Ascites and peritoneal disease: Case

This infant presents the classic picture of congenital chylous ascites, a low-gradient ascites distinguished by its milky appearance and high triglyceride content. The key to the diagnosis lies in the ascitic fluid analysis, which immediately separates this condition from the cirrhotic and nephrotic ascites that dominate the older-child differential. The well-grown, comfortable infant with no stigmata of chronic liver disease and a milky tap points away from cirrhosis and toward a primary lymphatic or peritoneal cause. ^[1]

Clinical findings

The clinical picture is that of a well infant with isolated ascites. The absence of splenomegaly, jaundice, spider naevi, and other stigmata of chronic liver disease argues strongly against cirrhosis. The absence of generalised peripheral oedema and heavy proteinuria argues against nephrotic syndrome. The scrotal oedema is a mechanical consequence of the raised intra-abdominal pressure tracking through the patent processus vaginalis, a common finding in infantile ascites and not itself diagnostic. ^[1]

The milky appearance of the ascitic fluid is the defining clue. Chylous ascites is confirmed by an ascitic triglyceride concentration exceeding that of serum, and a level of 8 mmol per litre is unequivocally chylous. The serum-ascites albumin gradient of 10 g per litre, calculated as 32 minus 22, is under the portal-hypertension threshold of 11 g per litre, confirming that the ascites is not portal-hypertensive. This combination of a low gradient and a high triglyceride is pathognomonic of chylous ascites. ^[1]