Delirium as a result of vitamin B12 deficiency in a vegetarian female patient
European Journal of Clinical Nutrition (2013) 67, 996–997; doi:10.1038/ejcn.2013.128; published online 17 July 2013
Abstract
Vitamin B12 deficiency can manifest with haematological, gastrointestinal and neuropsychiatric signs. The neuropsychiatric symptoms may be concurrent or precede the other symptoms. The reported case is a clinical case of delirium due to vitamin B12 deficiency in a female vegetarian patient. The patient was treated with vitamin B12 supplementation. Initially, it was difficult to diagnose this patient, who presented with delirium that could have been due to multiple causes. The finding underlines the importance of conducting a complete laboratory test panel for delirium, including the blood levels of vitamin B12.
Keywords:
delirium; vitamin B12 deficiency; vegetarian
Introduction
Vitamin B12 deficiency is a public health problem that affects ~20% of elderly people.1 It can manifest as haematological, gastrointestinal or neuropsychiatric signs and symptoms with depression, dementia, catatonia and delirium, which are considered as precursors.2, 3, 4 Studies have shown a high risk of depression in elderly women with vitamin B12 deficiency compared with healthy female individuals.5, 6
The lack of cobalamin is caused by food cobalamin malabsorption and pernicious anaemia. Dietary causes of vitamin B12 deficiency are rare and typically concern elderly people. Strict vegetarianism can lead to a lack of vitamin B12 ingestion and, hence, its deficiency in the body.5
Neuropsychiatric signs and symptoms secondary to vitamin B12 deficiency can be explained by the involvement of vitamin B12, as well as folate and homocysteine, which are involved in the carbon transfer metabolism (methylation) required for serotonin production, a crucial step in monoamine synthesis.2[...]
Case presentation
Mrs G was a 62-year-old widow of Argentinean origin. She was a storekeeper and mother of four children and worked at her own kiosk. She was vegetarian, with a history of a major depressive episode 5 years ago with complete remission of the episode under venlafaxine treatment.
She was admitted to the emergency department accompanied by the police, as she was found wandering lost and confused. She complained of suffering from insomnia, fatigability and poor concentration. Following some standard physical and blood tests, no physical explanation was found to explain her symptoms, and the patient was taken to our outpatient psychiatric crisis centre. She presented moderate psychomotor retardation, confusion and partial disorientation. She had depressed mood and anxiety, poor concentration and difficulty in speech. She also complained of sleep disturbances for the last few days and fatigue. The memory deficits and insomnia had a rather acute onset over the past days and presented a fluctuation of symptom severity over hours.[...]
Upon physical examination, the patient did not present any pathologic signs or symptoms apart from hypertension (up to 190/110 mm Hg) that required antihypertensive treatment with ramipril 5 mg. The investigations revealed normal haematological and ionogram levels. Her serum vitamin B12 level was low at 91 pmol/l (135–700 pmol/l), and folic acid was normal at 22.2 μg/l (4.1–24 μg/l). Mrs G had a history of vitamin B12 deficiency without presenting neuropsychiatric symptoms at the given time. The cause of the vitamin B12 deficiency was attributed to the patient’s strict vegetarianism. We conducted viral and bacterial screening to exclude an infectious cause of the patient’s current status. The serologic results for Lyme were fairly positive for immunoglobulin M but not immunoglobulin G. The infectious disease specialist proposed a retest on the subsequent month, and the results were negative. Other investigations, including brain magnetic resonance imaging, showed diffused cortical and subcortical atrophy and some nonspecific abnormalities of the white matter concordant to the age of the patient. Neuropsychiatric tests, which were conducted 2 weeks after the beginning of the treatment in our clinic, revealed multiple cognitive deficits that could be explained by either deterioration due to the patient’s age or a depressive episode.[...]
Discussion
We report the case of a patient with delirium for whom an aetiological investigation indicated a probable vitamin B12 deficiency. We emphasise the importance of conducting a wide range of laboratory tests, including an evaluation of vitamin blood levels.
The laboratory and clinical examinations we conducted excluded infectious, vascular, neoplastic, metabolic and endocrine causes. Our patient had a previous major depressive episode in addition to high blood pressure, leading to the hypertension diagnosis, which was considered a predisposing factor of the delirium.7
The significant improvement in cognitive function, the return to a normal level of consciousness and the remission of her depressive and anxiety symptoms could be explained by the introduction of the vitamin B12 treatment, rather than escitalopram at 10 mg/day for only 8 days.8[...]
The positive clinical response to the substitution treatment and the lack of other possible causes confirmed our diagnosis of delirium due to vitamin B12 deficiency.10
In conclusion, with this case report, we would like to draw clinicians’ attention to vitamin B12 deficiency as a reversible cause of delirium and to the importance of conducting a complete laboratory work-up for delirium, including the blood levels of vitamin B12.