**5. Chylous ascites**

Pancreatitis is a rare cause of chylous ascites (CA) and in Literature, only few cases about acute pancreatitis are reported since its discovered in 1984 [53, 54]. Other causes related to CA are abdominal trauma, malignancies, sarcoidosis, lymphangiomatosis, yellow nail syndrome, cirrhosis, and mycobacterial infections [55]. CA diagnosis is based on the presence of a milky triglyceride- rich fluid collection in the peritoneal cavity. Patients complain about abdominal pain, distension, weight loss, oedema, anorexia, and weakness.

Diagnosis requires peritoneal fluid sampling with documentation of a lipid rich fluid, triglyceride concentration > 1.2 mM (110 mg/dl), peritoneal-to-plasma protein concentration ratio of >0.5 and presence of microscopic fat. The minimum daily volume of CA considered significant ranges between 100 ml to 600 ml [56, 57].

The pathogenesis is not completely clarified especially when CA is due to acute pancreatitis. The main possible reason is the spreading of proteolytic and lipolytic enzymes associated to necrosis of pancreatic tissue that damage the lymphatic vessels thus provoking a lymph leakage. Other possible reasons are AP related and include: splenic vein thrombosis leading to portal vein hypertension thus causing the rupture of lymphatic vessels; and the severe inflammation that could cause lymphatic vessels obstruction and lymphatic exudation [58, 59].

CA treatment is multimodal. Conservative treatment is based on total parenteral nutrition (TPN) or medium chain triglyceride (MCT)-high protein enteral feeding with or without addition of octreotide and reaches the resolution in two to six weeks in 60-100% of cases [60, 61]. Interventional and surgical approaches should be reserved for cases in which conservative treatment has failed. A second line therapy is bipedal lymphangiography (BPLAG) with lipiodol. This technique permits to identify the normal lymphatic stream and locate the leakage site or the obstruction site. The accumulation of injected lipiodol determines an inflammatory response that acts as an embolic agent and determines leakage resolution in up to 70% of cases [62].

Van der Gaag and colleagues has considered any duration of chylous ascites, longer than 14 days despite therapy, a requirement for surgical intervention [63]. Surgical treatment may vary from a peritoneovenous shunt to open surgical ligation of the leaking lymphatics [64]. Surgical approach should be chosen only in case of persistent CA despite treatment, symptomatic patients, or impossibility to perform interventional radiology.
