Role of Pernicious Anemia in Patients Admitted to Internal Medicine with Vitamin B12 Deficiency and Oral Replacement Therapy as a Treatment Option.

BACKGROUND

To determine the role of vitamin B12 deficiency in pernicious anemia and the efficacy of oral vitamin B12 replacement therapy given regardless of the etiology, and to compare the endoscopic and pathological findings in patients diagnosed with vitamin B12 deficiency.

METHODS

The study included 216 patients, aged 18 - 65 years, diagnosed with vitamin B12 level < 200 pg/mL between May 2015 and May 2016. Evaluation was made of the demographic characteristics of the patients, diseases, drugs used, dietary habits, previous use of vitamin B12 replacement therapy, family history of vitamin B12 deficiency, laboratory test values, and neurological symptoms present at the time of presentation. Endoscopy was applied to all the patients included in the study. Anti-parietal cell antibody (APCA) and anti-intrinsic factor antibody (AIFA) analyses were applied to all patients.

RESULTS

Evaluation was made of a total of 216 patients diagnosed with vitamin B12 deficiency, comprising 145 (67.1%) females and 71 (32.9%) males. The mean vitamin B12 level of the patients was determined as 127 pg/mL at the time of presentation and 334 pg/mL after treatment. APCA positivity was determined in 40 (18.5%) patients, and AIFA positivity in 5 (2.3%) patients. Atrophy was determined endoscopically in 53 (24.5%) patients and pathologically in 90 (41.7%). Helicobacter pylori positivity was determined in 196 (90.7%) patients. A diagnosis of pernicious anemia (PA) was made in 4 (1.9%) patients (patients with AIFA positivity or APCA accompanied by corpus atrophy). APCA positivity was determined but not corpus atrophy in 36 (16.7%) patients and these cases were accepted as suspected pernicious anemia. In this study of 216 patients with vitamin B12 deficiency, stomach pathologies which could cause vitamin B12 deficiency (atrophic gastritis, HP, PA) and the responses to oral replacement therapy were investigated. As vitamin B12 absorption plays a role in the pathogenesis. Vitamin B12 deficiency can lead to atrophic gastritis, and this was determined with biopsy in 41.7% of the patients. APCA positivity was determined in 18.5% of the patients investigated with respect to autoimmune atrophic gastritis (pernicious anemia) and AIFA positivity in 2.3%. A diagnosis of PA was made in 4 (1.9%) patients from autoimmune marker positivity and the presence of corpus atrophic gastritis. HP was determined in 90.7% of the patients with vitamin B12 deficiency, and although no correlation was determined between HP and atrophy, HP positivity was determined in 84 (93.3%) of the patients with pathological atrophy. From the time of diagnosis, the patients in the study were prescribed 1,000 µg/day vitamin B12. At the 40-day follow-up examination, a significant increase was observed in the vitamin B12 levels of 92.5% of the patients. At the end of the study, as oral replacement therapy was seen to be effective to a great extent, even in patients with PA, it was concluded that for patients not responding to oral replacement therapy, it would be appropriate to apply parenteral vitamin B12 treatment.

CONCLUSIONS

In developing countries such as Turkey, the role of HP infection in vitamin B12 deficiency must be kept in mind. The incidence of atrophic gastritis and pernicious anemia is higher than expected in vitamin B12 deficiency. Thus, it can be concluded that it is appropriate to investigate patients with vitamin B12 deficiency with respect to atrophic gastritis and PA, and oral replacement therapy should be the first stage in the treatment of vitamin B12 deficiency.