Retrospective examination of diagnoses in the follow-up of children with high vitamin B12 levels

There is no specific approach to the importance of high serum vitamin B12 levels in children. As a result the clinicians are worried about the subject. There are studies in the literature that associate high serum vitamin B12 levels with an increased risk of hematological diseases and solid tumors, liver disease, renal failure and autoinflammatory diseases. In this study, 308 patients whose vitamin B12 level was found to be above 1000 pg/ml without taking vitamin B12 supplements when they applied to Hacettepe University Faculty of Medicine General Pediatrics Department between 2014 and 2020 were retrospectively examined. 157 (51%) of the patients were male and 151 (49%) were female. The ages of the patients ranged from 44 days to 18 years, and the mean age (Mean±SD) was 4.84±4.23 years. When the current diagnoses of the patients in our study were examined, 178 patients had no known disease (57.8%). It was observed that the most common complaints of the patients were cough (22.1%) and developmental delay (12%). At the time of admission, 85 patients had fever (26.3%) and 125 patients had signs of active infection (40.6%). Control vitamin B12 levels were checked in 191 of the patients during their follow-up and it was observed that 49 of them (25.6%) continued to have control vitamin B12 levels above 1000 pg/ml. 19 of the patients were diagnosed with immune deficiency, seven with autoimmune disease, six with liver disease, and one with kidney disease. Four patients had leukemia, two patients with acute myeloid leukemia (AML), two patients with chronic myeloid leukemia (CML); three patients with lymphoma; two patients were diagnosed with solid tumors, one with an intracranial mass and one with a pituitary adenoma. It was observed that all patients with malignancy had additional physical examination findings and additional complaints that led to the diagnosis. No significant difference was detected between patients whose initial diagnostic vitamin B12 value was below and above 1500 pg/ml. There was no diagnostic difference between patients with control vitamin B12 levels below and above 1000 pg/ml. Vitamin B12 was not considered to be an early biomarker of hematological and oncological diseases in pediatric patients, unlike the adult age group, since complaints, physical examination and laboratory findings are guiding the diagnosis in patients with malignancy accompanied with simultaneously with high vitamin B12 levels. It is thought that this study will make a significant contribution to the literature, as there are limited studies on the follow-up of patients with high levels of vitamin B12 in the childhood age group.