Case Report: Six infants with primary intestinal lymphangiectasia: clinical manifestations of refractory cases and preliminary stratified clinical management experience

Objective This case series collected clinical data of six biopsy-confirmed infants with primary intestinal lymphangiectasia(PIL), summarized distinct clinical manifestations of refractory cases, and shared preliminary experience of risk-stratified clinical management for reference in rare pediatric gastrointestinal practice. Methods We retrospectively enrolled six consecutive infants diagnosed with PIL via gastroscopic mucosal biopsy between January 2021 and June 2024. Patients were categorized into a favorable-response group (4 cases) and a refractory group (2 cases) according to clinical outcomes after 4 weeks of standardized exclusive medium-chain triglyceride (MCT) formula therapy. All clinical manifestations, laboratory indices, endoscopic and pathological findings, and long-term follow-up data were descriptively summarized without intergroup statistical comparisons. Results All six infants presented with chronic watery diarrhea and generalized pitting edema; serous cavity effusion was detected in four patients, and hypocalcemic convulsions occurred only in the two refractory cases. Hypoalbuminemia and peripheral lymphocytopenia were universal laboratory abnormalities. Serum immunoglobulin G (IgG) levels could be falsely normal in patients receiving pre-admission intravenous immunoglobulin, which cannot exclude PIL diagnosis. Two endoscopic subtypes (edematous and granular) were identified. Pathological lymphatic dilation extending to the submucosa was exclusively observed in refractory infants. The combination of serous cavity effusion, serum albumin < 20 g/L, and hypocalcemic convulsions was only present in the two patients with treatment failure. One refractory child required long-term intermittent intravenous protein supplementation, while the other died of multiple organ dysfunction 3 months after admission. Conclusions Clinical manifestations vary greatly among infants with PIL. The concurrent occurrence of serous cavity effusion, serum albumin < 20 g/L and hypocalcemic convulsions is a prominent clinical feature unique to refractory cases in this small sample. We shared preliminary stratified clinical management experience based on our single-center observation, and further large-sample multicenter studies are needed to verify our findings.