This protocol addresses autoimmune metaplastic atrophic gastritis in the setting of pernicious anemia — a vitamin B12 deficiency anemia arising from impaired gastric intrinsic factor production due to the underlying autoimmune process.
The patient has autoimmune metaplastic atrophic gastritis complicated by pernicious anemia (vitamin B12 deficiency anemia). This comorbidity requires management directed at the hematologic consequences of the gastric condition alongside the underlying disease.
The initial strategy centers on rapid parenteral correction of the vitamin B12 deficiency, followed by lifelong maintenance, with concurrent oral iron supplementation to support a full hematologic response.
Therapy aims to reverse all abnormal hematologic changes. Serum MMA and plasma homocysteine normalize within days to weeks; macrocytosis generally resolves within the first month of treatment, while hemoglobin normalization follows on a longer timeline.
DOI: 10.14309/ajg.0000000000002968
When pernicious anemia, with or without extra-hematologic manifestations of vitamin B12 deficiency, is present, the initial strategy involves the rapid replenishment of vitamin B12 deficiency by parenteral supplementation followed by lifelong maintenance on vitamin B12, and oral iron supplementation are needed for full hemoglobin response.
The vitamin B12 therapy reverses all abnormal hematologic changes.
Serum MMA and plasma homocysteine levels normalize within the first 5 days to 2 weeks, and of serum vitamin B12 after 2 weeks of treatment.
During the first month of treatment, macrocytosis generally disappears, whereas the normalization of hemoglobin would take longer.
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