BACKGROUND: Vitamin B12 deficiency is often diagnosed with hematological 
manifestations of megaloblastic macrocytic anemia, which is usually the initial 
presentation. Neurological symptoms are often considered to be late 
manifestations and usually occur after the onset of anemia. Sub acute combined 
cord degeneration, which is a rare cause of myelopathy is however the commonest 
neurological manifestation of vitamin B12 deficiency.
CASE PRESENTATION: We present a case of a 66 year old Sinhalese Sri Lankan 
female, who is a strict vegetarian, presenting with one month's history 
suggestive of Sub-acute combined cord degeneration in the absence of 
haematological manifestations of anaemia. Her Serum B12 levels were 
significantly low, after which she was treated with hydroxycobalamine 
supplementation, showing marked clinical improvement of symptoms, with 
normalization of serum B12 levels. Hence, the diagnosis of vitamin B12 
deficiency was confirmed retrospectively.
CONCLUSION: Vitamin B12 deficiency could rarely present with neurological 
manifestations in the absence of anaemia. Therefore a high index of suspicion is 
necessary for the early diagnosis and prompt treatment in order to reverse 
neurological manifestations, as the response to treatment is inversely 
proportionate to the severity and duration of the disease.