Hunter's glossitis due to cobalamin deficiency

Specialty: Hematology.

• Hunter's atrophic glossitis
• painful shaved tongue due to B12 deficiency
• megaloblastic glossitis

Why it occurs

• Pernicious anemia (autoimmune disease characterized by the production of autoantibodies against gastric parietal cells or against intrinsic factor, preventing the absorption of vitamin B12 in the terminal ileum)
• Autoimmune or environmental atrophic gastritis (with prolonged hypochlorhydria that limits the release of cobalamin bound to food proteins)
• Prolonged strict vegan or vegetarian diet without supplementation (chronic depletion of hepatic cobalamin reserves after several years of no intake)
• Surgical resection of the terminal ileum or active ileal Crohn's disease (anatomical or functional loss of the absorption site of the cobalamin-stress factor complex)
• Bacterial overgrowth in the small intestine (bacteria consume luminal vitamin B12 before its absorption).

Initial workup

Complete blood count (will reveal macrocytic anemia with MCV >100-110 fL, with frequent leukopenia and mild thrombocytopenia associated in advanced cases); peripheral blood smear to identify macroovalocytes and the pathognomonic presence of hypersegmented neutrophils (pleokaryocytes, with more than 5 or 6 nuclear lobes); quantitative determination of serum Vitamin B12 (decreased <200 pg/mL) and serum folic acid; levels of serum methylmalonic acid (MMA) and homocysteine ​​(both markedly elevated in B12 deficiency; MDA is the most specific marker); quantification of antibodies against intrinsic factor and against gastric parietal cells to confirm autoimmune origin (pernicious anemia); Upper digestive endoscopy with gastric body biopsies to evaluate glandular atrophy and rule out intestinal metaplasia or gastric neuroendocrine tumors.

Standard management

• Cyanocobalamin — vitamin B12 for deep intramuscular administration; classic scheme of 1,000 μg daily for a week, then weekly for a month and then monthly for life in cases of irreversible malabsorption or pernicious anemia; restores cellular DNA synthesis and resolves glossitis and macrocytosis in a few weeks
• Hydroxycobalamin — alternative injectable vitamin B12 with longer plasma half-life and excellent safety profile
• Oral folic acid supplementation (should be initiated only after ruling out or concomitantly treating vitamin B12 deficiency, since correcting folate alone can aggravate or mask the irreversible neurological lesions of subacute combined degeneration).