Carmel R, Gott P S, Waters C H, Cairo K, Green R, Bondareff W, DeGiorgio C M, Cummings J L, Jacobsen D W, Buckwalter G
Department of Medicine, University of Southern California School of Medicine 90033, USA.
Eur J Haematol. 1995 Apr;54(4):245-53. doi: 10.1111/j.1600-0609.1995.tb00679.x.
Cobalamin levels are frequently low in patients with dementia, but it is unclear if they represent definable deficiency and what the mechanisms are. Therefore, patients being evaluated for dementia who had low cobalamin levels but no obvious evidence of deficiency were studied hematologically, neurologically and with metabolic tests and were re-evaluated after cobalamin treatment. Abnormalities suggestive of or diagnostic for deficiency were documented in most of the 16 demented and nondemented patients. Metabolic results: 50% of patients tested had abnormal deoxyuridine suppression and 44% had increased serum methylmalonic acid and/or homocysteine levels; these test results correlated with each other. Neurologic results: 73% of patients had clinical abnormalities, primarily mild neuropathies, not attributable to other causes, 75% had electroencephalographic abnormalities, 77% had abnormal visual evoked potentials and 33% had abnormal somatosensory potentials. Metabolic and neurologic dysfunction were present together or absent together in all but 2 cases. Cobalamin therapy improved 50-100% of the various types of abnormalities, although it did not improve cognitive function in the 13 demented patients. Food-cobalamin malabsorption was found in 60% of the patients. Despite the absence of megaloblastic anemia and rarity of traditional malabsorption of free cobalamin, low cobalamin levels in demented patients frequently represent mild cobalamin deficiency and are often associated with food-cobalamin malabsorption. Perhaps most importantly, this is accompanied not only by metabolic changes but by evidence of mild neurologic dysfunction. Their frequent reversibility by cobalamin confirms that these defects indeed arise from cobalamin deficiency. Although the long-standing dementia does not improve, treating such patients with cobalamin has other concrete benefits.
痴呆患者的钴胺素水平常常较低，但尚不清楚这些低水平是否代表可明确界定的缺乏状态以及其机制是什么。因此，对钴胺素水平低但无明显缺乏证据且正在接受痴呆评估的患者进行了血液学、神经学和代谢检查，并在钴胺素治疗后进行了重新评估。在16例痴呆和非痴呆患者中的大多数身上记录到了提示或诊断缺乏的异常情况。代谢结果：50%的受测患者脱氧尿苷抑制试验异常，44%的患者血清甲基丙二酸和/或同型半胱氨酸水平升高；这些检测结果相互关联。神经学结果：73%的患者有临床异常，主要是轻度神经病变，且并非由其他原因所致，75%的患者脑电图异常，77%的患者视觉诱发电位异常，33%的患者体感诱发电位异常。除2例患者外，代谢和神经功能障碍要么同时存在，要么同时不存在。钴胺素治疗使50 - 100%的各类异常情况得到改善，尽管在13例痴呆患者中并未改善认知功能。60%的患者存在食物钴胺素吸收不良。尽管缺乏巨幼细胞贫血且游离钴胺素传统吸收不良的情况罕见，但痴呆患者的低钴胺素水平常常代表轻度钴胺素缺乏，且常与食物钴胺素吸收不良相关。也许最重要的是，这不仅伴有代谢变化，还伴有轻度神经功能障碍的证据。它们通过钴胺素治疗常常可逆转，这证实这些缺陷确实源于钴胺素缺乏。尽管长期的痴呆没有改善，但用钴胺素治疗此类患者有其他切实的益处。
