Dhand Upinder K
Department of Neurology, University of Missouri, 1 Hospital Drive, M178, Columbia, MO 65212, USA.
Respir Care. 2006 Sep;51(9):1024-40; discussion 1040-1.
Motor weakness in a patient in the intensive care unit (ICU) may be related to (1) pre-existing neuromuscular disorder that leads to ICU admission, (2) new-onset or previously undiagnosed neurological disorder, or (3) complications of non-neuromuscular critical illness. Neuromuscular syndromes related to ICU treatment consist of critical illness polyneuropathy, critical illness myopathy, and prolonged neuromuscular blockade, and are now recognized as a frequent cause of newly acquired weakness in ICU patients. Clinical features include quadriparesis, muscle wasting, and difficulty weaning from the ventilator. Evaluation of these patients is based on knowledge of clinical setting and predisposing factors, focused neurological examination, detailed electrophysiological investigation, serum creatine kinase level, other laboratory studies as needed, and histological examination of muscle biopsy. If a central nervous system (brain or spinal cord) lesion is suspected, neuroimaging studies are required. In addition to conventional nerve conduction and needle electromyography, phrenic nerve conduction, diaphragm electromyography, blink reflex, and (recently) the technique of direct muscle stimulation have been employed. Critical illness polyneuropathy is an axonal motor and sensory neuropathy that often follows sepsis and multiorgan failure. Risk factors for critical illness myopathy are corticosteroids and neuromuscular blocking drugs, acute respiratory illness, and organ transplant. Three subtypes (acute necrotizing myopathy, thick myosin filament loss myopathy, and type II fiber atrophy) are recognized. Major differential diagnoses of critical illness related paralysis are incidental Guillain-Barré syndrome and unmasked myasthenia gravis. Rarely, atypical presentation of amyotrophic lateral sclerosis, polymyositis or other myopathies, and precipitation of porphyria or rhabdomyolysis due to drugs used in the ICU have been described. Recently a poliomyelitis-like flaccid paralysis due to West Nile virus infection was reported. A subgroup of patients with myasthenia gravis with muscle-specific tyrosine kinase antibody is noted to present as respiratory crisis. Muscle biopsy in ICU paralysis syndromes may be helpful in arriving at a specific diagnosis or to classify the type of critical illness myopathy. Nerve biopsy is only rarely indicated.
重症监护病房（ICU）患者的肌无力可能与以下因素有关：（1）导致患者入住ICU的既往神经肌肉疾病；（2）新发或先前未被诊断出的神经系统疾病；或（3）非神经肌肉危重症的并发症。与ICU治疗相关的神经肌肉综合征包括重症疾病多发性神经病、重症疾病肌病和长时间神经肌肉阻滞，目前已被确认为ICU患者新获得性肌无力的常见原因。临床特征包括四肢瘫、肌肉萎缩和脱机困难。对这些患者的评估基于对临床情况和易感因素的了解、重点神经系统检查、详细的电生理检查、血清肌酸激酶水平、必要时的其他实验室检查以及肌肉活检的组织学检查。如果怀疑有中枢神经系统（脑或脊髓）病变，则需要进行神经影像学检查。除了传统的神经传导和针极肌电图检查外，还采用了膈神经传导、膈肌肌电图、眨眼反射以及（最近）直接肌肉刺激技术。重症疾病多发性神经病是一种轴索性运动和感觉神经病，常继发于脓毒症和多器官功能衰竭。重症疾病肌病的危险因素包括皮质类固醇、神经肌肉阻滞剂、急性呼吸道疾病和器官移植。已确认有三种亚型（急性坏死性肌病、粗肌球蛋白丝丢失性肌病和II型纤维萎缩）。与重症疾病相关的瘫痪的主要鉴别诊断包括偶发性吉兰-巴雷综合征和隐匿性重症肌无力。很少有报道称，重症监护病房使用的药物会导致肌萎缩侧索硬化症、多发性肌炎或其他肌病的非典型表现，以及卟啉病或横纹肌溶解症的发作。最近有报告称，西尼罗河病毒感染可导致类似脊髓灰质炎的弛缓性瘫痪。有一组肌肉特异性酪氨酸激酶抗体阳性的重症肌无力患者会表现为呼吸危象。ICU瘫痪综合征患者的肌肉活检可能有助于做出明确诊断或对重症疾病肌病的类型进行分类。神经活检仅在极少数情况下需要进行。
