Gastric emptying in patients with vitamin B(12) deficiency

The clinical presentation of patients with vitamin B(12) deficiency varies in a spectrum ranging from haematological disorders to neuropsychiatric diseases. In rare cases, orthostatic hypotension, impotence, constipation and urinary retention have been attributed to autonomic nervous system dysfunction due to vitamin B(12) deficiency. The aim of this study was to evaluate the effect of vitamin B(12) deficiency on autonomic nervous system function by studying gastric emptying times ( T(1/2)). Twenty patients with newly diagnosed vitamin B(12) deficiency and 12 control patients with gastritis and normal vitamin B(12) levels were enrolled in this study. Gastroduodenoscopy, endoscopic biopsy, histopathological evaluation of the biopsy specimens and radionuclide gastric emptying studies were performed. After vitamin B(12) replacement therapy for 3 months, radionuclide gastric emptying studies were repeated. Mean gastric emptying T(1/2) in patients before and after treatment and in controls were 103.83+/-48.80 min, 90.00+/-17.29 min and 74.55+/-8.52 min, respectively. The difference in mean gastric emptying T(1/2) between patients before treatment and controls was statistically significant ( P<0.01). The statistically significant difference persisted after vitamin B(12) treatment ( P<0.05), though mean gastric emptying T(1/2) was somewhat shorter. There were no positive or negative correlations between gastric emptying T(1/2) and the following parameters: haemoglobin, vitamin B(12) level and Helicobacter pylori positivity. In conclusion, gastric emptying T(1/2) was prolonged in patients with vitamin B(12) deficiency and this prolongation was not corrected after vitamin B(12) replacement therapy. Although autonomic nervous system dysfunction due to vitamin B(12) deficiency rarely gives rise to clinical manifestations, latent dysfunction demonstrated by laboratory tests seems to be a frequent phenomenon. The level of vitamin B(12) does not correlate with the degree of autonomic nervous system dysfunction measured by radionuclide gastric emptying studies.