Subacute combined degeneration of the cord classically occurs in association with Addison's pernicious anaemia. Over the years improved haematological and biochemical techniques have shown that it can occur in vitamin-B.2-deficiency states other than pernicious anaemia: these include cases following gastrectomy, in which most of the intrinsic-factor-producing area may be removed, and in other cases of " malabsorption syndrome."It can also occur in association with fish-tapeworm infestation, particularly in Scandinavia (Woltman and Heck, 1937
COMMENTThese results thus showed that he was in fact deficient in vitamin B2 and so supported our diagnosis of subacute combined degeneration. The presence of free hydrochloric acid in the stomach rules out classical pernicious anaemia and the Schilling test showed that he was able to absorb vitamin B12* Thus it seemed virtually certain that his deficiency was due to an inadequate intake of vitamin B12 as a result of his most unusual diet.Surprisingly there was no anaemia, but the high fasting serum iron and early marrow changes suggested that this might have been imminent. Megaloblastic anaemia due to dietary deficiency of vitamin B12 has been recorded previously in vegans and old people existing on very precarious diets (Harrison et al., 1956;Bourne and Oleesky, 1960). In this case the relatively high intake of folic acid was probably the reason why the subacute combined degeneration developed before the anaemia.Though this neurological complication as a result of dietary deficiency has been previously reported, and reviewed by Richmond and Davidson (1958), this case seems unique in that the patient was not in the strictest sense either a vegan or a vegetarian. It was simply a food fad carried over from his younger days. Badenoch's (1954) case was similar, though his patient was described as a vegetarian. This patient's diet contained none of the usual sources of vitamin B L2' Animal protein in the form of meat and fish being the main sources, his diet had lacked both, apparently for most of his life.As he originally had no intention of changing his dietary habits we thought it safer to treat him with vitamin-B,1 iniections. On this treatment, though his symptoms have improved, the neurological signs remain virtually the same, except that the plantar responses are probably now flexor. However, his appetite improved so much that he eventually started, and is continuing to take, a normal diet, and his weight has increased from 9 st. 7 lb. to 10 st. 8 lb. (4.28 to 4.76 kg.). As we know he is able to absorb vitamin B12, we have now discontinued his injections.