The neurology of autoimmune pernicious anaemia (subacute combined degeneration)

Abstract

The link between pernicious anaemia and subacute combined degeneration of the spinal cord has been recognised for nearly a century. The most common neurological presenting symptoms and signs of vitamin B12 deficiency are distal paraesthesia and loss of vibration and joint position sense. A multitude of other neuropsychiatric manifestations have been described, often responding well to treatment with vitamin B12. This chapter discusses the history of pernicious anaemia and subacute combined degeneration of the cord, the common and less common neuropsychiatric manifestations and the historically and currently recommended treatment regimens. It also touches briefly on some of the current controversies and unknowns, including the apparent dissociation between the haematologic and neurologic manifestations, the role of vitamin B12 deficiency in cognitive impairment/dementia, the use of autoantibody (anti-intrinsic factor and parietal cell antibodies) detection in the diagnosis of pernicious anaemia and the utilisation of different assays to identify B12 deficiency.