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Endgames Case Report

A woman with macrocytic anaemia and confusion

BMJ 2014; 349 doi: (Published 08 July 2014) Cite this as: BMJ 2014;349:g4388

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In the very interesting case study reminding us about B12 deficiency as the cause of confusion in the elderly, the authors have overlooked food-cobalamin malabsorption (FCM) as the cause of B12 deficiency [1]. Although metformin is a possible factor in this scenario, the syndrome of FCM is more likely. FCM is the main cause of vitamin B12 deficiency in elderly patients with one report noting up to 60% in 92 patients aged over 65 years [2]. In this condition, there is inability to release vitamin B12 from food or Vitamin B12-binding protein and can be seen in patients in the presence of sufficient B12 intake [3]. It is primarily caused by atrophic gastritis and since approximately half of patients older than 80 years have gastric atrophy that might or not be related to H. pylori infection, this can be a common aetiological factor [4].

H.pylori relation is important to bear in mind since in this case; since here the vitamin deficiency can be corrected by antibiotic treatment. Atrophic gastritis from long-term use of antacids can also be a cause for FCM in addition to chronic alcoholism [2]. Another reason to diagnose FCM as a cause for B12 deficiency is that oral cyanocobalamin can be used as treatment, at least in the non-severe cases avoiding the inconvenience of intramuscular injections in the long-term [5]. In this contest, a systematic review has suggested that high doses of oral vitamin B12 may be as effective as intramuscular administration in obtaining short-term haematological and neurological responses in vitamin B12-deficient patients [6].

1. Sugrue A, Egan A, O'Regan A. A woman with macrocytic anaemia and confusion. BMJ. 2014; 349: g4388.
2. Andrès E, Affenberger S, Vinzio S, et al. Food-cobalamin malabsorption in elderly patients: clinical manifestations and treatment. Am J Med. 2005;118(10):1154-9.
3. Carmel R. Current concepts in cobalamin deficiency. Annu Rev Med. 2000;51:357–375.
4. Carmel R, Aurangzeb I, Qian D. Associations of food-cobalamin malabsorption with ethnic origin, age, Helicobacter pylori infection, and serum markers of gastritis.Am J Gastroenterol 2001;96:63-70.
5. Dali-Youcef N, Andrès E. An update on cobalamin deficiency in adults. QJM. 2009;102(1):17-28
6. Vidal-Alaball J, Butler CC, Cannings-John R, et al. Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency.Cochrane Database Syst Rev 2005;CD004655

Competing interests: No competing interests

21 July 2014
Jecko Thachil
Consultant HAematologist
Manchester ROyal Infirmary
Oxford road, Manchester