ISSN:1074-7931    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

BACKGROUND–In myasthenia gravis (MG), the prototypic autoimmune disease, antibodies against acetylcholine receptors impair neuromuscular transmission and produce weakness. Although recognized for several hundred years, it has only been over the last three decades that effective treatments have become available for MG.REVIEW SUMMARY–This review summarizes the principles of normal neuromuscular transmission, the clinical features of MG, and the tests available for its diagnosis. The current treatments for MG are discussed, including possible mechanisms of action and a discussion of potential adverse effects. When available, evidence-based justification for individual treatment options is given, and areas of controversy identified.CONCLUSIONS–Significant improvements in the diagnosis and management of MG have been made over the last several decades. The available treatments either improve neuromuscular transmission directly, or suppress or modulate the pathogenic immune response in MG. Treatment is highly individualized and must take into account the severity of disease, the presence of other diseases, and the kinetics of response for the available treatments. This requires detailed knowledge of the mechanisms of action and possible adverse effects for each treatment. However, despite an optimistic outlook with modern treatment, the management of MG continues to be plagued by lack of efficacy in some, and significant adverse effects in most MG patients.

ISSN:1074-7931    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

BACKGROUND–Hypertensive encephalopathy (HTE) is a syndrome typified by headache, seizures, and neurologic signs associated with increased systemic blood pressures; edema in the subcortical white matter is seen on imaging studies and is usually reversible, although infarction or hemorrhage may supervene. Based on previous work, we theorize that HTE is associated with increased perfusion to the brain. Syndromes related to HTE may also be encountered in clinical situations in which perfusion to the brain is acutely increased without systemic hypertension (i.e., after treatment of high-grade carotid stenoses or large intracranial arteriovenous malformations, or in high altitude mountain sickness). We therefore refer to these conditions more generally as hyperperfusion encephalopathies (HPE).REVIEW SUMMARY–The clinical and radiographic data of 110 patients (average age, 50.1 years) who presented at the Brigham and Women’s Hospital with clinical and radiographic signs of HPE were reviewed; 104 had systemic hypertension and 6 had postcarotid endarterectomy hyperperfusion syndrome. Edema involved the subcortical white matter and occasionally the cortex in all patients. In patients with systemic hypertension, the edema was usually bilateral and located predominantly in the occipital lobes; other brain regions included the parietal lobes, posterior frontal lobes, cerebellum, and splenium of the corpus callosum. The six patients with postcarotid endarterectomy hyperperfusion syndrome had edema in the hemisphere ipsilateral to the operated side involving the anterior and middle cerebral artery territories. The edema in HPE was associated with: increased low attenuation on CT; decreased T1and increased T2signal on MR imaging; increased cerebral perfusion on single emission computed tomography (SPECT) and perfusion MR imaging; and did not show restricted diffusion on MR imaging. The syndrome resolved completely in most cases after the administration of antihypertensive agents, although rarely small infarcts and hemorrhages occurred. Three patients with thrombocytopenia developed large fatal intracranial hemorrhages.CONCLUSION–The symptoms of HPE are usually nonspecific, but the radiographic findings are consistent. Treatment should be instituted rapidly and patients should be followed until the condition resolves either clinically or radiographically; hemorrhagic complications, although rare, can be serious.

ISSN:1074-7931    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

BACKGROUND–Neurosurgical clipping used to be the standard method of occluding intracranial aneurysms, but controlled detachable coils are increasingly used to obliterate aneurysms by endosaccular packing.REVIEW SUMMARY–A systematic review of observational studies on embolization with coils showed in patients with a ruptured aneurysm a complete occlusion in 52% of aneurysms, independence at follow-up in 89% of patients, and a procedure related mortality of 1.1%. There is no consensus with regard to the indications for surgical or endovascular treatment. A recently published randomized trial on early coiling versus early operation did not show any differences in clinical outcome after 3 and 12 months, but the small number of patients included precludes firm conclusions. Comparisons between endovascular and surgical treatment should not only address safety and clinical outcome, but also the long-term angiographic results and the risk of recurrent hemorrhage after treatment. In current practice, many patients with a basilar bifurcation aneurysm are treated by embolization with coils. In many patients with a middle cerebral artery aneurysm operation is the preferred treatment. For all other aneurysm locations preference for coiling or clipping depends on the clinical condition of the patient, the configuration of the aneurysm, and on the experience and skills of the local endovascular and neurosurgical team.CONCLUSIONS–Endovascular treatment of intracranial aneurysms has gained widespread acceptance. Preference for coiling or clipping depends on patient and aneurysm characteristics, and on the local expertise.

ISSN:1074-7931    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

BACKGROUND–Ectopic impulses in motor nerves generate clinically and electromyographically detectable activity in muscle. These discharges occur in the form of isolated fasciculations, as persistent muscle activity in the form of myokymia and neuromyotonia, or in fulminant contractions of individual muscles in the form of a cramp. In the last 20 years, new studies have helped establish the relationship of fasciculations with cramps and neuromyotonia and have identified common pathophysiologic mechanisms.REVIEW SUMMARY–Current evidence suggests that both cramps and fasciculations originate primarily in the most distal motor nerve terminals. In this portion of the axon, the overlying Schwann cells do not form a myelin sheath and the blood-nerve barrier is relatively porous. The terminal axon is studded with receptors to monitor the release of neurotransmitters. Under certain stresses, reinnervation, ionic imbalances, motor nerve disease, or pharmacologic challenge, ectopic impulses arise and create visible, but sporadic fasciculations. Other circumstances, including muscle shortening and dehydration, give rise to more frequent and localized fasciculations that can erupt into a painful muscle cramp. The most unusual motor ectopic phenomena involves rapidly recurrent discharges in multiple motor nerves, giving rise to grouped fasciculations, including myokymia and neuromyotonia. Recent studies have implicated toxins, and autoimmune and genetic mechanisms in the generation of neuromyotonic and myokymic syndromes. Plasma exchange, carbamazepine, and phenytoin have proven helpful in select cases.CONCLUSION–These findings indicate that motor nerve hyperexcitability is a fruitful subject of clinical and laboratory investigation and that treatment based on underlying mechanisms proves beneficial.

ISSN:1074-7931    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

BACKGROUND–To correlate the serum tumor necrosis factor-&agr; (TNF&agr;) concentrations before, during and following plasma exchange in patients with Guillain-Barré syndrome (GBS). In this prospective study, 21 GBS patients were selected. Patients in clinical stages III to V were subjected to plasma exchange. The control group included equal numbers of age-matched patients with other neurological diseases and healthy voluntary blood donors. A sandwich ELISA method was applied to estimate serum TNF&agr; concentrations in test and control groups.REVIEW SUMMARY–Twelve GBS patients had elevated serum TNF&agr; levels that ranged between 74 and 182 pg/mL. All 12 GBS patients showed a steady decrease in the TNF&agr; concentration following plasma exchange and also showed a positive correlation with neurological recovery.CONCLUSIONS–We conclude that serum TNF&agr; concentrations are elevated in 57.1% of GBS patients and TNF&agr; level decreases following plasma exchange.

ISSN:1074-7931    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:1074-7931    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:1074-7931    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:1074-7931    

出版商:OVID    

年代:2002

数据来源: OVID