Department of Internal Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
Department of Pathology, King Saud University, Riyadh, Saudi Arabia.
J Coll Physicians Surg Pak. 2022 Dec;32(12):SS168-SS170. doi: 10.29271/jcpsp.2022.Supp0.SS168.
Myasthenia gravis (MG) affects the ocular, bulbar, and proximal limb muscles. The involvement of distal limb muscles is uncommon. MG-related weakness that severely affects the finger flexors and spares finger extensors and intrinsic hand muscles have never been reported. Here, we report a 35-year-old woman with acetylcholine receptor-antibody positive generalised MG who presented with severe bilateral asymmetric (left worse than right) finger flexor weakness during an MG relapse. The remaining muscles including the median and ulnar intrinsic hand muscles were normal. Repetitive nerve stimulation test showed decremental responses of more than 10%. Magnetic resonance imaging showed short-T1 inversion recovery sequences and increased signal intensities in the volar forearm muscles. Needle electromyography revealed fibrillations and positive sharp waves, small amplitude, short-duration, and polyphasic early recruiting motor unit action potentials. Myositis-specific autoantibodies were negative. Muscle biopsy showed neurogenic features. The patient had a good recovery with immunotherapy. We conclude that clinicians should be aware that marked weakness of the finger flexors can occur as a result of an MG relapse and may require early aggressive therapy. Key Words: Electromyography, Finger flexors, Muscle, Biopsy, Myasthenia gravis.
重症肌无力（MG）影响眼肌、延髓肌和近端肢体肌肉。远端肢体肌肉受累并不常见。MG 相关的肌无力严重影响手指屈肌，而手指伸肌和手部内在肌肉不受累，这种情况从未有报道过。在这里，我们报告一例 35 岁女性，乙酰胆碱受体抗体阳性的全身性 MG 患者，在 MG 复发时出现严重双侧不对称（左侧比右侧更严重）的手指屈肌无力。其余肌肉，包括正中神经和尺神经支配的手部内在肌肉正常。重复神经刺激试验显示超过 10%的递减反应。磁共振成像显示掌侧前臂肌肉短 T1 反转恢复序列和信号强度增加。肌电图显示纤颤波和正锐波，小幅度，短时限，多相早期募集运动单位动作电位。肌炎特异性自身抗体阴性。肌肉活检显示神经源性特征。患者经免疫治疗后恢复良好。我们的结论是，临床医生应该意识到，MG 复发可能会导致手指屈肌明显无力，需要早期积极治疗。
肌电图、手指屈肌、肌肉、活组织检查、重症肌无力。
