Siddiqui Ramsha, Canenguez Johanna, Thatikonda Nithisha, Elaneem Awab, Rodriguez Fernandez Jorge
Department of Neurology, University of Texas Medical Branch and Hospitals (UTMB), Galveston 77550, Texas, USA.
Case Rep Neurol Med. 2025 Aug 4;2025:1862715. doi: 10.1155/crnm/1862715. eCollection 2025.
Vitamin B12 deficiency can cause subacute combined degeneration (SACD) by disrupting myelin synthesis, leading to spinal cord degeneration. We present a unique case of SACD featuring symmetrical pseudoathetosis characterized by involuntary, slow, and writhing movements resulting from proprioceptive sensory impairment, which disrupts the brain's ability to accurately perceive limb position and movement and pulmonary embolism due to elevated homocysteine levels. A 34-year-old male presented with chest pain, generalized weakness, and numbness in his hands and feet. Two months prior, he experienced sharp chest pain, followed by progressive numbness and weakness in his upper and lower extremities. Neurological examination revealed no nuchal stiffness, normal cranial nerve function, and impaired light touch and vibration sensation in the lower extremities. Tremulousness in the hands and feet, suggestive of pseudoathetosis, had been present for 6 months. Laboratory tests confirmed severe vitamin B12 deficiency (< 159 pg/mL), elevated homocysteine, and pancytopenia. MRI of the spine showed hyperintense signals consistent with SACD, and a chest CT revealed a large saddle pulmonary embolus. Pernicious anemia was confirmed as the cause of vitamin B12 deficiency. The patient was treated with intravenous vitamin B12, leading to significant neurological improvement. This case is the first documented instance of SACD presenting with symmetrical pseudoathetosis in all four extremities. Recognizing this rare clinical sign is essential, as it can guide early diagnosis and treatment. In addition, hyperhomocysteinemia associated with vitamin B12 deficiency is a significant risk factor for thromboembolism, underscoring the need for screening in patients with unexplained thrombotic events.
维生素B12缺乏可通过破坏髓鞘合成导致亚急性联合变性（SACD），进而引起脊髓变性。我们报告了一例独特的SACD病例，其特征为对称性假手足徐动症，表现为本体感觉障碍导致的不自主、缓慢且扭动的动作，这会干扰大脑准确感知肢体位置和运动的能力，同时由于同型半胱氨酸水平升高还伴有肺栓塞。一名34岁男性出现胸痛、全身无力以及手脚麻木症状。两个月前，他经历了剧烈胸痛，随后上下肢逐渐出现麻木和无力。神经系统检查显示无颈项强直，颅神经功能正常，下肢轻触觉和振动觉受损。手脚震颤提示假手足徐动症，已持续6个月。实验室检查证实严重维生素B12缺乏（<159 pg/mL）、同型半胱氨酸升高和全血细胞减少。脊柱MRI显示与SACD一致的高信号，胸部CT显示一个大的鞍状肺栓塞。确诊恶性贫血为维生素B12缺乏的原因。患者接受静脉注射维生素B12治疗后，神经功能有显著改善。该病例是首例有文献记载的四肢均出现对称性假手足徐动症的SACD病例。认识到这一罕见的临床体征至关重要，因为它可指导早期诊断和治疗。此外，与维生素B12缺乏相关的高同型半胱氨酸血症是血栓栓塞的重要危险因素，这凸显了对不明原因血栓事件患者进行筛查的必要性。
