A Cause of Diarrhea in a Patient with Selective Immunoglobulin A Deficiency

Abstract

Aim. To present a clinical case with differential diagnosis of the cause of diarrhea in a patient with selective IgA deficiency.Key findings. A 46-year-old woman complained of a mushy stool without pathological impurities up to 5 times a day. An outpatient colonoscopy revealed signs of terminal ileitis. The patient’s medical history included selective IgA and vitamin B12 deficiency. Despite the absence of antibodies to parietal cells and intrinsic factor, a diagnosis of autoimmune gastritis was established on the basis of histologically confirmed atrophy of the stomach; decrease in serum pepsinogen I and the ratio of pepsinogen I to pepsinogen II, hypergastrinemia; vitamin B12 deficiency; proven autoimmune thyroiditis (antibodies to thyroglobulin and thyroid peroxidase in the diagnostic titre). Histologically, lymphoid hyperplasia of the stomach was determined. Colonoscopy revealed erosive terminal ileitis and colitis, as well as an increase in the lymphoid follicles of the sub-mucosal layer in the ileum and all parts of the colon, which gave a rough pattern to the mucosa. Histological examination revealed pronounced follicular hyperplasia of the lymphoid tissue of the ileum and colon. The clinical diagnosis was established as follows. The combined main disease: 1. Selective IgA deficiency with a nodular lymphoid hyperplasia of the stomach, small and large intestine. 2. Autoimmune gastritis with erosions in the gastric fornix. Vitamin B12 deficiency. Concomitant diseases: Autoimmune thyroiditis.Conclusion. The presented clinical observation demonstrates the importance of recognizing nodular lymphoid hyperplasia, which is established as the cause of diarrhea in a patient with selective IgA deficiency after excluding the diagnosis of Crohn’s disease. A specific feature of the presented clinical case is a combination of autoimmune gastritis and autoimmune thyroiditis with selective IgA deficiency.