[69-year-old patient with seizure of unknown origin].

Diseases associated with cobalamin deficiency often present a variety of neurological disorders apart from the well known megaloblastic anaemia as haematological manifestation. The peripheral and the central nervous system can be affected in different levels by the metabolic changes due to an impaired Vitamin B12 metabolism. Based upon an observed case we discuss the manifestation of cerebral convulsion possibly due to a secondarily acquired cobalamin deficiency. We conclude that in de novo cerebral convulsion in the elderly a cobalamin deficiency could play an important role.