Niedobór witaminy B12 jako przyczyna nieustępujÄ cych trudności we wprowadzeniu posiłków uzupełniajÄ cych u niemowlęcia - opis przypadku

Vitamin B12 deficiency is rare in the paediatric population. The most common cause is a diet low in animal products. Particularly at risk are infants exclusively breast-fed by mothers with hypovitaminosis B12. Much rarer causes include disorders of cobalamin absorption, transport or metabolism. There are mainly haematological, neurological and gastrointestinal symptoms. Diagnostic tests should include complete blood count with differential, including the MCV and RDW, the concentration of ferritin, folic acid and cobalamin in the serum and plasma homocysteine, and methylmalonic acid excretion in urine. We present the case of 10-month-old girl breast fed, admitted to the Paediatric Department due to inhibition of weight gain and developmental delay. Among the first symptoms of vitamin B12 deficiency, which occurred in the child 6 months of age, was refusal to solid food. Increased MCV and RDW with normal haemoglobin values were observed in blood counts performed in 7 months of age. During hospitalization we noticed significantly elevated plasma homocysteine levels and a very large excretion of methylmalonic acid in the urine, which quickly normalized after the start of treatment with cyanocobalamin. At the beginning of therapy the benign myoclonic jerks occurred, which resolved spontaneously after a few days. Regression of neurological symptoms was not fully satisfactory. Lack of acceptance of foods other than breast milk can be one of the first signs of vitamin B12 deficiency in infants and contribute to the severity of the deficit.