Reversible dementia, psychotic symptoms and epilepsy in a patient with vitamin B12 deficiency.

Vitamin B12 deficiency is a common condition, typically associated with megaloblastic anaemia, glossitis and neuropsychiatric symptoms. We report the case of a patient presenting with progressive cognitive and functional deterioration, psychosis and seizures, later found to be secondary to pernicious anaemia. Importantly, the diagnosis of pernicious anaemia was only established 5 years after symptom onset and was overlooked even when the patient was under medical care, in part due to the lack of classic neurological and haematological signs associated with the condition. The patient had a remarkable neuropsychiatric recovery after vitamin replacement and psychopharmacological management. We discuss similar presentations of vitamin B12 deficiency found in the literature, symptom reversibility and the importance of its early recognition and treatment. © BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.