Abdominal discomfort and inflammation of the serous membranes with minimal accumulation of fluid in the abdominal cavity are typical signs of dengue fever. Abdominal pain in dengue virus infection is commonly attributed to conditions such as gallbladder inflammation without gallstones, liver inflammation, inflammation of the pancreas, and peptic ulcers. It is extremely rare for patients with expanded dengue fever syndrome to experience acute abdominal symptoms and peritonitis.

We present a case of a young man with no prior medical history who arrived at the Emergency department with complaints of sudden abdominal pain, fever, and moderate to significant accumulation of fluid in the abdomen. His blood tests revealed a very low platelet count and an exceptionally high hematocrit value. The presence of expanded dengue viral infection syndrome was suspected, and further testing was requested.