Metabolic and Toxic Myelopathies.

OBJECTIVE: This article reviews the clinical presentation, diagnostic evaluation, and treatment of metabolic and toxic myelopathies resulting from nutritional deficiencies, environmental and dietary toxins, drugs of abuse, systemic medical illnesses, and oncologic treatments. LATEST DEVELOPMENTS: Increased use of bariatric surgery for obesity has led to higher incidences of deficiencies in nutrients such as vitamin B12 and copper, which can cause subacute combined degeneration. Myelopathies secondary to dietary toxins including konzo and lathyrism are likely to become more prevalent in the setting of climate change leading to drought and flooding. Although modern advances in radiation therapy techniques have reduced the incidence of radiation myelopathy, patients with cancer are living longer due to improved treatments and may require reirradiation that can increase the risk of this condition. Immune checkpoint inhibitors are increasingly used for the treatment of cancer and are associated with a wide variety of immune-mediated neurologic syndromes including myelitis. ESSENTIAL POINTS: Metabolic and toxic causes should be considered in the diagnosis of myelopathy in patients with particular clinical syndromes, risk factors, and neuroimaging findings. Some of these conditions may be reversible if identified and treated early, requiring careful history, examination, and laboratory and radiologic evaluation for prompt diagnosis.

Clinical Features and Diagnosis of Intramedullary Spinal Cord Abscess in Adults: A Systematic Review.

BACKGROUND AND OBJECTIVES: Intramedullary spinal cord abscess (ISCA) was described 200 years ago but remains poorly understood and is often mistaken for immune-mediated or neoplastic processes. We present a systematic review of ISCA in adults, describing the clinical presentation, diagnostic features, treatment strategies, and outcomes. METHODS: Database searches for intramedullary abscess were performed on April 15, 2019, and repeated on February 9, 2022, using PubMed and EMBASE with 2 unpublished cases also included. Publications were independently reviewed for inclusion by 2 authors followed by adjudication. Data were abstracted using an online form and then analyzed for predictors of disability. RESULTS: A total of 202 cases were included (median age 45 years [interquartile range 31-58]; 70% male). Thirty-one percent of those affected had no identified predisposing condition. The most common symptom was weakness (97%), and the median symptom duration before presentation was 10 days (interquartile range 5-42). An MRI showed restricted diffusion in 100% of 8 cases where performed and enhancement in 99% of 153 cases where performed. The most common organisms were Mycobacterium tuberculosis (29%), Streptococcus sp. (13%), and Staphylococcus sp. (10%). All patients received antimicrobial therapy; surgical drainage was performed in 65%. At follow-up (median 6 months), 12% had died, 69% were ambulatory, and 77% had improved compared with clinical nadir. Of those who underwent operative intervention, surgery within 24 hours of diagnosis was associated with an increased likelihood of being ambulatory at follow-up compared with surgery after 24 hours (odds ratio 4.44; 95% CI 1.26-15.61; p = 0.020). DISCUSSION: ISCA is important to consider in any patient presenting with acute-to-subacute, progressive myelopathy. Immunocompromise and typical signs of infection (e.g., fever) are often absent. Diffusion restriction and gadolinium enhancement on MRI seem to be sensitive. Antimicrobial therapy with surgical drainage is the most common therapeutic approach, but morbidity remains substantial. If performed, urgent surgery may be more beneficial.

The case of a 49-year-old man with involuntary toe movements.

A 49-year-old man presented with 3 years of leg pain and involuntary toe movements. He described the pain as mild burning, radiating from the left foot upward to the leg. On examination, there were involuntary continuous flexion-extension movements of his left toes (video). Strength, sensation, and reflexes were normal. Lumbosacral MRI demonstrated diffuse degenerative disc disease with multi-level mild-to-moderate foraminal stenosis. Nerve conduction studies were normal. EMG showed neurogenic potentials and active denervation changes in the left anterior tibial and soleus muscles consistent with radiculopathy. The diagnosis of painful legs and moving toes is discussed.

Historical Perspectives on the Neurologic Manifestations of Viral Pandemics.

Neurologic symptoms have been reported in over 30% of hospitalized patients with coronavirus disease 2019 (COVID-19), but the pathogenesis of these symptoms remains under investigation. Here, we place the neurologic complications of COVID-19 within the context of three historical viral pandemics that have been associated with neurologic diseases: (1) the 1918 influenza pandemic, subsequent spread of encephalitis lethargica, and lessons for the study of COVID-19-related neuroinflammation; (2) the controversial link between the 1976 influenza vaccination campaign and Guillain-Barré Syndrome and its implications for the post- and parainfectious complications of COVID-19 and COVID-19 vaccination; and (3) potential applications of scientific techniques developed in the wake of the human immunodeficiency virus pandemic to the study of postacute sequelae of COVID-19.

Consensus Competencies for Postgraduate Fellowship Training in Global Neurology.

BACKGROUND AND OBJECTIVES: Use a modified Delphi approach to develop competencies for neurologists completing ≥1 year of advanced global neurology training. METHODS: An expert panel of 19 United States-based neurologists involved in global health was recruited from the American Academy of Neurology Global Health Section and the American Neurological Association International Outreach Committee. An extensive list of global health competencies was generated from review of global health curricula and adapted for global neurology training. Using a modified Delphi method, United States-based neurologists participated in 3 rounds of voting on a survey with potential competencies rated on a 4-point Likert scale. A final group discussion was held to reach consensus. Proposed competencies were then subjected to a formal review from a group of 7 neurologists from low- and middle-income countries (LMICs) with experience working with neurology trainees from high-income countries (HICs) who commented on potential gaps, feasibility, and local implementation challenges of the proposed competencies. This feedback was used to modify and finalize competencies. RESULTS: Three rounds of surveys, a conference call with United States-based experts, and a semistructured questionnaire and focus group discussion with LMIC experts were used to discuss and reach consensus on the final competencies. This resulted in a competency framework consisting of 47 competencies across 8 domains: (1) cultural context, social determinants of health and access to care; (2) clinical and teaching skills and neurologic medical knowledge; (3) team-based practice; (4) developing global neurology partnerships; (5) ethics; (6) approach to clinical care; (7) community neurologic health; (8) health care systems and multinational health care organizations. DISCUSSION: These proposed competencies can serve as a foundation on which future global neurology training programs can be built and trainees evaluated. It may also serve as a model for global health training programs in other medical specialties as well as a framework to expand the number of neurologists from HICs trained in global neurology.

A 47-Year-Old Man Presenting With Seizures and Prior Stroke.

A 47-year-old man presented to his local hospital in Peru after a generalized tonic-clonic seizure. His family reported a history of prior stroke of unclear etiology. This case report discusses the approach to a first seizure (including in tropical regions like Peru), the relationship between stroke and seizures, the approach to stroke in the young, and how to diagnose rare diseases in resource-limited settings.

Engaging teaching strategies in neurology: the flipped classroom and simulation training.

Just as neurology continues to expand its diagnostic and therapeutic modalities, so too does neurology education continue to expand in its pedagogical modalities. In this article, we describe two educational techniques-the flipped classroom and simulation-that we have incorporated in our teaching of neurology to students and doctors in training, with some practical tips for their successful implementation.

Clinical Problem-Solving: 72-Year-Old Woman With Multifocal Strokes and an Intracardiac Mass.

We present the case of a 72-year-old female with multifocal strokes found to have multiple, mobile intracardiac masses. We discuss the differential diagnosis and evaluation of intracardiac masses, and the challenges in management of the ultimately diagnosed etiology of stroke in this patient.

Approach to Neurologic Infections.

PURPOSE OF REVIEW: This article provides an overview of the clinical approach to the diagnosis of neurologic infections, focusing on the symptoms, signs, imaging features, and laboratory findings of the major categories of neuroinfectious diseases. RECENT FINDINGS: The increased use of immunosuppressive and immunomodulatory therapy to treat autoimmune diseases has led to an increase in opportunistic neurologic infections. The description of numerous causes of autoimmune antibody-mediated encephalitis over the past decade has expanded the differential diagnosis of encephalitis beyond infection. The emergence of metagenomic next-generation sequencing has led to diagnoses of rare or unexpected causes of neurologic infections and has the potential to enhance diagnostic precision in neuroinfectious diseases. SUMMARY: Infections of the nervous system can affect any level of the neuraxis and present over any time course. Neurologic infections may present atypically with respect to clinical, radiologic, and CSF analysis features in immunocompromised patients or older adults. A thorough evaluation including systemic features, past medical history, travel, exposures, detailed examination, neuroimaging, and CSF analysis is often necessary to make a definitive diagnosis. It is important to be aware of the test characteristics and limitations of microbiological tests on CSF for neurologic infections to avoid being misled by false positives or false negatives.

Meningitis.

PURPOSE OF REVIEW: This article reviews the diagnosis and treatment of infectious meningitis, including updates on newer molecular diagnostic techniques for microbiological diagnosis. RECENT FINDINGS: New polymerase chain reaction (PCR)-based molecular diagnostic techniques have improved the timeliness of microbiological diagnosis in meningitis, but clinicians must be aware of the limitations of such tests. Next-generation sequencing can now be applied to CSF, allowing for diagnosis of infections not identifiable by conventional means. SUMMARY: Infectious meningitis can be caused by a broad range of organisms. The clinician must be aware of the test characteristics of new molecular techniques for microbiological diagnosis as well as traditional techniques to tailor antimicrobial therapy appropriately in patients with meningitis.

Beyond electives: Rethinking training in global neurology.

Global health electives in neurology residencies provide opportunities for high-income country trainees, but have limited benefits-and may create burdens-for lower-income country hosts. Current suspension of global health electives for U.S. neurology residents due to the COVID-19 pandemic provides an opportunity to reflect on ways to reimagine global health education during this period and beyond. The framework proposed in this article underscores the need for equitable, bidirectional international partnerships and highlights global health educational innovations developed during the pandemic.

Clinical-Radiologic Dissociation in Post-traumatic Syringomyelia.

Post-traumatic syringomyelia develops years to decades after spinal trauma in up to 28% of patients. We report a case of a man who developed extensive syringomyelia 14 years after spinal trauma, but had only minimal symptoms. Presumed pathophysiology of this condition and options for surgical management are briefly reviewed.

Metabolic and Toxic Myelopathies.

Metabolic and toxic causes of myelopathy form a heterogeneous group of disorders. In this review, we discuss the causes of metabolic and toxic myelopathies with respect to clinical presentation, pathophysiology, diagnostic testing, treatment, and prognosis. This review is organized by temporal course (hyperacute, acute, subacute, and chronic) and etiology (e.g., nutritional deficiency, toxic exposure). Broadly, the myelopathies associated with dietary toxins (neurolathyrism, konzo) and decompression sickness present suddenly (hyperacute). The myelopathies associated with heroin use and electrical injury present over hours to days (acutely). Most nutritional deficiencies (cobalamin, folate, copper) and toxic substances (nitrous oxide, zinc, organophosphates, clioquinol) cause a myelopathy of subacute onset. Vitamin E deficiency and hepatic myelopathy cause a chronic myelopathy. Radiation- and intrathecal chemotherapy-induced myelopathy can cause a transient and/or a progressive syndrome. For many metabolic and toxic causes of myelopathy, clinical deficits may stabilize or improve with rapid identification and treatment. Familiarity with these disorders is therefore essential.

Protocolized emergency department observation care improves quality of ischemic stroke care in Haiti.

INTRODUCTION: In many low-income countries, Emergency Medicine is underdeveloped and faces many operational challenges including emergency department (ED) overcrowding and prolonged patient length of stays (LOS). In high-resource settings, protocolized ED observation unit (EDOU) care reduces LOS while preserving care quality. EDOUs are untested in low-income countries. We evaluate the effect protocolized EDOU care for ischemic stroke on the quality and efficiency of care in Haiti. METHODS: We performed a prospective cohort study of protocolized observation care for ischemic stroke at a Haitian academic hospital between January 2014 and September 2015. We compared patients cared for in the EDOU using the ischemic stroke protocol (study group) to eligible patients cared for before protocol implementation (baseline group), as well as to eligible patients treated after protocol introduction but managed without the EDOU protocol (contemporary reference group). We analysed three quality of care measures: aspirin administration, physical therapy consultation, and swallow evaluation. We also analysed ED and hospital LOS as measures of efficiency. RESULTS: Patients receiving protocolized EDOU care achieved higher care quality compared to the baseline group, with higher rates of aspirin administration (91% v. 17%, p < 0.001), physical therapy consultation (50% v. 9.6%, p < 0.001), and swallow evaluation (36% v. 3.7%, p < 0.001). We observed similar improvements in the study group compared to the contemporary reference group. Most patients (92%) were managed entirely in the ED or EDOU. LOS for non-admitted patients was longer in the study group than the baseline group (28 v. 19 h, p = 0.023). CONCLUSION: Protocolized EDOU care for patients with ischemic stroke in Haiti improved performance on key quality measures but increased LOS, likely due to more interventions. Future studies should examine the aspects of EDOU care are most effective at promoting higher care quality, and if similar results are achievable in patients with other conditions.

A Clinical Approach to Diagnosing Encephalopathy.

Encephalopathy refers to dysfunction of the level or contents of consciousness due to brain dysfunction and can result from global brain insults or focal lesions. The underlying causes of encephalopathy include both primary neurologic and systemic conditions. This article discusses the differential diagnosis of encephalopathy, with a focus on primary neurologic causes. A practical schema for organizing the differential diagnosis is to group etiologies by their pace of onset and evolution (eg, sudden, acute, subacute, chronic).