Abnormal fluid can accumulate in the peritoneal cavity.
Fluid accumulation in the peritoneum reflects an imbalance between fluid formation and reabsorption of such fluid altered by a pathologic process.
Fluid in the peritoneal cavity is referred to as ascites and is due to increased hydrstatic pressure in the systemic circulation, increased peritoneal capillary permeability, decreased plasma oncotic pressure or decreased fluid reabsorption by lymphatics.
Causes ranges from disorders and diseases that directly involve the peritoneum such as bacterial peritonitis, to indirect processes such as cirrhosis, congestive heart failure, Budd-Chiari syndrome, hypoalbuminemia, myxedema, ovarian disease, pancreatic disease, and chylous ascites.
Effusions with transudate include cirrhosis, congestive heart failure, and hypoproteinemia.
Effusions associated with exudates include primary or secondary peritonitis, malignancies, trauma, infarcted bowel and pancreatitis.
Transudates are usually clear and yellow.
Exudates are usually cloudy or turbid due to the presence of leukocytes, proteiuns, and occasionally microorganisms.
Ascites evaluation includes gross inspection, cell count, cell differentiation, cytology, analysis of protein level, LDH level and microbiology culture.
Peritoneal fluid that is bloody may be seen in trauma patients, and patients with ruptured spleen or liver, intestinal infarction, pancreatitis or malignancies.
Green colored ascites may result from the presence of bile such as may be seen in patients with perforated gall bladders, intestines or duodenal ulcers, cholecystitis, or acute pancreatitis.
Chylous ascites may be caused by: obstruction of the lymph flow by external pressure resulting in leakage from dilated subserosal lymphatics into the peritoneal cavity, exudation of lymph via the walls of retroperitoneal vessels lacking valves into the peritoneal cavity , and from thoracic duct obstruction causing leakage of chyle.