Document resource
Introduction Intestinal capillariasis due to Capillaria philippinensis is an underrecognized but life-threatening parasitic infection endemic to Southeast Asia, capable of causing severe PLE through autoinfective mucosal invasion. Concurrent mesenteric vascular complications and primary autoimmune hematologic disease have not been previously described in this context.Methods A Thai male in his 60s with hypertension, dyslipidemia, and type 2 diabetes mellitus presented with chronic abdominal pain, non-voluminous watery diarrhea, 6 kg weight loss over two months, and progressive anasarca. CT imaging suggested a vascular etiology. Following failure of anticoagulation to resolve symptoms, investigation escalated to video capsule endoscopy (VCE) and targeted stool concentration techniques. Hematologic workup was performed for concurrent hemolysis.Results CT confirmed severe stenosis of the ileal branch of the SMV with partial thrombosis and diffuse small bowel wall thickening; anticoagulation was initiated. A comprehensive thrombophilia screen was unremarkable. VCE demonstrated diffuse villous atrophy, mucosal edema, and scalloped jejunal folds ( figure 1). Initial stool by direct smear was negative; targeted re-examination using concentration techniques on day 3 identified Capillaria philippinensis and Opisthorchis viverrini. Albendazole and praziquantel produced rapid diarrhea resolution; albumin recovered from 1.5 to 3.1 g/dL at two months. Paradoxically, hemolysis worsened post-treatment (hemoglobin nadir 5.6 g/dL; DAT IgG-negative, C3d 3+). Malignancy and systemic autoimmune disease were excluded. The divergence between enteropathy resolution and worsening hemolysis following parasite eradication, together with a refractory course on prednisolone and response to rituximab, supported primary cold agglutinin disease (CAD) unmasked by physiological stress.Conclusions This case highlights a complex multisystem presentation in which parasitic mucosal injury, together with superior mesenteric vein stenosis, likely exacerbated protein loss. A negative stool examination does not exclude capillariasis in endemic areas; concentration techniques are essential before ruling out the diagnosis. Video capsule endoscopy is valuable in unexplained protein-losing enteropathy. In addition, this case suggests that intestinal capillariasis may contribute to the development of superior mesenteric vein thrombosis.Abstract P385 Figure 1Video capsule endoscopy demonstrating (A, B) diffuse mucosal edema and characteristic scalloped appearance of the jejunal valvulae conniventes (white arrows), and (C, D) multiple sessile polypoid lesions within the jejunal lumen (yellow arrows), consistent with severe protein-losing enteropathy due to Capillaria philippinensis infection