This document discusses peritonitis, which is inflammation of the peritoneum. The peritoneum is the serous membrane that lines the abdominal cavity and covers organs. Peritonitis can be caused by bacterial or fungal infections entering the abdominal cavity from conditions like peritoneal dialysis or fluid buildup from liver disease. It causes symptoms like abdominal pain and swelling, fever, nausea, and vomiting. Treatment involves hospitalization, intravenous antibiotics and fluids to fight the infection and prevent spreading, and sometimes surgery to remove infected tissue.