Subacute combined degeneration: a case of pernicious anaemia without haematological manifestations

Abnormal brain changes in a patient with vegetarian diet‑induced subacute combined degeneration: A case report

Subacute combined degeneration (SCD) is a neurological disorder caused by vitamin B12 deficiency, prevalent in the cervical and thoracic medullas, with an insidious onset and a lack of characteristic clinical manifestations. The present study describes a case of a 36-year-old female patient with SCD who demonstrated abnormal changes in the white matter of the brain. The laboratory test results showed a decrease in serum vitamin B12 levels and an increase in homocysteine levels. Magnetic resonance imaging (MRI) of the brain showed that, in addition to abnormal signals in the cervical and thoracic spine, speckled and short-striped abnormal signals were present, symmetrically distributed in the centrum semiovale. After 6 months of follow-up treatment, cranial MRI showed a significant attenuation of the symmetrical speckled and short-striped abnormal signals in the centrum semiovale. Homocysteine and serum vitamin B12 levels of the patient were within the expected range. Although, to the best of our knowledge, there have been no previous reports of alterations in the brain of patients with SCD, if these patients report neurological symptoms, clinicians should consider that these symptoms may be accompanied by inflammatory demyelination of the brain.

Cobalamin Deficiency in the Elderly

Older people are at risk for cobalamin (vitamin B₁₂) deficiency because of a number of common disorders (e.g., autoimmune gastritis) and drugs (e.g., antacids) that may alter its absorption and utilization. The prevalence of cobalamin deficiency increases with age, resulting, particularly elevated, in frail and institutionalized subjects. At variance with common sense, the diagnosis is far from simple. It requires a high degree of suspicion, due to heterogeneity and non-specificity of the signs and symptoms, ranging from macrocytosis (with or without anemia) to neuropsychiatric manifestations, that characterize several other aging-related disorders, like hematological malignancies, diabetes, hypothyroidism or vasculopathy. Furthermore, the detection of low levels of serum vitamin B₁₂ appears poorly sensitive and specific. Other biomarkers, like serum homocysteine or methylmalonic acid, have improved the diagnostic possibilities but are expensive, not widely available, and may be influenced by some confounders (e.g., folate deficiency, or chronic renal failure). Early recognition and treatment are crucial since a proportion of patients develop severe complications, such as bone marrow failure and irreversible neurological impairment. High-dose oral treatment has proven to be as effective as the parenteral route, even in subjects with malabsorption, ensuring the complete resolution in the majority of cases. In this review, we trace the essential role of cobalamin in humans, the possible causes and impact of deficiency, the diagnostic challenges and the therapeutic options, between old and emerging concepts, with a particular focus on the elderly.