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Objective/Background: Neurological complications occur at a high frequency after hematopoietic cell transplantation (HCT). However, an absence is noted in the published literature as regards the quantification of the exact burden and the outcomes thereof. In this systematic review, we endeavored to detail if the recipients of HCT developed any noninfectious neurological events/complications. Methods According to the PICO criteria, medical literature was searched. Complications that were evaluated included: stroke, peripheral neuropathy, myasthenia gravis, seizures, and posterior reversible encephalopathy syndrome. After strictly defining relevant variables and parameters, data from 173 eligible articles were then extracted accordingly, from the full text for each, for quantitative analysis; additionally, two American Society of Hematology conference abstracts were also subject to data extraction. Results As is evident from the results of the data analysis, an increased frequency of these complications was seen in the HCT recipient population in comparison to the general population. The relative risk ranged from 1.33× to 142× depending on the complication studied. Conclusion These findings demonstrate that the recipients of HCT had a significantly higher risk of neurological complications and that their early recognition can enhance the monitoring of HCT survivors for the early developmental signs of neurological toxicity. This would facilitate timely interventions, thus ensuring a better quality of life.

ObjectiveTo determine whether MRI gadolinium enhancement patterns in myelopathies with longitudinally extensive T2 lesions can be reliably distinguished and assist in diagnosis.MethodsWe retrospectively identified 74 Mayo Clinic patients (January 1, 1996–December 31, 2019) fulfilling the following criteria: (1) clinical myelopathy; (2) MRI spine available; (3) longitudinally extensive T2 hyperintensity (≥3 vertebral segments); and (4) characteristic gadolinium enhancement pattern associated with a specific myelopathy etiology. Thirty-nine cases with alternative myelopathy etiologies, without previously described enhancement patterns, were included as controls. Two independent readers, educated on enhancement patterns, reviewed T2-weighted and postgadolinium T1-weighted images and selected the diagnosis based on this knowledge. These were compared with the true diagnoses, and agreement was measured with Kappa coefficient.ResultsAmong all cases and controls (n = 113), there was excellent agreement for diagnosis using postgadolinium images (kappa, 0.76) but poor agreement with T2-weighted characteristics alone (kappa, 0.25). A correct diagnosis was more likely when assessing postgadolinium image characteristics than with T2-weighted images alone (rater 1: 100/113 [88%] vs 61/113 [54%] correct, p < 0.0001; rater 2: 95/113 [84%] vs 68/113 [60%] correct, p < 0.0001). Of the 74 with characteristic enhancement patterns, 55 (74%) were assigned an alternative incorrect or nonspecific diagnosis when originally evaluated in clinical practice, 12 (16%) received immunotherapy for noninflammatory myelopathies, and 2 (3%) underwent unnecessary spinal cord biopsy.ConclusionsMisdiagnosis of myelopathies is common. The gadolinium enhancement patterns characteristic of specific diagnoses can be identified with excellent agreement between raters educated on this topic. This study highlights the potential diagnostic utility of enhancement patterns in myelopathies with longitudinally extensive T2 lesions.

A 77-year-old man presented with 1 week of back pain, night sweats, confusion, jaundice, and pruritus with patchy, blanchable erythematous lesions over his trunk (figure 1). Neurologic examination was normal, but a lumbar spine MRI showed diminished bone marrow signal. He was thrombocytopenic (13 × 109/L) and anemic (7.2 g/dL) with an immunoglobulin M (IgM) kappa monoclonal gammopathy and bone marrow biopsy consistent with Waldenstrom macroglobulinemia (WM). He was initiated on 60 mg prednisone daily and rituximab. Skin biopsy revealed nonspecific dermal edema with perivascular inflammation. Two weeks into admission, he developed left lower motor neuron facial droop, and was kept on the prednisone started 2 days prior for his WM. Shortly after that, it was noted that his Borrelia burgdorferi enzyme immunoassay (EIA) screen and supplemental B burgdorferi IgM immunoblot were positive, while the immunoglobulin G immunoblot was negative. Three weeks later, his facial palsy had resolved, but given extensive tick exposure history, he was treated with 3 weeks of doxycycline. CSF collection was deferred due to thrombocytopenia.

Autoimmune encephalitis (AE) is a potentially treatable cause of rapidly progressive dementia that may mimic Creutzfeldt-Jakob disease (CJD). Alzheimer disease (AD) cerebrospinal fluid (CSF) biomarkers may discriminate CJD from AD, but utility in discriminating CJD and AE is unclear. This study compared AD CSF biomarkers in CJD and AE.Patients with probable or definite CJD and probable or definite AE who underwent Roche Elecsys AD CSF biomarker testing at Mayo Clinic from March 2020 through April 2021 were included. Total-tau, phosphorylatedOf 11 CJD cases, four were autopsy proven; the rest had positive real-time quaking-induced conversion testing. Disease-associated autoantibodies were detected in 8/15 cases of AE: leucine-rich glioma-inactivated 1 and neuronal intermediate filaments (two cases each), and N-methyl-d-aspartate receptor, contactin-associated protein-like 2, dipeptidyl-peptidase-like protein 6 and immunoglobulin-like cell adhesion molecule IgLON family member 5. Total-tau provided excellent discrimination between CJD and AE in a univariate model (odds ratio 1.46 per 100 pg/ml, 95% confidence interval 1.17-2.11, p 0.05, c = 0.93). Total-tau was elevated in 91% of CJD cases (median 1300, range 236-1300 pg/ml), of which 55% were above the limit of assay measurement (1300 pg/ml). Total-tau was elevated in 20% of AE cases (median 158, range 80-1300 pg/ml).Total-tau was greater in CJD than AE. Given that amyloid-β

BACKGROUND Hyperammonemia is a common side effect of valproic acid (VPA) and can occur after generalized seizures, but the clinical significance is unclear. The aim of this study was to better understand the clinical practice and utility of ammonia testing in status epilepticus (SE) treated with or without VPA. METHODS Charts of adult patients with SE from St. Mary's Hospital Intensive Care Units (ICUs) (Mayo Clinic, Rochester, MN) from 2011 to 2016 were reviewed. Clinical factors were compared between patients who had ammonia checked versus those who did not, and those with normal ammonia versus hyperammonemia (>50 µg/dL). Charts were reviewed to determine if hyperammonemia changed clinical management and if it was felt to be symptomatic. RESULTS There were 304 patients identified: 94 received VPA, 142 had ammonia checked and receiving VPA was associated with ammonia testing (P

ImportanceAutoimmune encephalitis misdiagnosis can lead to harm.ObjectiveTo determine the diseases misdiagnosed as autoimmune encephalitis and potential reasons for misdiagnosis.Design, Setting, and ParticipantsThis retrospective multicenter study took place from January 1, 2014, to December 31, 2020, at autoimmune encephalitis subspecialty outpatient clinics including Mayo Clinic (n = 44), University of Oxford (n = 18), University of Texas Southwestern (n = 18), University of California, San Francisco (n = 17), Washington University in St Louis (n = 6), and University of Utah (n = 4). Inclusion criteria were adults (age ≥18 years) with a prior autoimmune encephalitis diagnosis at a participating center or other medical facility and a subsequent alternative diagnosis at a participating center. A total of 393 patients were referred with an autoimmune encephalitis diagnosis, and of those, 286 patients with true autoimmune encephalitis were excluded.Main Outcomes and MeasuresData were collected on clinical features, investigations, fulfillment of autoimmune encephalitis criteria, alternative diagnoses, potential contributors to misdiagnosis, and immunotherapy adverse reactions.ResultsA total of 107 patients were misdiagnosed with autoimmune encephalitis, and 77 (72%) did not fulfill diagnostic criteria for autoimmune encephalitis. The median (IQR) age was 48 (35.5-60.5) years and 65 (61%) were female. Correct diagnoses included functional neurologic disorder (27 [25%]), neurodegenerative disease (22 [20.5%]), primary psychiatric disease (19 [18%]), cognitive deficits from comorbidities (11 [10%]), cerebral neoplasm (10 [9.5%]), and other (18 [17%]). Onset was acute/subacute in 56 (52%) or insidious (>3 months) in 51 (48%). Magnetic resonance imaging of the brain was suggestive of encephalitis in 19 of 104 patients (18%) and cerebrospinal fluid (CSF) pleocytosis occurred in 16 of 84 patients (19%). Thyroid peroxidase antibodies were elevated in 24 of 62 patients (39%). Positive neural autoantibodies were more frequent in serum than CSF (48 of 105 [46%] vs 7 of 91 [8%]) and included 1 or more of GAD65 (n = 14), voltage-gated potassium channel complex (LGI1 and CASPR2 negative) (n = 10), N-methyl-d-aspartate receptor by cell-based assay only (n = 10; 6 negative in CSF), and other (n = 18). Adverse reactions from immunotherapies occurred in 17 of 84 patients (20%). Potential contributors to misdiagnosis included overinterpretation of positive serum antibodies (53 [50%]), misinterpretation of functional/psychiatric, or nonspecific cognitive dysfunction as encephalopathy (41 [38%]).Conclusions and RelevanceWhen evaluating for autoimmune encephalitis, a broad differential diagnosis should be considered and misdiagnosis occurs in many settings including at specialized centers. In this study, red flags suggesting alternative diagnoses included an insidious onset, positive nonspecific serum antibody, and failure to fulfill autoimmune encephalitis diagnostic criteria. Autoimmune encephalitis misdiagnosis leads to morbidity from unnecessary immunotherapies and delayed treatment of the correct diagnosis.

ObjectiveWe aim to describe the clinical, laboratory, and radiographic features that characterize patients with progressive multifocal leukoencephalopathy (PML) in the context of sarcoidosis (S-PML).BackgroundSarcoidosis has been associated with CD4+, CD8+, and CD19+ lymphopenia, T-cell anergy, and increased infection risk. S-PML has been reported in approximately 60 cases. PML is often mistaken for neurosarcoidosis, leading to harmful administration of high-dose steroids. Preliminary evidence suggests that experimental therapies such as interleukins 2 and 7, checkpoint inhibitors, polyomavirus-specific T-cell therapy, and infliximab may offer promise for treatment. To ensure optimal outcome, it is crucial to identify S-PML accurately and with minimal delay.Design/MethodsData and imaging for patients were collected retrospectively from the electronic medical record from Mass General-Brigham network hospitals, National Institutes of Health, Mayo Clinic, Columbia University Irving Medical Center, University of California San Francisco, University of Michigan, and Beth Israel Deaconess Medical Center.ResultsTwenty-five patients with definite S-PML were identified. Median age at diagnosis of sarcoidosis was 54 years, and median time between sarcoidosis and PML diagnosis was 12 months. Sarcoidosis was isolated to lung in 14/25 patients; 10/25 had multisystem involvement; one patient had isolated dermatologic sarcoidosis. Of all patients, 16/25 patients had never received immunosuppressive medications prior to neurological symptom onset. Median serum lymphocyte count at time of PML diagnosis was 430 cells/uL (range: 50-1490). On MRI, 8/25 patients had infratentorial lesions only, while 8/25 had both infratentorial and supratentorial lesions, and 6/25 showed contrast enhancement. Seven/twenty-five patients progressed to death.ConclusionsThis study characterizes the clinical, laboratory, and imaging features of S-PML patients from seven major US medical centers. These data will be used to identify risk factors for development of PML in the context of sarcoidosis and to investigate any biomarkers that might aid in accurate and timely diagnosis.

ObjectiveTo determine the diseases misdiagnosed as AE and potential reasons for misdiagnosis.BackgroundMisdiagnosis of autoimmune encephalitis (AE) may harm patients.Design/MethodsPatients with AE misdiagnosis were identified (1/1/2014-12/31/2020) from outpatient AE subspecialty clinics including: Mayo Clinic (n = 44); Oxford (n = 18); UT Southwestern (n = 18); UCSF (n = 17); Washington University (n = 6); University of Utah (n = 4). Inclusion criteria were adults (=18 years) with: 1) A prior diagnosis of AE; and 2) An alternative diagnosis made at a participating center. We collected data on clinical features, investigations, fulfillment of possible AE criteria, alternative diagnoses, and potential contributors to misdiagnosis.ResultsWe identified 107 patients misdiagnosed with AE. Thirty (28%) fulfilled diagnostic criteria for “possible AE”. Median onset age was 48 years (inter-quartile range, 35.5-60.5) and 65 (61%) were female. Correct diagnoses included: functional neurologic disorder, 27 (25%); neurodegenerative disease, 22 (21%); primary psychiatric disease, 19 (18%); cognitive deficits from comorbidities, 11 (10%); cerebral neoplasm, 10 (9%); and other, 18 (17%). Onset was insidious (>3 months) in 51 (48%). MRI brain was suggestive of encephalitis in 19/104 (18%) and CSF pleocytosis occurred in 16/84 (19%). Thyroid-peroxidase antibodies were elevated in 24/62 (39%). Positive neural autoantibodies were more frequent in serum (48/105[46%]) than CSF (7/91[8%]; pConclusionsRed flags suggesting alternative diagnoses to AE include lack of fulfillment of “possible autoimmune encephalitis” criteria, positive non-specific serum antibody, and insidious onset. Avoiding AE misdiagnosis will prevent morbidity from unnecessary immunotherapies and delayed treatment of the correct diagnosis.

Bacterial infections of the nervous system manifest themselves in several ways, most of which are neurologic emergencies. This chapter reviews the classic syndromes of meningoencephalitis and focal infection (cerebritis or abscess) and the syndromes of neurosyphilis, tuberculosis, botulism, leprosy, Lyme disease, Whipple disease, rickettsiosis, diphtheria, and ventricular shunt infections.

A 62-year-old woman sought care in late summer for a 4-day history of upper respiratory tract symptoms, intermittent fevers, headache, and a 1-day history of disorientation, word-finding difficulties, and unsteady gait. Upon arrival to the emergency department, she had a witnessed seizure and was intubated because of increased lethargy. Her temperature was 39.4 °C, but she was otherwise hemodynamically stable. She had normal ophthalmoscopic examination findings and antigravity strength in all 4 extremities. Her deep tendon reflexes were brisk, but plantar responses were flexor. She had no rash. Cerebrospinal fluid analysis showed a normal glucose value, protein concentration of 82 mg/dL, and mixed pleocytosis. She had been hiking recently, but her family reported that there were no tick exposures or mosquito bites. Brain magnetic resonance imaging showed areas of T2 fluid-attenuated inversion recovery hyperintensity involving primarily the left thalamus and basal ganglia without definitive gadolinium enhancement. Both serum and cerebrospinal fluid were positive for immunoglobulin M antibodies to West Nile virus. The patient was diagnosed with West Nile virus encephalitis. After the seizure, the patient was treated with levetiracetam, and empiric antimicrobials were started for acute meningoencephalitis, along with adjunctive dexamethasone. Continuous electroencephalography was obtained because of the persistent encephalopathy and showed no evidence of subclinical seizures. The dexamethasone was stopped after 2 doses because of low suspicion for pneumococcal meningitis, and the antibiotics were discontinued after results of serum and cerebrospinal fluid cultures were negative for bacteria (48 hours). Acyclovir was stopped after the polymerase chain reaction results were negative for herpes simplex virus and varicella-zoster virus.

A 47-year-old woman with a history of relapsing-remitting multiple sclerosis (MS) receiving natalizumab therapy sought a second opinion regarding a recent diagnosis of secondary progressive disease. She was first diagnosed with multiple sclerosis 8 years earlier. While taking natalizumab, she was monitored for the development of antibodies to JC polyoma virus. Nine months before our evaluation, anti-JC polyoma virus antibodies became positive, with an increased index of 1.1. Given sustained remission, she was continued on natalizumab with increased surveillance and a plan to switch to a different disease-modifying therapy after 24 months. Five months later she noted subacute onset of slurred speech and right upper extremity incoordination. Over the next 4 months she continued to have clinical decline. On examination she had moderate ataxic dysarthria and right greater than left appendicular ataxia. She relied on a wheelchair for transportation and required 1-person assist to stand. Reflexes were brisk with bilateral Babinski sign. This patient with relapsing-remitting multiple sclerosis on natalizumab had a new subacute progressive cerebellar syndrome without radiographic evidence of disease activity. Repeated magnetic resonance imaging showed worsening cerebellar atrophy, right sided greater than left sided, and evolving T2 hyperintensity in the brainstem without enhancement or mass effect. JC polyoma virus polymerase chain reaction was positive. The patient was diagnosed with JC polyoma virus granule cell neuronopathy. Natalizumab was discontinued, and she was treated with 4 of 5 planned cycles of plasma exchange. After her 4th cycle, worsening symptoms developed. Magnetic resonance imaging showed gadolinium enhancement in the brainstem supportive of immune reconstitution inflammatory syndrome. She received high-dose intravenous methylprednisolone followed by a prednisone taper. Her disability progression stabilized. JC polyoma virus central nervous system infection, 1 of several infections reported among treated patients with multiple sclerosis, occurs almost exclusively in immunosuppressed patients, including those receiving disease-modifying therapy for multiple sclerosis.

A 52-year-old man is admitted to a neurosciences intensive care unit during winter for management of seizures requiring mechanical ventilation. Two days earlier he reported cough and myalgia. He was found seated on the couch with altered mental state and was minimally responsive. Upon arrival to the emergency department he was febrile at 38.8 °C and tachycardic. Complete blood cell count showed leukocytosis (11.1×109 cells/L, neutrophilic predominance). Computed tomography of the head showed an area of hypodensity in the left temporal lobe. During computed tomography, the patient had generalized convulsions requiring lorazepam, fosphenytoin, and levetiracetam, followed by initiation of a continuous midazolam infusion before seizures were controlled. He was started on broad-spectrum antimicrobials, including acyclovir, and a lumbar puncture was performed. Cerebrospinal fluid protein concentration was 196 mg/dL, and he had 10 white blood cells/µL with lymphocyte predominance. There was no hypoglycorrhachia. After 24 hours, the patient was weaned from the midazolam infusion and maintained on levetiracetam monotherapy. He was extubated but remained encephalopathic. Magnetic resonance imaging performed the day after admission demonstrated numerous T2 hyperintense lesions throughout both cerebral hemispheres including both mesial temporal lobes and right thalamus. Nasopharyngeal polymerase chain reaction was positive for influenza virus A, which was later typed further and identified as pandemic 2009 H1N1 virus. A diagnosis of influenza-associated encephalopathy/encephalitis was made. The patient was treated with oseltamivir, as well as high-dose intravenous methylprednisolone. His encephalopathy gradually improved. Repeated imaging at 3-month follow-up showed resolution of the previously seen abnormalities. His neurologic examination was normal. Postinfectious or parainfectious autoimmunity syndromes refer to neurologic signs and symptoms that develop during or after an infection but are not thought to be caused by direct infection of the nervous system.

Parasitic infections make up a small but important subset of central nervous system (CNS) infections. Although necessary to be considered in the comprehensive differential diagnosis for patients presenting with suspected neurologic infections, these conditions are particularly important in regions where parasitic infections are endemic and for immunocompromised patients. Among the most common parasitic infections of the CNS are neurocysticercosis, echinococcosis (hydatid cyst), toxoplasmosis, amebic meningoencephalitis, and cerebral malaria.

ObjectiveTo compare acute treatment responses and long-term outcome in leucine-rich glioma-inactivated 1 (LGI1) antibody encephalitis.MethodsRetrospective case series of 118 patients with LGI1 antibody encephalitis evaluated at Mayo Clinic across all US sites from 1 May 2008 to 31 March 2019. Patient clinical data were identified and analysed through the neuroimmunology laboratory and electronic medical record. LGI1 antibody detection was by cell-based indirect immunofluorescence assay of serum, cerebrospinal fluid or both. Clinical outcomes were faciobrachial dystonic seizure (FBDS) resolution, modified Rankin Scale (mRS) score, Kokmen Short Test of Mental Status (STMS) score (0–38 point scale) and neuropsychometric testing results.ResultsCompared with intravenous immunoglobulin (IVIg) (n=21), patients treated with single-agent acute corticosteroids (intravenous, oral or both) (n=49) were more likely to experience resolution of FBDS (61% vs 7%, p=0.002) and improvements in mRS score (ΔmRS score 2 vs 0, p=0.008) and median Kokmen STMS scores (ΔKokmen STMS score 5 points vs 0 points, p=0.01). In 54 patients with long-term follow-up (≥2 years), the median mRS score was 1 (range 0–6) and the median Kokmen STMS score was 36 (range 24–38) after all combinations of immunotherapy. Neuropsychometric testing in 32 patients with long-term follow-up (≥2 years) demonstrated short-term memory impairments in 37%.ConclusionsCorticosteroids appeared more effective acutely than IVIg in improving LGI1 antibody encephalitis in this retrospective comparison of immunotherapies. While improvement with immunotherapy is typical and long-term outcome is favourable, short-term memory deficits are noted in approximately a third of the patients.

Background and ObjectiveSevere attacks of myelin oligodendrocyte glycoprotein (MOG) antibody–associated disorder (MOGAD) and aquaporin-4 (AQP4) antibody–positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) may require ventilatory support, but data on episodes are limited, particularly for MOGAD. We sought to compare the frequency, characteristics, and outcomes of MOGAD and AQP4-NMOSD attacks requiring ventilatory support.MethodsThis retrospective descriptive study identified Mayo Clinic patients (January 1, 1996–December 1, 2020) with MOGAD or AQP4-NMOSD and an attack requiring noninvasive or invasive ventilation at Mayo Clinic or an outside facility by searching for relevant terms in their electronic medical record. Inclusion criteria were (1) attack-related requirement for noninvasive (bilevel positive airway pressure or continuous positive airway pressure) or invasive respiratory support (mechanical ventilation); (2) MOG or AQP4 antibody positivity with fulfillment of MOGAD and AQP4-NMOSD clinical diagnostic criteria, respectively; and (3) sufficient clinical details. We collected data on demographics, comorbid conditions, indication for and duration of respiratory support, MRI findings, treatments, and outcomes. The races of those with attacks requiring respiratory support were compared to those without such attacks in MOGAD and AQP4-NMOSD.ResultsAttacks requiring ventilatory support were similarly rare in patients with MOGAD (8 of 279, 2.9%) and AQP4-NMOSD (11 of 503 [2.2%]) (p= 0.63). The age at attack (median years [range]) (MOGAD 31.5 [5–47] vs AQP4-NMOSD 43 [14–65];p= 0.01) and percentage of female sex (MOGAD 3 of 8 [38%] vs AQP4-NMOSD 10 of 11 [91%];p= 0.04) differed. The reasons for ventilation differed between MOGAD (inability to protect airway from seizure, encephalitis or encephalomyelitis with attacks of acute disseminated encephalomyelitis 5 [62.5%] or unilateral cortical encephalitis 3 [37.5%]) and AQP4-NMOSD (inability to protect airway from cervical myelitis 9 [82%], rhombencephalitis 1 [9%], or combinations of both 1 [9%]). Median ventilation duration for MOGAD was 2 days (range 1–7 days) vs 19 days (range 6–330 days) for AQP4-NMOSD (p= 0.01). All patients with MOGAD recovered, but 2 of 11 (18%) patients with AQP4-NMOSD died of the attack. For AQP4-NMOSD, Black race was overrepresented for attacks requiring ventilatory support vs those without these episodes (5 of 11 [45%] vs 88 of 457 [19%];p= 0.045).DiscussionVentilatory support is rarely required for MOGAD and AQP4-NMOSD attacks, and the indications differ. Compared to MOGAD, these attacks in AQP4-NMOSD may have higher morbidity and mortality, and those of Black race were more predisposed, which we suspect may relate to socially mediated health inequality.

PURPOSE OF REVIEW: This article reviews infectious etiologies of spinal cord dysfunction, emphasizing the importance of recognizing common clinicoradiographic syndromes and interpreting them in the context of exposure risk and individual host susceptibilities. RECENT FINDINGS: This article discusses the shifting spectrum of neurologic infectious diseases, the growing population of patients who are immunocompromised, and the emergence of effective antiretroviral therapies. In addition, it discusses new molecular and serologic tests that have the potential to enhance our ability to rapidly and accurately diagnose infectious diseases of the spine. SUMMARY: When evaluating patients with suspected infectious myelopathies, it is imperative to narrow the range of pathogens under consideration. The geography, seasonality, and clinicoradiographic presentation and immunocompetence status of the patient define the range of potential pathogens and should guide testing and initial management.

The original version contained incorrect formatting of Dr. Napolis. His first name should be Mario and his last name should be Di Napoli.

PURPOSE OF REVIEW: Coronavirus disease 2019 (COVID-19) has become a global health crisis of our time. The disease arises from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that binds to angiotensin-converting enzyme 2 (ACE2) receptors on host cells for its internalization. COVID-19 has a wide range of respiratory symptoms from mild to severe and affects several other organs, increasing the complexity of the treatment. There is accumulating evidence to suggest that SARS-CoV-2 can target the nervous system. In this review, we provide an account of the COVID-19 central nervous system (CNS) manifestations.RECENT FINDINGS: A broad spectrum of the CNS manifestations including headache, impaired consciousness, delirium, loss of smell and taste, encephalitis, seizures, strokes, myelitis, acute disseminated encephalomyelitis, neurogenic respiratory failure, encephalopathy, silent hypoxemia, generalized myoclonus, neuroleptic malignant syndrome and Kawasaki syndrome has been reported in patients with COVID-19. CNS manifestations associated with COVID-19 should be considered in clinical practice. There is a need for modification of current protocols and standing orders to provide better care for COVID-19 patients presenting with neurological symptoms.

Peripheral neuropathies secondary to neurotoxicants are frequently considered but can be difficult to diagnose. Accurate diagnosis is important to avoid unnecessary testing, prevent further exposure, and initiate treatment when available. This article reviews key features of some of the more common or representative toxic neuropathies, including those caused by occupational and environmental exposure, medications, and chemotherapeutic agents.

Shotgun metagenomic sequencing can detect nucleic acids from bacteria, fungi, viruses, and/or parasites in clinical specimens; however, little data exist to guide its optimal application to clinical practice. We retrospectively reviewed results of shotgun metagenomic sequencing testing requested on cerebrospinal fluid samples submitted to an outside reference laboratory from December 2017 through December 2019. Of the 53 samples from Mayo Clinic patients, 47 were requested by neurologists, with infectious diseases consultation in 23 cases. The majority of patients presented with difficult-to-diagnose subacute or chronic conditions. Positive results were reported for 9 (17%) Mayo Clinic patient samples, with 6 interpreted as likely contamination. Potential pathogens reported included bunyavirus, human herpesvirus 7, and enterovirus D-68, ultimately impacting care in two cases. Twenty-seven additional samples were submitted from Mayo Clinic Laboratories reference clients, with positive results reported for three (11%): two with potential pathogens (West Nile virus and Toxoplasma gondii) and one with Streptococcus species with other bacteria below the reporting threshold (considered to represent contamination). Of 68 negative results, 10 included comments on decreased sensitivity due to high DNA background (n = 5), high RNA background (n = 1), insufficient RNA read depth (n = 3), or quality control (QC) failure with an external RNA control (n = 1). The overall positive-result rate was 15% (12/80), with 58% (7/12) of these interpreted as being inconsistent with the patient’s clinical presentation. Overall, potential pathogens were found in a low percentage of cases, and positive results were often of unclear clinical significance. Testing was commonly employed in cases of diagnostic uncertainty and when immunotherapy was being considered.

BACKGROUND: Inappropriate use of diagnostic tests contributes to rising healthcare expenditures, and improving appropriate utilization rates is important for high-value patient care. The Venereal Disease Research Laboratory (VDRL) test performed in cerebrospinal fluid (CSF) has historically been improperly utilized, although there is no recent evaluation of its use in clinical practice. OBJECTIVES: Quantify the rates of appropriate CSF-VDRL testing, determine the CSF-VDRL false-positivity rate, and describe the causes of false-positive CSF-VDRL reactivity. DESIGN: Retrospective cohort study PATIENTS: A total of 32,626 patients with CSF-VDRL testing at one of three Mayo Clinic sites (Rochester, MN; Jacksonville, FL; and Scottsdale, AZ) from January 1, 1994, to February 28, 2018. MAIN MEASURES: Rate of appropriate CSF-VDRL test utilization from January 1, 2011, to December 31, 2017, and CSF-VDRL true- and false-positivity rates from January 1, 1994, to February 28, 2018. KEY RESULTS: Among 8553 persons with negative CSF-VDRL results, testing was inappropriately ordered for 8399 (98.2%) of these patients. The word “syphilis” or “neurosyphilis” appeared in the notes of 1184 (13.8%) individuals with a negative CSF-VDRL result. From January 1994 through February 2018, 33,933 CSF-VDRL tests were performed on 32,626 individual patients. Among the 60 positive CSF-VDRL results, 43 (71.7%) were true-positives and 17 (28.3%) were false-positives. All patients with false-positive CSF-VDRL results were tested unnecessarily. Neoplastic meningitis was a common cause of false-positive CSF-VDRL results. CONCLUSIONS: Inappropriate use of CSF-VDRL testing for the diagnosis of neurosyphilis remains problematic in clinical practice. Following recommended testing algorithms would prevent unnecessary testing and minimize false-positive results.

Background: Episodic hypothermia (EH) can occur in multiple sclerosis (MS). The putative mechanism is impairment of thermoregulation due to a presumed demyelinating hypothalamic lesion. Objective: To describe a cohort of patients with MS, who developed EH. Methods: Patients were identified through review of the Mayo Clinic electronic medical record (1996 to July 2015). Search terms were [multiple sclerosis] or [MS] within the diagnoses field and [hypothermia] within any field. We reviewed records for accuracy of diagnoses and abstracted relevant data. Magnetic resonance imaging (MRI) was reviewed for presence of hypothalamic lesions. Results: Of 156 patients, 34 had concurrent MS and hypothermia. Thirty-two (94%) had progressive disease at EH onset. Median MS duration was 19.9 years, and median expanded disability status scale (EDSS) was 8.0. Most patients presented with alterations in consciousness. Infection was suspected as the precipitating factor in 19 (56%), but clinically/laboratory supported in only 9 (28%). MRI lesions were evident within the hypothalamus in only 4 (14%). Conclusion: EH occurs predominantly in patients with advanced secondary progressive MS. The major manifestation is altered consciousness. Infection is often suspected as causal, but infrequently confirmed. Although commonly implicated, hypothalamic lesions were rarely evident on MRI and were absent in two post-mortem evaluations.

Objectives We evaluate incidence and prevalence of autoimmune encephalitis and compare the epidemiology of autoimmune and infectious encephalitis.

Background The Venereal Disease Research Laboratory (VDRL) test performed in cerebrospinal fluid (CSF) is considered highly specific for the diagnosis of neurosyphilis, but algorithms to diagnose neurosyphilis require positive syphilis serologic testing prior to obtaining CSF-VDRL. Inappropriate use of diagnostic tests depletes healthcare resources, and contributes to rising healthcare expenditures. CSF-VDRL has historically been improperly utilized; however there is no recent evaluation of its use in clinical practice. We aimed to quantify rates of appropriate CSF-VDRL testing, determine the CSF-VDRL false-positivity rate and describe causes of false-positive CSF-VDRL reactivity. Methods In this retrospective cohort study of three Mayo Clinic sites (Rochester, MN, Jacksonville, FL, and Scottsdale, AZ), we measured the rate of appropriate CSF-VDRL test utilization in patients with negative testing from January 1, 2011 to December 31, 2017. We then identified all patients with positive CSF-VDRL testing from January 1, 1994 to February 28, 2018, characterized true- and false-positive rates and described causes of CSF-VDRL false-positivity. Results Among 8,553 persons with negative CSF-VDRL results, testing was unnecessarily ordered in 8,399 (98.2%). The word “syphilis” or “neurosyphilis” appeared in the notes of only 1,184 (13.8%) individuals with a negative CSF-VDRL result. From January 1994 through February 2018, 33,933 CSF-VDRL tests were performed on 32,626 individual patients. Among 60 positive CSF-VDRL results, 41 (68.3%) were true-positives, 2 (3.3%) were indeterminate, and 17 (28.3%) were false-positives. Every patient with true-positive CSF-VDRL had positive serologic syphilis testing prior to CSF testing. All patients with false-positive CSF-VDRL results were inappropriately tested. Neoplastic meningitis was a common cause of false-positive CSF-VDRL results. Conclusion This is the first study in decades to review CSF-VDRL utilization for the diagnosis of neurosyphilis. Inappropriate use of CSF-VDRL testing for diagnosis of neurosyphilis remains problematic in clinical practice. Following recommended testing algorithms would prevent unnecessary testing, preserve resources, and minimize false-positive results. Disclosures All Authors: No reported disclosures

Early recognition of an infectious syndrome and initiation of appropriate treatment improves outcome. Yet, in spite of advances in diagnosis and treatment, infections of the central nervous system (CNS) still result in significant morbidity and mortality. Choosing appropriate diagnostic studies can expedite diagnosis, avoid exposure to unnecessary invasive testing, and reduce costs of care. Awareness and early detection of known complications of CNS infections can decrease morbidity. Here we review common and rare infections that can result in severe neurologic compromise. We use a syndromic approach, emphasizing practical aspects of diagnosis and management.

Click here to listen to the Podcast 'Query encephalitis' is a common neurological consultation in hospitalised patients. Identifying the syndrome is only part of the puzzle. Although historically encephalitis has been almost synonymous with infection, we increasingly recognise parainfectious or postinfectious as well as other immune-mediated causes. We must also distinguish encephalitis from other causes of encephalopathy, including systemic infection, metabolic derangements, toxins, inherited metabolic disorders, hypoxia, trauma and vasculopathies. Here, we review the most important differential diagnoses (mimics) of patients presenting with an encephalitic syndrome and highlight some unusual presentations (chameleons) of infectious encephalitis.

Background GFAP (glial fibrillary acidic protein)-IgG is predominantly associated with meningoencephalomyelitis, and neuropathy presentations are rare. Methods We reviewed clinical, electrodiagnostic and histopathological presentations of GFAP-IgG associated peripheral neuropathy. Results We identified six cases, five of whom had peripheral neuropathy as the initial presentation. Acute/subacute polyradicluoneuropathy or proximal nerve involvement was a common presentation. Three had demyelinating neuropathies on electrophysiological studies. Nerve biopsies (n = 2) demonstrated T-cell predominant perivascular inflammatory collections, and all patients with clinical follow up responded favorably to immunotherapy. Conclusion GFAP neuropathy represents a potentially treatable immune-mediated neuropathy and can occur with or without co-existing meningoencephalomyelitis.

Introduction Elsberg syndrome (ES) is a rarely recognized cause of cauda equina syndrome and lower thoracic myelitis, mainly linked to reactivation, or occasionally primary, infection with herpes simplex virus type 2. West Nile virus neuroinvasive disease is rarely considered in the differential diagnosis of patients with ES. Case report A 63-year-old man with pancreatic cancer in remission and polymyalgia rheumatica on low-dose prednisone presented with a 10-day history of low-back pain and a viral-type illness with low-grade fever, nausea, and vomiting. Days later, he developed left leg monoparesis, neurogenic bladder, and bowel. Magnetic resonance imaging of the lumbar spine revealed a hyperintense signal abnormality within the central spinal cord and conus medullaris with mild swelling of the conus. Cells, proteins, and glucose in cerebrospinal fluid were 67/mm, 70 mg/dL, and 58 mg/dL, respectively. Serology was positive for West Nile virus IgM. Nerve conduction studies and electromyography showed an acute motor neurogenic process affecting left lumbosacral segments. Conclusions West Nile virus neuroinvasive disease is an uncommon condition that should be considered in patients with ES. Determining the etiology of ES in the acute setting may avoid unnecessary diagnostic investigations and treatments.

ObjectiveTo determine the persistence of no evident disease activity (NEDA) in a population-based relapsing-remitting MS (RRMS) cohort.MethodsAll incident cases of RRMS in Olmsted County between 2000 and 2011 were identified using a medical records linkage system. Persistence of NEDA after RRMS diagnosis was determined by retrospective chart review. MRI activity, relapse, or Expanded Disability Status Scale (EDSS) worsening resulted in failure of NEDA.ResultsWe identified 93 incident cases of RRMS including 82 individuals with sufficient follow-up to determine the persistence of NEDA. There were 44 individuals not on disease-modifying therapy (DMT), whereas 37 individuals were prescribed an injectable DMT and 1 received mitoxantrone during the interval over which NEDA was maintained. NEDA was maintained by 63% at 1 year, 38% at 2 years, 19% at 5 years, and 12% at 10 years according to routine care assessment. At 10 years, there was no difference in EDSS disability among patients who maintained NEDA vs those who failed NEDA at 1 year (p = 0.3).ConclusionsNEDA infrequently persists beyond 2 years in a population-based cohort of newly diagnosed patients with RRMS.

Seizures are recognized as a common manifestation of autoimmune limbic encephalitis and multifocal paraneoplastic disorders, but accumulating evidence supports an autoimmune basis for seizures in the absence of syndromic manifestations of encephalitis. Autoimmune encephalitis and epilepsy have been linked to neural-specific autoantibodies targeting both intracellular and plasma membrane antigens. The detection of these antibodies can serve as a diagnostic marker directing physicians toward specific cancers and can assist in therapeutic decision-making, but are not necessary to establish the diagnosis. Response to an immunotherapy trial can support the diagnosis and help establish prognosis. Early recognition is important because expedited diagnosis can facilitate recovery. In this review, the authors summarize the clinical presentation, pathophysiology, and management of autoimmune epilepsies for which neural antigen-specific autoantibodies serve as diagnostic aids.

We describe clinical and diagnostic features of various autoimmune and viral encephalitis subtypes.Population-based studies have demonstrated both autoimmune and viral causes have similar prevalence and incident rates. Repertoire of autoimmune biomarkers has considerably increased with discovery of many novel neural antibodies including glial fibrillary acidic proteinα-immunoglobulin G. Similarly, with use of next generation sequencing and DNA libraries, many viral causes are being detected which would have been categorized as encephalitis of unknown cause a decade ago.Autoimmune and viral encephalitides can resemble one another and sometimes autoimmune encephalitis may be triggered by viral infections. Early diagnosis and treatment is the key to both causes, which emphasizes the importance of clinical diagnosis before laboratory confirmation.

Objective:Elsberg syndrome (ES) is an established but often unrecognized cause of acute lumbosacral radiculitis with myelitis related to recent herpes virus infection. We defined ES, determined its frequency in patients with cauda equina syndrome (CES) with myelitis, and evaluated its clinical, radiologic, and microbiologic features and outcomes.Methods:We searched the Mayo Clinic medical records for ES and subsequently for combinations of index terms to identify patients with suspected CES and myelitis.Results:Our search yielded 30 patients, 2 diagnosed with ES and an additional 28 with clinical or radiologic evidence of CES retrospectively suspected of having ES. We classified patients in 5 groups according to diagnostic certainty. MRI and EMG confirmed that 2 had only myelitis, 5 only radiculitis, and 16 both. Two had preceding sacral herpes infection and 1 oral herpes simplex. Spinal cord lesions were commonly multiple, discontinuous, not expansile, and centrally or ventrally positioned. Lesions generally spared the distal conus. Nerve root enhancement was occasionally prominent and was smooth rather than nodular. Lymphocytic CSF pleocytosis was common. Thirteen patients (43%) had viral isolation studies, which were commonly delayed; the delay may have accounted for the low rate of viral detection. Acyclovir was administered to 6 patients. Most patients recovered with sequelae; 1 patient experienced encephalomyelitis and died.Conclusion:ES is a definable condition likely responsible for 10% of patients with combined CES and myelitis. Radiologic findings are not entirely specific but may help in differentiating ES from some competing diagnostic considerations. We propose criteria to facilitate diagnosis.

Objective: To characterize patients misdiagnosed with multiple sclerosis (MS). Methods: Neurologists at 4 academic MS centers submitted data on patients determined to have been misdiagnosed with MS. Results: Of 110 misdiagnosed patients, 51 (46%) were classified as “definite” and 59 (54%) “probable” misdiagnoses according to study definitions. Alternate diagnoses included migraine alone or in combination with other diagnoses 24 (22%), fibromyalgia 16 (15%), nonspecific or nonlocalizing neurologic symptoms with abnormal MRI 13 (12%), conversion or psychogenic disorders 12 (11%), and neuromyelitis optica spectrum disorder 7 (6%). Duration of misdiagnosis was 10 years or longer in 36 (33%) and an earlier opportunity to make a correct diagnosis was identified for 79 patients (72%). Seventy-seven (70%) received disease-modifying therapy and 34 (31%) experienced unnecessary morbidity because of misdiagnosis. Four (4%) participated in a research study of an MS therapy. Leading factors contributing to misdiagnosis were consideration of symptoms atypical for demyelinating disease, lack of corroborative objective evidence of a CNS lesion as satisfying criteria for MS attacks, and overreliance on MRI abnormalities in patients with nonspecific neurologic symptoms. Conclusions: Misdiagnosis of MS leads to unnecessary and potentially harmful risks to patients. Misinterpretation and misapplication of MS clinical and radiographic diagnostic criteria are important contemporary contributors to misdiagnosis.

Retroviruses are a family of RNA viruses that replicate by reverse transcription. The family includes HIV and human T-lymphotropic virus. This chapter reviews neurologic manifestations of these retroviruses. A retrovirus in the genus Lentivirus, HIV has 2 forms, HIV-1 and HIV-2. HIV-1 is associated with the global AIDS pandemic, whereas HIV-2 causes an AIDS-like illness primarily in West Africa, although pockets of infection exist globally.

Viruses may cause acute, subacute, or, rarely, chronic infection of the nervous system. The most common acute syndromes of nervous system infections are meningitis and encephalitis, but viruses can also affect the spinal cord and the peripheral nervous system. Viruses can be classified in many ways. One classification scheme assesses the type of nucleic acid (DNA or RNA), whether it is double or single stranded, its sense, and its method of replication.

The diagnostic criteria for multiple sclerosis (MS) rely on clinical, paraclinical, and radiographic findings of limited specificity. Many disorders mimic MS, and the decision of when to investigate an alternative diagnosis can be challenging. Reliance on extensive ancillary testing to exclude potential mimics, however, is unnecessary in most cases. Rather, recognition and rigorous interpretation of "classic" clinical and radiographic features of MS are often sufficient to establish the diagnosis. Misinterpretation of the clinical and radiographic diagnostic criteria for MS in the setting of more common diseases and syndromes and a lack of vigilance for "red flags" are important contributors to misdiagnosis. A clinical framework for the differential diagnosis of MS that emphasizes phenotypes atypical for MS and suggests diseases or syndromes in which they more commonly occur may be an important diagnostic guide for clinicians in contemporary practice.

Objective: To evaluate a trial of immunotherapy as an aid to diagnosis in suspected autoimmune epilepsy. Method: We reviewed the charts of 110 patients seen at our autoimmune neurology clinic with seizures as a chief complaint. Twenty-nine patients met the following inclusion criteria: (1) autoimmune epilepsy suspected based on the presence of ≥1 neural autoantibody (n = 23), personal or family history or physical stigmata of autoimmunity, and frequent or medically intractable seizures; and (2) initiated a 6- to 12-week trial of IV methylprednisolone (IVMP), IV immune globulin (IVIg), or both. Patients were defined as responders if there was a 50% or greater reduction in seizure frequency. Results: Eighteen patients (62%) responded, of whom 10 (34%) became seizure-free; 52% improved with the first agent. Of those receiving a second agent after not responding to the first, 43% improved. A favorable response correlated with shorter interval between symptom onset and treatment initiation (median 9.5 vs 22 months; p = 0.048). Responders included 14/16 (87.5%) patients with antibodies to plasma membrane antigens, 2/6 (33%) patients seropositive for glutamic acid decarboxylase 65 antibodies, and 2/6 (33%) patients without detectable antibodies. Of 13 responders followed for more than 6 months after initiating long-term oral immunosuppression, response was sustained in 11 (85%). Conclusions: These retrospective findings justify consideration of a trial of immunotherapy in patients with suspected autoimmune epilepsy. Classification of evidence: This study provides Class IV evidence that in patients with suspected autoimmune epilepsy, IVMP, IVIg, or both improve seizure control.