Carences en vitamine B 12 avec test de Schilling normal ou syndrome de non-dissociation de la vitamine B 12 de ses protéines porteuses chez le sujet âgé. Étude de 60 patients

Abstract

Purpose. – Approximately 15% of people over 60 years old have a cobalamin (Cbl) deficiency in relation with a food-cobalamin malabsorption (FCM). But to date, only case reports or small series have been reported. The aim of this study was to describe the clinical characteristics of the FCM in old subjects. Methods. – Sixty patients, at least 65 years old, presenting a Cbl deficiency related to FCM, were extracted from a cohort study of the Hôpitaux universitaires de Strasbourg, France ( n = 169). All these patients had an established diagnosis of Cbl deficiency and met the Carmel's criteria of FCM. Their clinical data were retrospectively analysed. Results. – The median age of the 60 patients was 75 years and the female/male ratio was 2.3. The principal clinical symptoms were peripheral neuropathy (35%), confusion and dementia (30%) and anemia-related manifestations such as asthenia and edemas of the legs (20%). Average hemoglobin was 10.7 ± 2.5 g/dl and average mean erythrocyte cell volume was 95.5 ± 13.8 fl. There was an anemia, a leucopenia, a thrombocytopenia and a pancytopenia in respectively 27%, 18%, 15% and 8% of the cases. Average serum vitamin B 12 and homocystein levels were with 138 ± 42 pg/ml and 22.5 ± 15.2 μmol/l. No patient had anti-intrinsic factor antibody and the Schilling's test was normal in all patients. Main disorders associated with FCM were atrophic gastritis (59%), long-term metformin or antiacid intake (17%), chronic alcohol intake (8%) and idiopathic FCM ( n = 10). Sixteen patients have been successfully treated with oral crystalline cyanocobalamin (500 ± 280 μg/d). Conclusions. – This study shows that: firstly, the Cbl deficiency related to FCM may be responsible of severe neurological and hematologic manifestations in approximately 20% of the elderly patients; secondly, the disorders associated with the FCM are multiple in old age, with mainly atrophic gastritis; and thirdly, in clinical practice, oral cyanoCbl treatment may be successful.