Cobalamin Deficiency: Clinical Picture and Radiological Findings

Abstract

Vitamin B12 deficiency causes a wide range of hematological, gastrointestinal, psychiatric and neurological disorders. Hematological presentation of cobalamin deficiency ranges from the incidental increase of mean corpuscular volume and neutrophil hypersegmentation to symptoms due to severe anemia, such as angor, dyspnea on exertion, fatigue or symptoms related to congestive heart failure, such as ankle edema, orthopnea and nocturia. Neuropsychiatric symptoms may precede hematologic signs and are represented by myelopathy, neuropathy, dementia and, less often, optic nerve atrophy. The spinal cord manifestation, subacute combined degeneration (SCD), is characterized by symmetric dysesthesia, disturbance of position sense and spastic paraparesis or tetraparesis. The most consistent MRI finding is a symmetrical abnormally increased T2 signal intensity confined to posterior or posterior and lateral columns in the cervical and thoracic spinal cord. Isolated peripheral neuropathy is less frequent, but likely overlooked. Vitamin B12 deficiency has been correlated negatively with cognitive functioning in healthy elderly subjects. Symptoms include slow mentation, memory impairment, attention deficits and dementia. Optic neuropathy occurs occasionally in adult patient. It is characterized by symmetric, painless and progressive visual loss. Parenteral replacement therapy should be started soon after the vitamin deficiency has been established.

Vitamin B-12 and Cognition in Children

“…Cobalamin is a cofactor for methionine synthase, an enzyme that converts 5-methyltetrahydrofolate to tetrahydrofolate via remethylation of homocysteine (tHcy) 7 to methionine (3). Methionine synthase is required for the production of S-adenosylmethionine, which is involved in >100 methylation reactions in the body and is an important methyl donor for neurotransmitter synthesis and maintenance of cellular integrity (4).…”

Demyelinating lesions as a presenting feature of pernicious anaemia: Case report and literature review

“…Similar neuro-haematologic dissociations have been previously reported by others. [12] Similarly, demyelination involving the brain but not the spinal cord has been reported in patients with cobalamin deficiency. In these patients, hyperintensity signals are typically restricted to the subcortical and the periventricular white matter.…”

Chronic Intoxication With “Laughing Gas” (Nitrous Oxide) as a Cause of B12 Deficiency Myelopolyneuropathy in Young Adults

“…В связи с этим развитие В 12 -дефицитного состояния и его последствий у пожилых людей, веге-тарианцев, а также лиц, страдающих хроническим алкоголизмом или хроническими заболеваниями же-лудочно-кишечного тракта, понятно и ожидаемо. На-стороженность в отношении дефицита витамина В 12 присутствует и при повышенной потребности в нем в период беременности, при приеме ряда препаратов (оральные контрацептивы, ингибиторы протонной пом-пы, антагонисты Н 2 -рецепторов, метформин, колхицин, холестирамин), а также при наличии генетичес кой предрасположенности (синдром Имерслунда-Грес бе-ка, ювенильная пернициозная анемия, врожденные нарушения метаболизма кобаламина) [1][2][3][4]. В то же вре-мя у относительно здоровых молодых людей, не имею-щих ограничений в питании, развитие неврологичес-ких осложнений, связанных с дефицитом витамина В 12 , приводит врача к замешательству.…”