In protein-losing enteropathy, edema of the intestinal wall thickens the mucosa and submucosa. This creates bright, parallel lines along the folded bowel wall, producing a tiger-striped, hyperechoic mucosal pattern on ultrasound. That striped appearance specifically reflects mucosal edema and is a characteristic finding in this setting. The other options describe different organs or findings (liver nodules, dilated renal pelvis, splenomegaly) and do not produce the distinctive mucosal stripe pattern seen with intestinal edema in PLE.

When diagnosing intestinal problems, the depth of tissue sampled and the size of the biopsy matter a lot. A full-thickness, or transmural, biopsy collects all layers of the intestinal wall, so you can evaluate disease that involves beyond the mucosa and you can sample any part of the tract. That level of tissue requires an invasive approach, which explains the larger samples and the higher risk of complications like bleeding or infection. Because it’s invasive, it’s also contraindicated in patients with severe hypoproteinemia, since poor protein status impairs healing and increases the risk of wound complications. In some settings, a general practitioner with appropriate surgical training can perform this biopsy, but usually it’s done in a surgical setting. This combination of depth, sample size, and ability to biopsy any segment, with the associated invasiveness and higher complication risk, is what makes surgical biopsy the correct choice.

Protein-losing enteropathy involves loss of plasma proteins into the gut, which lowers albumin levels and reduces oncotic pressure. That drop in oncotic pressure promotes leakage of fluid into body spaces, leading to ascites and pleural effusions. It can also cause a loss of anticoagulant proteins like antithrombin III, increasing the risk of thromboembolic disease. Hyperglycemia, on the other hand, is not a characteristic sign of this condition because the problem stems from protein loss and fluid shifts, not from dysregulated glucose control. So the feature that is not listed as a clinical sign is hyperglycemia.

Lymphangiectasia starts with dilation and dysfunction of the intestinal lacteals inside the villi. When these lymphatic vessels enlarge, pressure builds and lymph—rich in protein and fat—begins to leak into the intestinal lumen. This leakage causes protein-losing enteropathy, leading to hypoalbuminemia, edema, and loss of immunoglobulins, along with impaired fat absorption and steatorrhea because the chyle cannot be properly transported. In some cases, the dilated lacteals can rupture, causing a more rapid or dramatic leakage into the lumen. This mechanism directly explains why protein-rich lymph ends up in the gut and why protein loss occurs, which is the hallmark of lymphangiectasia. Other options describe different disease processes (villous damage from infection, autoimmune enteropathy, or mucus-related malabsorption) that do not center on dilation and leakage of intestinal lymphatics.