Vitamin B12 deficiency is a prevalent condition that can lead to serious neurological disorders, including subacute combined degeneration (SCD) of the spinal cord, which can result in lasting damage if not promptly treated. This report discusses a unique case of a 53-year-old female patient who presented with a one-week history of gait instability and falls, ultimately diagnosed with SCD due to severe Vitamin B12 deficiency. Notably, the patient exhibited an atypical presentation, lacking classic symptoms such as paraesthesia and hematologic abnormalities, which often accompany B12 deficiency. Clinical evaluation revealed no previous neurological deficits or hematological issues, suggesting an acute decline in B12 levels. Neuroimaging, particularly MRI of the spine, showed demyelination affecting the dorsal columns and corticospinal tracts, consistent with SCD, while excluding ischemic causes. Laboratory tests confirmed low serum B12 levels supporting the diagnosis. This case underscores the necessity for clinicians to maintain a high index of suspicion for Vitamin B12 deficiency in patients presenting with unexplained neurological symptoms. Early intervention is crucial; in this case, immediate treatment with intramuscular B12 led to significant recovery in gait stability and neurological function. The findings highlight the importance of thorough assessments and ongoing education about the diverse presentations of B12 deficiency, especially in populations at risk, such as the elderly and those with malabsorption issues.

Syeda Ariba Zehra is a resident doctor, currently working in Darent Valley Hospital, United Kingdom. She completed her medical degree in 2019 from Pakistan. She aspires to become an acute medicine consultant in the UK.