The presence of a high number of PMN cells (polymorphonuclear leukocytes) in an ascitic tap suggests the presence of inflammation, which is most commonly due to a bacterial infection. In this case, the likely etiology would be spontaneous bacterial peritonitis (SBP). SBP is a common and serious complication of cirrhosis, leading to bacterial infection of the ascitic fluid. Symptoms may include abdominal pain and tenderness, as well as fever and nausea.
Tubercular ascites is caused by tuberculosis, which typically presents with fewer PMN cells and elevated lymphocytes in the ascitic fluid. Malignant ascites is associated with the spread of cancer to the peritoneal cavity, while chylous ascites is a rare type of ascites caused by lymphatic obstruction. Both of these conditions would typically present with fewer PMN cells in the ascitic fluid compared to SBP.