[Cobalamin deficiency: neurological aspects in 27 cases]. / Carences en cobalamine: aspects neurologiques chez 27 patients.

ABSTRACT

INTRODUCTION: Combined medullar sclerosis, together with peripheral sensory neuropathies, is the most common neurological manifestation observed in cobalamin deficiency. Biermer's disease is the predominant cause. Other clinical and etiological aspects are nevertheless frequent, although underestimated. METHODS: This retrospective study included patients with neurological symptoms and cobalamin (B12 vitamin) deficiency confirmed by laboratory tests collected over a period of 11 years. RESULTS: Twenty-seven cases were analyzed. Mean age was 47 years and there were 11 women and 16 men. Distribution of the neurological syndromes was combined medullar sclerosis in 18 patients (67%), sensory neuropathies in 30% of cases and sensory-motor neuropathies in 15%. One patient had fronto-subcortical dementia with good improvement after vitamin replacement. In addition, autonomic dysfunction was noted in six patients (orthostatic symptomatic hypotension and/or urinary dysfunction and/or erectile failure). Dysautonomia revealed cobalamin deficiency in three patients with a good and fast response to the cobalamin therapy in all cases. Biermer's disease was diagnosed in 17 patients (63%) and a likely syndrome of nondissociation of cobalamin in two patients. One patient had Crohn's disease and no etiology was found in seven patients. In five patients (19%), nitrous oxide undoubtedly induced decompensation of latent cobalamin deficiency; four after a general anesthesia and one by chronic professional exposure. Outcome was very good in 46% of patients after vitamin replacement, particularly if treatment was started rapidly. DISCUSSION: The findings in this series highlight the frequency of autonomic dysfunction sometimes revealing cobalamin deficiency with a fast and good response to vitamin replacement and the frequency of neurological disorders following decompensation triggered by general anesthesia using nitrous oxide in patients with latent cobalamin deficiency.