Vitamin B in paediatric neurology

Aims: The group of B vitamins consists of eight vitamins which act as coenzymes in various metabolic pathways.

Methods: Three cases of vitamin B deficiency are described.

Results: Vitamin B₁ deficiency (thiamine)-primarily associated with chronic alcoholism-is attributable to malnutrition or diet deficiencies of various different causes. The acute neurological disorder associated with thiamine deficiency is Wernicke encephalopathy. Main symptoms are ocular abnormalities, ataxia, and mental status changes. Thiamine substitution should be initiated immediately, either IV or IM. In delayed therapy begin estimated mortality is approximately 20%. Approximately 85% of surviving patients develop a chronic encephalopathy (Korsakoff syndrome). It is mandatory that thiamine is given before or concomitantly with glucose, because glucose alone can precipitate the disorder in thiamine-deficient individuals.

Vitamin B₆ absorbed from food comprises three vitamers which are converted in the body to a single biologically active form: pyridoxal phosphate.

Antiquitin deficiency (mutation in the ALDH7A1 gene) results in a deficiency state. Clinical course leads to recurrent episodes of status epilepticus within the first weeks or months of life, which can only be treated with vitamin B₆ (or pyridoxal phosphate). Prognosis varies; even early intrauterine therapy cannot guarantee normal neurological development of the children. Late-onset seizures are rare; however, cases up until the third year of life have been reported.

Incidence of vitamin B₁₂ deficiency in European infants is rare. Common symptoms are failure to thrive, neurodevelopmental delay and regression, microcephaly, and apathy. The most frequent cause is a nutrition deficiency, the major risk factors being a vegan diet (substrate deficiency) or atrophic gastritis (impaired absorption) in breastfeeding mothers.

Therapy consists of a substitution, during the course of which myoclonus, tremor, and epileptic seizures can occur, which however can be normally treated.

Conclusion: In neurological symptoms deficiencies of B vitamins should be taken into account.