Unusual Presentation of Vitamin B₁₂Deficiency

Abstract

Cobalamin (vitamin B 12 ) deficiency could be masked by lack of hematological abnormalities or by concomitant conditions associated with microcytosis such as iron deficiency and thalassemia traits. We examined blood and bone marrow morphology, serum ferritin and vitamin B 12 levels and fasting gastric pH in nine patients who were suspected to have vitamin B 12 deficiency with unusual manifestations. Two patients had neurological symptoms without any hematological abnormalities, two had thalassemia traits, and five had achlorhydria with severe iron and B 12 deficiencies. Serum B 12 was low in all cases, bone marrow was diagnostic in seven cases and peripheral blood showed hypersegmentation of neutrophils only in five cases. We conclude that vitamin B 12 deficiency could be masked by lack of hematological changes or by concomitant causes of microcytosis and that serum vitamin B 12 levels as well as other ancillary tests should be considered in all suspected cases. Ann Saudi Med 1993;13(3):226-230.A Al-Momen, Unusual Presentation of Vitamin B12 Deficiency. 1993; 13(3): 226-230 Despite the development and wide application of simple methods for measurement of serum cobalamin (vitamin B 12 ), there are still situations in which the diagnosis of vitamin B 12 deficiency is a real challenge [1,2]. Vitamin B 12 deficiency may be missed due to concomitant presentation with other causes of anemia such as thalassemia and iron deficiency or due to absence of classical hematological abnormalities such as ovomacrocytosis and hypersegmented neutrophils. This is likely to develop in patients with concomitant microcytosis due to such conditions as thalassemia traits or iron deficiency. Patients with achlorhydria, for instance, commonly present with unresponsive iron deficiency anemia due to masked vitamin B 12 deficiency [3][4][5][6][7][8][9][10][11]. Vitamin B 12 deficiency may present with neuropsychiatric manifestations in the absence of hematological abnormalities [12][13][14][15][16][17][18][19][20][21][22][23][24].Vitamin B 12 deficiency may even present with normal or elevated serum B 12 when associated with myeloproliferative disorders, leukocytosis, exposure to nitrous oxide, or conditions with increased cobalamin binders and/or analogues [25][26][27][28][29].In this paper we report nine cases (Table) with cobalamin deficiency in whom the diagnosis was delayed because of unusual presentation. Vitamin B 12 was measured when cobalamin deficiency was suspected because of unexplained neuropsychiatric symptoms or unresponsive iron deficiency anemia. Patients Case 1:Forty-eight-year-old male with history of headache, irritability, back pain, weakness, and numbness of both lower limbs for two years prior to referral to our hospital. His symptoms worsened while he was under investigation, which included normal blood count, blood sugar, liver and kidney functions, bone marrow examination, lumbosacral x-ray, lumbosacral magnetic resonance imaging (MRI), nerve conduction studies and psychiatric assessment. Physical examination sh...