Diagnostic reasoning in challenging cases.

Diagnostic reasoning relies on cognitive heuristics to recognise patterns of symptoms and signs in order to arrive at a diagnosis. These rules of thumb allow us to rapidly diagnose common conditions that present in typical ways. However, they may lead us astray when common conditions present atypically or when a patient has a rare condition or multiple conditions causing their constellation of symptoms, signs, and test results, rather than having a single diagnosis to explain them all. This article describes strategies to help counteract diagnostic pitfalls, to expand diagnostic possibilities and to make diagnostic progress with complex, multielement cases.

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.

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.

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.

Neurology Training Worldwide.

Neurology training is essential for providing neurologic care globally. Large disparities in availability of neurology training exist between higher- and lower-income countries. This review explores the worldwide distribution of neurology training programs and trainees, the characteristics of training programs in different parts of the world, and initiatives aimed at increasing access to neurology training in under-resourced regions.

What to do when patients with epilepsy cannot take their usual oral medications.

When people with epilepsy are hospitalised for medical or surgical conditions, they may be unable to take their home antiepileptic drugs (AEDs). Such 'nil by mouth' people with epilepsy require alternative AED regimens to prevent breakthrough seizures. Here, we describe several strategies for maintaining seizure control in patients with epilepsy who have medical or surgical contraindications to their home oral regimens. These strategies include using non-pill oral formulations, using an intravenous formulation of the patient's home AED(s), using a benzodiazepine bridge and/or using alternative intravenous AED(s) when there are no intravenous formulations.

Primary angiitis of the central nervous system: avoiding misdiagnosis and missed diagnosis of a rare disease.

Primary angiitis of the central nervous system (PACNS) is an extremely rare condition, defined as a vasculitis limited to the CNS with no identifiable cause. Its presentation is non-specific and includes headache, cognitive dysfunction and focal neurological signs. Laboratory studies, neuroimaging and angiography are neither sufficiently sensitive nor specific for diagnosis; a definitive diagnosis requires brain biopsy. As a result, PACNS is commonly misdiagnosed. Here, we review its clinical, laboratory and radiological features, and focus on avoiding common diagnostic pitfalls.

The neurology of Sjogren's syndrome and the rheumatology of peripheral neuropathy and myelitis.

Neurological symptoms occur in approximately 20% of patients with Sjögren's syndrome, and may be the presenting manifestations of the disease. Here, we review several neurological conditions that can occur in Sjögren's syndrome: sensory ganglionopathy, painful small fibre neuropathy, and transverse myelitis (independently or as part of neuromyelitis optica). We present the symptoms, signs, differential diagnoses, recommended diagnostic evaluation, and treatment of each of these, highlighting the features that should alert neurologists to consider Sjögren's syndrome.

Development and implementation of a case-based collaborative learning flipped classroom preclinical neurology course.

This paper describes the development, content, structure, and implementation of a case-based collaborative learning, flipped classroom, integrated preclinical neurology, neuroanatomy, and neuroscience course for first year medical students at Harvard Medical School. We report the methods for pre-class preparation, in-class instruction, and evaluation; student feedback with respect to content, teaching method, and learning environment; and several lessons learned regarding how to optimize preparatory and in-class learning in a case-based flipped classroom course.

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.

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.

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.

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.

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.

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.