisation of striatal hypermetabolism. Previous case reports have described striatal hypermetabolism and/or cortical hypometabolism in patients with VGKCC encephalitis. However, most of these descriptions were based on qualitative analyses only and may represent the relative change in cortical metabolism compared with striatal metabolism. We recommend semi-quantitative analysis of cerebral FDG-PET, in addition to reporting the qualitative FDG-PET images.

Voltage-gated potassium channel antibody limbic encephalitis: a case illustrating the neuropsychiatric and PET/CT features with clinical and imaging follow-up

OBJECTIVE

To illustrate the neuropsychiatric and imaging findings in a confirmed case of voltage-gated potassium channel antibody limbic encephalitis.

METHOD

Case report and review of the literature.

RESULTS

A 64-year-old man presented with several months' history of obsessive thoughts and compulsions associated with faciobrachial dystonic seizures. He had no significant past medical and psychiatric history. Physical examinations revealed only mildly increased tone in the left upper limb. Bedside cognitive testing was normal. Positron-emission tomography showed intense symmetrical uptake in the corpus striatum. No underlying malignancy was identified on whole body imaging. Magnetic resonance imaging, lumbar puncture and electroencephalogram were normal. Serum voltage-gated potassium channel antibodies were strongly positive. The patient had a favourable response to antiepileptic drugs, oral steroids and immunotherapy.

CONCLUSIONS

Voltage-gated potassium channel limbic encephalitis characteristically presents with neuropsychiatric symptoms and temporal lobe seizures. Positron-emission tomography-computed tomography can be a useful adjunct to the clinical and biochemical work-up.

Cerebral (18)FluoroDeoxy-Glucose Positron Emission Tomography in paediatric anti N-methyl-D-aspartate receptor encephalitis: A case series

BACKGROUND

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a frequent and severe cause of encephalitis in children with potential efficient treatment (immunotherapy). Suggestive clinical features are behavioural troubles, seizures and movement disorders. Prompt diagnosis and treatment initiation are needed to guarantee favourable outcome. Nevertheless, diagnosis may be challenging because of the classical ancillary test (magnetic resonance imaging (MRI), electroencephalogram, standard cerebro-spinal fluid analysis) have limited sensitivity. Currently, immunological analyses are needed for the diagnostic confirmation. In adult patients, some studies suggested a potential role of cerebral (18)FluoroDeoxy-Glucose Positron Emission Tomography (FDG-PET) in the evaluation of anti-NMDAR encephalitis. Nevertheless, almost no data exist in paediatric population.

METHOD

We report retrospectively clinical, ancillary tests and cerebral FDG-PET data in 6 young patients (median age=10.5 years, 4 girls) with immunologically confirmed anti-NMDAR encephalitis.

RESULTS

Our patients presented classical clinical features of anti-NMDAR encephalitis with severe course (notably four patients had normal MRI). Our series shows the feasibility and the good sensitivity of cerebral FDG-PET (6/6 patients with brain metabolism alteration) in paediatric population. We report some particular features in this population: extensive, symmetric cortical hypometabolism especially in posterior areas; asymmetric anterior focus of hypermetabolism; and basal ganglia hypermetabolism. We found also a good correlation between the clinical severity and the cerebral metabolism changes. Moreover, serial cerebral FDG-PET showed parallel brain metabolism and clinical improvement.

CONCLUSION

Our study reveals the existence of specific patterns of brain metabolism alteration in anti-NMDAR encephalitis in paediatric population.

Autoimmune dementia and encephalopathy

Autoimmune dementia and encephalopathies (ADE) are complex disorders that can cause immune-mediated cognitive deficits and have confusing nomenclature. Presentation varies from acute limbic encephalitis to subacute or chronic disorders of cognition mimicking neurodegenerative dementia. It may occur as a paraneoplastic phenomenon or an idiopathic autoimmune phenomenon. The presence of a personal/family history of autoimmunity, inflammatory spinal fluid, serologic evidence of autoimmunity (neural or nonorgan-specific), or mesial temporal magnetic resonance imaging abnormalities are clues to diagnosis. Bedside cognitive assessment and/or detailed neuropsychologic testing are useful. Neural-specific autoantibodies, mostly discovered in the past two decades, may bind antigens on the cell surface (e.g., N-methyl-d-aspartate receptor autoantibodies) and are likely to be pathogenic, with treatment aimed at antibody-depleting agents often with success, while antibodies binding intracellular antigens (e.g., antineuronal nuclear autoantibody type 1 (ANNA1 or anti-Hu)) are a marker of a T-cell-mediated process and treated with T-cell-depleting immunotherapies, with variable responses. Detection and treatment of cancer (when present) are essential. High-dose corticosteroids are the initial treatment in most patients and may serve as a diagnostic test when the diagnosis is uncertain. Repeat cognitive testing after immunotherapy helps document objective improvements. Maintenance immunotherapy is recommended in those at risk for relapse. Prognosis is variable, but paraneoplastic ADE with antibodies to intracellular antigens have a worse prognosis. The field is still developing and future studies should provide guidelines for diagnosis and treatments.

(18)F-FDG PET/CT and MRI findings in a patient with anti-GABA(B) receptor encephalitis

Autoimmune synaptic encephalitis can occur as paraneoplastic neurological syndromes, which are dysfunctions of the nervous system in cancer patients. One such rare but treatable form is associated with GABAB (γ-aminobutyric acid-B) receptor antibody. We report a 55-year-old man with small cell lung cancer who presented with 3 weeks of progressive seizures, memory impairment, and behavioral disorder. His cerebrospinal fluid anti-GABAB receptor antibody titer was elevated. F-FDG PET/CT revealed pronounced medial temporal hypermetabolism with gross hypometabolism in the rest of the brain. There were no associated abnormalities on MRI. He showed improvement after immunotherapy and chemoradiotherapy.

Clinical manifestations and outcomes of the treatment of patients with GABAB encephalitis

Encephalitis associated with anti-γ-aminobutyric acid-B (GABAB) receptor antibodies has been identified recently. However, only a few cases have been reported to date and its clinical manifestations and prognosis have not been investigated systematically. We identified five cases of GABAB encephalitis in Korea. Here we present the clinical features, treatment responses, and brain positron emission tomography findings of the cases. The patients had a clinical triad of memory changes, seizure, and association with small-cell lung cancer. Early diagnosis and comprehensive immune modulation may provide a good outcome.

Chorea, a little-known manifestation in systemic lupus erythematosus: short literature review and four case reports

Chorea is a movement disorder that may be found in children due to several causes. Here we focus especially on Systemic Lupus Erythematosus associated chorea. First we outline its epidemiology, hypothesized pathogenesis, clinical presentation and treatment, then we report four significant clinical cases, which represent well the extreme variability of set of symptoms that may accompany lupus chorea. Our experience, according to literature, suggests that choreic movements in a child should alert the pediatrician and lead him to investigate a potential neurological involvement of Systemic Lupus Erythematosus.

18F-FDG PET/CT findings in voltage-gated potassium channel limbic encephalitis

Limbic encephalitis (LE) can be associated with cancer, viral infection, or be idiopathic. One such rare but treatable form is associated with voltage-gated potassium channel (VGKC) antibodies. Typical abnormalities are seen in FDG PET/CT. We report a 39-year-old female patient who presented with 3 months of progressive faciobrachial dystonic seizures and limbic encephalitis. Her serum and cerebrospinal fluid Lgi1 antibody titers were elevated. FDG PET/CT showed basal ganglial hypermetabolism and associated abnormalities. Serial MRI demonstrated atrophic changes predominantly involving the temporal lobes. She is on immunosuppressive therapy and shows clinical improvement with lowering of antibody titers.

Semiquantitative analysis of brain metabolism in patients with paraneoplastic neurologic syndromes

PURPOSE

The objective of this study was to evaluate brain metabolism with F-FDG-PET in patients with definite or possible paraneoplastic neurologic syndromes (PNS) using qualitative assessment and semiquantitative measurements with subsequent correlation with MRI.

METHODS

The institutional review board approved this Health Insurance Portability and Accountability Act-compliant study. A prospective PET database of patients referred for PNS between 2001 and 2010 was queried retrospectively and identified 102 patients who met the diagnostic criteria for PNS, had PET brain imaging, and lacked clinical or MRI evidence of an alternative diagnosis.Qualitative and semiquantitative evaluation of brain metabolism was obtained by 3-dimensional stereotactic surface projection and region-based analysis. Qualitative and semiquantitative assessment was performed blinded to clinical data.

RESULTS

PET/CT demonstrated that 67 patients had abnormal brain glucose metabolism. Six categories of brain hypometabolism were identified: diffuse (36/67), cerebellar (10/67), basal ganglia (10/67), frontal (9/67), temporal (1/67), and occipital (1/67). The mean Z score of the cerebral cortex in diffuse hypometabolism was 1.65 (range, 0.25-3.46). For cerebellar hypometabolism, the mean Z score of the cerebellum was 2.31 (range, 0.52-4.54). In basal ganglia hypometabolism, the mean Z score was 2.53 (range, 1.78-3.89), and in frontal lobe hypometabolism, the mean Z score was 2.11 (range, 1.39-4.45). The majority (39/67, 62.9%) with abnormal glucose metabolism on PET had a normal MR.

CONCLUSIONS

Patients with PNS frequently have abnormal brain metabolism on semiquantitative PET/CT. With semiquantitative analysis, we defined 6 common patterns of abnormalities, which often correlated with clinical symptoms. Both qualitative and semiquantitative analyses of brain glucose metabolism may be helpful in evaluating PNS, especially in patients with a normal MRI.

Movement disorders in systemic lupus erythematosus and the antiphospholipid syndrome

Movement disorders (MDs), particularly chorea, may be the presenting neurological complication of systemic lupus erythematosus (SLE) and the antiphospholipid syndrome (APS), but the association is not often initially recognized. Current evidence suggests an autoimmune mechanism related to antiphospholipid antibodies in these two conditions, although the antigenic target within the central nervous system has not yet been identified. Based on a comprehensive review of the literature, this article summarizes the current knowledge on MDs in SLE and APS. A high index of suspicion is required to make an early diagnosis and initiate appropriate treatment to provide symptomatic relief and to prevent other systemic complications related to the autoimmune process.