Infantile vomiting caused by vitamin B12 deficiency: A case report

Abstract

Vitamin B12 deficiency is an important but often overlooked cause of feeding difficulties, vomiting, and neurodevelopmental delay in early infancy. Early diagnosis and treatment are essential to prevent permanent neurological damage. We report the case of a 49-day-old male infant admitted with restlessness, refusal to feed, and recurrent non-projectile vomiting after breastfeeding. The patient was exclusively breastfed. The family medical history was unremarkable. The mother was on a cow's milk elimination diet, and the patient was on anti-reflux medical treatment with approaches to prevent overfeeding and reflux. The volume and frequency of the vomiting were gradually increasing. Lethargy, hypotonia, and hypoactivity were notable on initial assessment. No abnormal hematological values were found, and serum vitamin B12 levels were low. The mother's serum vitamin B12 levels were also found to be inadequate. The infant's symptoms improved with parenteral hydroxycobalamin. In conclusion, this case underlines the importance of considering vitamin B12 deficiency in the differential diagnosis of persistent vomiting and neurodevelopmental delay in infants, particularly in settings where maternal malnutrition is prevalent. Prompt diagnosis and appropriate treatment lead to rapid clinical improvement and prevent long-term complications. Clinician awareness and early screening strategies in high-risk populations could play a crucial role in improving outcomes.

Cite this article as: Çelik C, Çetin E, Vitrinel A. Infantile vomiting caused by vitamin B12 deficiency: A case report. D J Med Sci 2026;12(2):105-110. doi: 10.5606/fng. btd.2026.245.

C.Ç.: Contributed to the patient's clinical management, study concept and design, data collection, literature review, and drafting of the manuscript; E.Ç.: Contributed to the data collection and literature review; A.V.: Contributed to the study supervision, critical revision, and final revision of the manuscript. All authors read and approved the final manuscript.

The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Data Sharing Statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.

The authors received no financial support for the research and/or authorship of this article.

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