Transumbilical portal vein catheterization and insulin analysis in an infant with hypoglycemia.

We performed transumbilical portal vein catheterization and sampled portal blood selectively to carry out immunoreactive insulin (IRI) analyses in a 7-month-old girl with hypoglycemia. The IRI concentration was highest in the mid-portion of the splenic vein. Although no tumor was found at surgery, 70 per cent of the caudal pancreas was resected above the superior mesenteric vein to a point determined by preoperative investigations. Pathologic examination of the resected specimen indicated nesidioblastosis. There have been no postoperative hypoglycemic symptoms. Our technique is efficacious in reaching a diagnosis of infantile hypoglycemia.