Comparison of clinical and electrodiagnostic features in B12 deficiency neurological syndromes with and without antiparietal cell antibodies

Background and aims: This study was undertaken to compare the clinical and electrodiagnostic (Edx) features in autoimmune and nutritional vitamin B12 deficiency neurological syndromes. Methods: Consecutive patients with vitamin B12 deficiency neurological syndromes were evaluated and blood counts, red blood cell indices, serum chemistry, thyroid function, HIV serology, antiparietal cell antibody (APCA), serum B12, bone marrow and spinal MRI assessed. EDx studies included nerve conduction, tibial somatosensory (SEP) and motor evoked potential (MEP) to the tibialis anterior, and visual evoked potential (VEP). The results were compared between APCA positive and negative groups. Results: 57 patients aged 17-80 years (mean 45.3) were studied; 48 were vegetarians. The presenting clinical syndromes were myeloneuropathy in 25, myelopathy in 14, myeloneuroencephalopathy in 13, myeloencephalopathy in four and behavioural abnormality only in one patient. Spinal MRI in 47 patients revealed posterior spinal cord hyperintensity in 21 and cord atrophy in six. Nerve conduction was abnormal in 15%, MEP in 56.6%, SEP in 87.3% and VEP in 63.6% of patients. At 3 months, 31 patients had complete, 11 partial and three poor recovery. APCA was positive in 49% of patients. There was no difference in clinical, MRI or Edx findings or outcome between the APCA positive and negative groups. Conclusion: APCA was positive in 49% of patients with B12 deficiency neurological syndrome but their clinical, MRI and Edx changes were not different from the APCA negative group. Neurological manifestations may be caused by B12 deficiency itself rather than the underlying cause.