Handbook of clinical neurology最新文献

Neuroendocrine neoplasms (NENs) are a heterogeneous group of tumors arising from the transformation of neuroendocrine cells in several organs, most notably the gastro-entero-pancreatic system and respiratory tract. The classification was recently revised in the 5th Edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. NENs can rarely spread to the central or peripheral nervous systems. Neurologic involvement is determined by the rare development of paraneoplastic syndromes, which are remote effects of cancer. Mechanisms depend on immunologic response to a tumor, leading to the immune attack on the nervous system or the production of biologically active ("functioning") substances, which can determine humoral (endocrine) effects with neurologic manifestations. Paraneoplastic neurologic syndromes (PNS) are immunologically mediated and frequently detected in small cell lung cancer but rarely seen in other forms of NEN. PNS and Merkel cell carcinoma is increasingly reported, especially with Lambert Eaton myasthenic syndrome. Endocrine manifestations are found in a wide spectrum of NENs. They can develop at any stage of the diseases and determine neurologic manifestations. Patient outcomes are influenced by tumor prognosis, neurologic complications, and the severity of endocrine effects.

Meralgia paresthetica is a common but probably underrecognized syndrome caused by dysfunction of the lateral femoral cutaneous nerve. The diagnosis is based on the patient's description of sensory disturbance, often painful, on the anterolateral aspect of the thigh, with normal strength and reflexes. Sensory nerve conduction studies and somatosensory evoked potentials may be used to support the diagnosis, but both have technical limitations, with low specificity and sensitivity. Risk factors for meralgia paresthetica include obesity, tight clothing, and diabetes mellitus. Some cases are complications of hip or lumbar spine surgery. Most cases are self-limited, but a small proportion of patients remain with refractory and disabling symptoms. Treatment options include medications for neuropathic pain, neurolysis, neurectomy, and radioablation, but controlled trials to compare efficacy are lacking.

Menstrually related migraine is a disabling condition affecting 35% to 54% females with migraine during their fertile years. The International Headache Classification distinguishes menstrually related migraine from pure menstrual migraine based on the occurrence of the attacks even outside the perimenstrual periods. Hormonal fluctuations are the main driver for the disease in subjects with genetic susceptibility and alterations of brain structures and connectivity. Menstrually related attacks are often particularly severe and disabling requiring proper management. Acute treatment mainly consists of nonsteroidal anti-inflammatory drugs (NSAIDs), recommended in patients also suffering from dysmenorrhea, and triptans. Prevention is specifically indicated in women with high monthly headache frequency or burdensome attacks during perimenstrual periods. Trials proved the efficacy of short-term prevention with triptans and NSAIDs but did not evaluate possible long-term effectiveness and tolerability. Evidence of prevention using hormonal treatments is poor, but extended-cycle treatments might be suitable for women requiring hormonal replacement for concomitant conditions. Few data are available on treatments targeting CGRP, among whom gepants are the most promising because of their utility both in migraine acute and preventive treatment. A greater recognition of disease and a deep knowledge of patients' comorbidities are essential to its proper management.

Autologous hematopoietic stem cell transplantation (AHSCT) is a therapeutic procedure for autoimmune diseases which suppresses inflammation and resets the immune system, thereby halting disease activity and disability progression in treatment-resistant patients. This chapter reviews existing guidelines and health economic evaluations of AHSCT for multiple sclerosis (MS) and presents a cost-utility analysis from the UK NHS and personal social services perspective comparing AHSCT with disease-modifying therapies (DMTs) in patients with highly active relapsing-remitting MS (RRMS) based on the only published randomized controlled trial, "MIST," in this population. Over a 5-year time horizon, AHSCT was dominant (more effective and less costly) over the DMTs in MIST. At a threshold of £20,000 per QALY, there was a 100% probability that AHSCT was cost-effective. This result is explained by the high ongoing costs of DMTs compared with the up-front cost of AHSCT, combined with the high effectiveness of AHSCT. When compared with natalizumab, the result did not change; AHSCT remained dominant. These results support current guideline recommendations regarding AHSCT for highly active RRMS. The cost-effectiveness of AHSCT in progressive and aggressive MS and other immune-mediated neurologic diseases remains uncertain due to a lack of health economic analyses, reflecting the limited clinical evidence base.

The development of autoimmune diseases (ADs) is thought to be caused by a dysfunction of the intrinsic ability of our immune system for "self-nonself" discrimination. Following the breakdown of "self-tolerance," an orchestrated immune cascade develops, involving B- and T-lymphocytes and autoantibodies that target self-antigens. An imbalance of the regulatory immune network and a suitable genetic background, along with external (infectious and environmental) triggers, are all important contributors to the outbreak of clinical autoimmunity. Immunotherapies for ADs can be classified into treatments that are given continuously (chronic treatments) and therapies that are applied only once or intermittently, aiming to induce partial or complete reconstitution of the immune system [immune reconstitution therapies (IRTs)]. The principle underlying IRTs is based on the depletion of mature immune cells and the rebuilding of the immune system. During this process of immune reconstitution, a substantial change in the lymphocyte repertoire occurs, which may explain the impressive and long-term beneficial effects of IRTs, including the possibility of induction of tolerance to self-antigens. Hematopoietic (or bone marrow) stem cell transplantation (HSCT or BMT) represents the prototype-and the most radical type-of IRT therapy. The rationale for HSCT or BMT for the treatment of severe ADs is based on convincing proof in preclinical studies, utilizing various animal models of autoimmunity. More than 30 years' worth of pioneering experiments in various models of ADs have shown that HSCT can lead to substantial improvement or even cure of the autoimmune syndromes and induction of long-term tolerance to autoantigens. The success of treatment depends on how completely the autoantigen-reactive lymphocytes and memory cells are eradicated by the conditioning chemotherapy, which is administered in a single dose before the transplantation. The most successful conditioning methods in animal models of ADs are total body irradiation (TBI) and high-dose cyclophosphamide (CY). These preclinical studies, summarized in this review, have provided important data about the therapeutic potential of HSCT in human ADs and the associated mechanisms of action and have contributed to the formulation of guidelines for clinical applications of autologous or allogeneic HSCT/BMT in refractory autoimmunity.

Most hematopoietic stem cell transplants performed for an autoimmune disease of the nervous system, use the patient's hematopoietic stem cells (HSCs). Obtaining an HSC graft is the first step of the process. This typically involves mobilization of bone marrow HSCs into the circulation using high-dose cyclophosphamide followed by filgrastim, a drug based on granulocyte colony-stimulating factor. Toxicity from these agents is usually manageable and adverse events are less severe and less frequent than those experienced during the hematopoietic stem cell transplant. Following mobilization, HSCs are collected from the circulation by leukapheresis. Some centers deplete the graft of lymphocytes using an ex vivo immunomagnetic selection procedure. HSC grafts are cryopreserved until required for the stem cell transplant. Quality testing of the graft ensures sterility and it contains sufficient HSCs and hematopoietic progenitors. The clinical and laboratory aspects of HSC graft mobilization, collection, and storage must meet standards set by national regulatory bodies and accredited by international professional standards organizations. Experienced stem cell transplant teams are important for minimizing procedural toxicity and enhancing successful collection.

Medication overuse headache (MOH) is a secondary headache characterized by frequent use of acute or symptomatic migraine medications at a sufficient frequency to transform patients from episodic to chronic migraine. MOH represents a significant medical problem, with a serious burden on patients' lives and on society as a whole. MOH patients often have additional comorbidities, and the clinical challenge of helping patients reduce acute medication use and revert to episodic headache can be marked. Treatment includes education and prevention; withdrawal programs; pharmacological prophylaxis; multidisciplinary therapies with behavioral and noninvasive neuromodulation options; and scheduled, frequent follow-up to prevent relapses. The advent of anti-CGRP therapy monoclonal antibodies may provide an alternative to more extensive programs for less complex patients. This review also provides guidance for which patients may benefit most from coordinated integrated programs.

In neurology practice, it is common to encounter a variety of visual complaints. Historically, in the absence of known ocular pathology, epilepsy, or insult to the central nervous system, positive symptoms were assumed to be migrainous in origin. This assumption was sometimes made even in the absence of a history of migraine. In the past decade, there has been considerable effort to better delineate and study nonmigrainous visual phenomena, with the most extensive focus on a newly defined syndrome, visual snow syndrome (VSS). The heightened awareness of visual snow as a symptom and syndrome has greatly enhanced the understanding of this visual phenomenon; however, in the last few years, there has been an almost pendulous swing in clinic, with patients now being given the diagnosis of VSS for any dots or flickering they may have in their vision. To avoid clinical misdiagnosis, it is critical that we expand our understanding not just of VSS but also of underlying pathologies that may present similarly. This chapter will review classical migraine aura, persistent migraine aura, visual snow and a number of positive and negative visual complaints that are on the differential when seeing patients with suspected aura or visual snow. This is followed by an in-depth discussion on the current understanding of the presenting symptoms, pathophysiology, evaluation and management of VSS. We also outline secondary causes of visual snow.

Migraine is commonly comorbid with psychiatric conditions, particularly major depressive disorder, anxiety disorders, and sleep disorders. The presence of psychiatric disorders can make diagnosis and treatment more challenging. Existing studies suggest that the relationship between migraine and psychiatric disorders is bidirectional, such that each disorder confers increased risk for onset of the other. Mechanisms underlying this comorbidity are largely speculative but include serotonergic dysfunction, medication overuse, allostatic load, and behavioral factors such as pain-related appraisals and unwarranted avoidance behaviors. Psychiatric comorbidities present unique clinical considerations for assessment and treatment, foremost among which is a need to routinely screen migraine patients for depression, anxiety, and insomnia. Common screening considerations and measures validated on headache patients are reviewed. Comprehensive treatment of migraine requires interventional attention also to any psychiatric comorbidities, though few randomized trials have rigorously evaluated the efficacy of pharmacologic or behavioral migraine interventions for comorbid psychiatric symptoms. Most modern antidepressants lack strong efficacy for migraine, and providers often utilize separate agents to treat migraine and any psychiatric comorbidities. Recent research on adjunctive behavioral interventions such as cognitive-behavioral therapy and acceptance-based approaches suggests they hold value in reducing psychiatric symptoms, though larger trials are needed.

The sciatic nerve is the body's largest peripheral nerve. Along with their two terminal divisions (tibial and fibular), their anatomic location makes them particularly vulnerable to trauma and iatrogenic injuries. A thorough understanding of the functional anatomy is required to adequately localize lesions in this lengthy neural pathway. Proximal disorders of the nerve can be challenging to precisely localize among a range of possibilities including lumbosacral pathology, radiculopathy, or piriformis syndrome. A correct diagnosis is based upon a thorough history and physical examination, which will then appropriately direct adjunctive investigations such as imaging and electrodiagnostic testing. Disorders of the sciatic nerve and its terminal branches are disabling for patients, and expert assessment by rehabilitation professionals is important in limiting their impact. Applying techniques established in the upper extremity, surgical reconstruction of lower extremity nerve dysfunction is rapidly improving and evolving. These new techniques, such as nerve transfers, require electrodiagnostic assessment of both the injured nerve(s) as well as healthy, potential donor nerves as part of a complete neurophysiological examination.