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Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune neuromuscular disorder affecting the presynaptic neuromuscular junction. LEMS is considered to be a rare disease, but its clinical recognition and diagnosis are important due to its high association with underlying lung cancer which may be detected at the very early stages. The onset is insidious and its clinical features are subtle which add to the further delay of diagnosis, between months to years., (Copyright (c) 2009 S. Karger AG, Basel.)

The inflammatory myopathies are a heterogeneous group of immune-mediated myopathies that present as pure form or in association with other autoimmune diseases or malignancy. Although they share few similarities in their clinical presentations and pathophysiologic aspects, for the most part they are different and distinctive. The 3 major subsets are: dermatomyositis (DM), polymyositis (PM), and sporadic inclusion body myositis (S-IBM).This review highlights our understanding of these disorders, their clinical aspects, diagnosis, pathogenesis, and treatment.

Background: Behçet disease is a vasculitis with mucocutaneous, ocular, arthritic, vascular, and other manifestations. Its neurologic manifestations (neuro-Behçet disease) are relatively rare, but they must be thoroughly investigated due to their grave prognosis., Review Summary: The frequency of neurologic manifestations, more common in male Behçet patients, is between 5% and 30%. Both the central and peripheral nervous systems can be involved. Central nervous system manifestations can be divided into 2 main groups: (1) parenchymal involvement, which includes brainstem involvement, hemispheric manifestations, spinal cord lesions, and meningoencephalitic presentations; (2) nonparenchymal involvement, including dural sinus thrombosis, arterial occlusion, and/or aneurysms. Peripheral neuropathy and myopathy are relatively rare. Cerebrospinal fluid analysis reveals pleocytosis and elevated protein levels. Magnetic resonance imaging is the investigation of choice which often reveals iso-/hypointense lesions in T1-weighted images and hyperintense lesions in T2-weighted images, mostly in the mesodiencephalic junction, cerebellar peduncles, and other parts of the brainstem. Corticosteroids and adjuvant immunosuppressive therapy are used for parenchymal manifestations, and corticosteroids and anticoagulants are used for treatment of dural sinus thrombosis., Conclusion: Neuro-Behçet disease must be considered in the differential diagnosis of stroke in young adults, multiple sclerosis, movement disorders, intracranial hypertension, intracranial sinovenous occlusive diseases, and other neurologic syndromes.

Recent advances in neuroimmunology have led to improvements in the pathogenesis, diagnosis, prognosis, and treatment of many neuromuscular disorders. The value of autoantibody testing is increasing steadily in neurologic practice. Not all antibodies have a high yield in diagnosis. In some disorders, such as generalized adult onset of myasthenia gravis, Lambert-Eaton myasthenic syndrome,Miller Fisher syndrome, and multifocal motor neuropathy,autoantibody tests provide accurate diagnosis and can be considered biologic markers of these disorders.

Stretch of nerve has been reported to decrease the amplitude of the compound action potential (CAP) with a complete block appearing in approximately 30 minutes. But for the most part, those experiments were carried out in vivo, and it is generally accepted that the failure of responses was due to a closure of vessels supplying the nerve with a resulting ischemia and anoxia. These studies were undertaken to determine if stretch of nerve has effects that are independent of interference with its vascular supply. In the studies, lengths of rat sciatic and dog peroneal nerves were removed and placed in a chamber supplied with oxygen in which their CAPs were continuously elicited and recorded. This in vitro preparation obviated interference with the nerve's metabolism on stretching. We have previously shown that the form change termed 'beading,' appearing within 10 seconds and reversing as quickly on relaxation, can be elicited with tensions of only several grams. We wished to determine if stretch adequate to produce beading could alter CAPs with the same rapidity. Tensions below 2 g had little effect. On applying tensions of 10-100 g, levels well above those needed to bead the fibers, both increases and decreases of CAP amplitude were seen. The changes occurred within 10 seconds of stretch application, the time at which beading arises with stretch. Although the decreases of CAP amplitudes could be accounted for by beading, the degree of CAP change did not correspond to the amount of tension applied. We hypothesize that the constrictions in the beaded fibers increase axial resistivity and diminish local currents so as to block conduction. The lack of an increasing degree of decreased CAP amplitude with increases in tension is ascribed to the inhibition of elongation offered by the collagen fibrils present in nerve. Collagenase applied to nerves allowed a further increase in length, producing a 'hyperbeading,' showing much longer lengths of beading constrictions on stretch. This would further increase axial resistance and is taken to account for the greater decreases of CAP amplitudes seen following collagenase treatment. To account for those cases where increases of CAP amplitude were seen on stretch, we hypothesize that stretch can also cause an increase in the excitability of the nodes. The outcome of stretch in any given nerve would be the resultant of two opposing actions; beading of the internodes causes a decrease of local currents leading to block of CAPs, while an increased excitability of the nodes acts to augment the responses.

This article briefly reviews the initial approach to the patient suspected of having metabolic myopathy. Diagnostic highlights include relevant points of history, physical examination, blood work-up, forearm ischemic exercise test, electrophysiologic testings and muscle biopsy. The diagnostic evaluation is discussed in detail in separate articles.

This article provides a review of some of the muscular disorders that can arise from some of the commonly seen endocrinologic disturbances. Thyroid, parathyroid, and adrenal dysfunctions as they relate to neuromuscular symptoms are discussed. Common clinical presentations of the endocrine myopathies are highlighted, along with diagnostic evaluation and treatments.

Domiciliary assisted ventilation has been used to prolong life in patients with neuromuscular diseases. Although earlier studies suggest that the majority of patients are satisfied with their lives, the physician's perception of a patient's poor quality of life on assisted ventilation is a major reason for discouraging assisted ventilation. In this study, the quality of life was assessed in 19 patients with neuromuscular diseases on domiciliary tracheal intermittent positive-pressure ventilation for a mean duration of 54 months. An attempt was made to compare the quality of life of Duchenne muscular dystrophy patients with that of amyotrophic lateral sclerosis patients. More than two-thirds of patients were satisfied with their lives. Eighty-four percent thought they had made the right choice. Patients with amyotrophic lateral sclerosis were somewhat more negative or ambiguous toward assisted ventilation and had lower life satisfaction scores as compared with Duchenne muscular dystrophy patients. Financial stresses were significant. Assisted ventilation should be offered as a viable option to patients with neuromuscular diseases. Larger studies may be useful in influencing insurance companies to make expenses associated with assisted ventilation reimbursable.

The most common form of diabetic neuropathy is chronic, distal symmetrical sensorimotor, or predominantly sensory neuropathy; the latter is invariably associated with some degree of autonomic dysfunction. There are, however, other neuropathic patterns in diabetes mellitus that are uncommon but are important to recognize, since they may mimic many other non-neurologic diseases. This article discusses a variety of forms of mononeuropathies and diabetic proximal motor neuropathy, commonly known as diabetic amyotropy.

Toxic myopathies may occur with a variety of prescribed medications, illicit drug abuse, or other toxins. The article discusses an overview of some of the compounds that may cause myopathy, the clinical and laboratory features, histology, mechanisms of action, and potential risk factors of myopathy. The ability to recognize these syndromes is essential to avoid unnecessary tests and to avoid delay in treatment, especially in critically ill patients or patients with other neuromuscular diseases.