Authors: Ilyas El Kassimi , Nawal Sahel , Meryem Zaizaa , Zineb El Bougrini , Adil Rkiouak , Youssef Sekkach

Abstract

Background: Cobalamin (vitamin B12) deficiency is a frequent, under-recognized cause of anemia in older adults and may present with severe cytopenias and neurological involvement.

Methods: Retrospective descriptive study of hospitalized patients aged 65 years and older (January 2012–December 2025) with hemoglobin <12 g/dL and serum vitamin B12 <187 pg/mL. Patients with iron/folate deficiency, inflammatory anemia, chronic kidney disease, hemolysis, or myelodysplasia were excluded. Clinical features, laboratory findings, etiologies, treatment, and outcomes were summarized descriptively.

Results: Twenty-four patients were included; 75.0% were men. Mean age was 73.6 years (65–90) and mean diagnostic delay was 65 days. Gastrointestinal manifestations occurred in 83.3%, neurological manifestations in 50.0%, and hemorrhagic presentation in 8.3%. Mean hemoglobin was 8.2 g/dL, mean corpuscular volume (MCV) 110.5 fL, and 41.7% had pancytopenia. Etiologies are summarized in Figure 1. All patients received intramuscular hydroxocobalamin; 25.0% required transfusion; reticulocytosis was documented in 83.3% within a mean of 8 days.

Conclusion: Cobalamin deficiency should be considered in older adults with anemia, macrocytosis, or cytopenias—especially when gastrointestinal or neurological features are present. Early etiologic assessment and timely replacement therapy may reduce persistent neurological sequelae.

Keywords: Vitamin B12 deficiency; macrocytic anemia; aged; pernicious anemia; malabsorption; pancytopenia.