Department of Neurology, General Hospital of Ningxia Medical University, Yinchuan, 750001, China.
Department of Internal Medicine, The People's Hospital of Wushen Banner, Erdos, 017000, China.
J Med Case Rep. 2024 Nov 19;18(1):550. doi: 10.1186/s13256-024-04887-4.
Myasthenia gravis, which initially presents with prominent distal muscle weakness, is rare and is referred to as distal myasthenia gravis. Despite its clinical significance, the diagnosis of distal myasthenia gravis is often delayed or missed owing to mild and atypical symptoms.
We report the case of a 52-year-old ethnic Han woman who presented with task-related isolated transient right-hand weakness that began 15 years ago and lasted for 9 years without aggravation or improvement. In subsequent years, she developed right-hand stiffness with limited dexterity. More recently, this developed into bilateral hand weakness and simultaneous generalized weakness with ambulation, prompting suspicion of myasthenia gravis. Under Hertz repetitive nerve stimulation, the right facial nerve, right accessory nerve, right ulnar nerve, right radial nerve, and right median nerve showed decrements between 19.5% and 35.4%. Tests for anti-acetylcholine receptor antibodies were positive. The patient was diagnosed with distal myasthenia gravis, which evolved into generalized myasthenia gravis.
Distal myasthenia gravis can present with isolated and transient hand weakness as a lone symptom, and can persist for years before typical myasthenia gravis symptoms appear. The inclusion of myasthenia gravis in the differential diagnosis is necessary in patients with isolated distal weakness.
重症肌无力最初表现为明显的远端肌无力，较为罕见，被称为远端型重症肌无力。由于症状较轻且不典型，远端型重症肌无力的诊断常被延误或漏诊，尽管其具有重要的临床意义。
我们报告了一例 52 岁汉族女性患者的病例，其出现与任务相关的孤立性短暂右侧手部无力，始于 15 年前，持续 9 年，无加重或改善。随后几年，她出现右手僵硬，灵活性受限。最近，她发展为双侧手部无力，并伴有行走时的全身无力，这促使我们怀疑为重症肌无力。在赫兹重复神经刺激下，右侧面神经、右侧副神经、右侧尺神经、右侧桡神经和右侧正中神经的递减分别为 19.5%至 35.4%。抗乙酰胆碱受体抗体检测阳性。患者被诊断为远端型重症肌无力，后来发展为全身性重症肌无力。
远端型重症肌无力可表现为孤立性、短暂性手部无力作为唯一症状，在出现典型重症肌无力症状之前，可持续数年。对于仅出现远端肌无力的患者，有必要将重症肌无力纳入鉴别诊断。
