Definition: The presence of an abnormal accumulation of fluid within the peritoneal cavity. Detectable when over 500ml. Contains high amount of proteins and electrolytes.
Causes: Most commonly caused by obstruction in the hepatic-portal circulation in particular cirrhosis of the liver. The ascetic fluid escapes from the abdominal vessels such as the lymphatics and veins.
Other causes of ascites include; congestive heart failure, neoplastic conditions, kidney problems such as nephrosis and proteinuria, peritonitis. Ascites can also be caused by abdominal infections such as parasites and funguses.
Examination: Observation: When a large amount of ascetic fluid is presence the abdomen looks uniformly distended. Palpation: generalised gentle palpation will show evidence of abnormal swelling but the following tests are ore diagnostic. Percussion: In the supine position there will be dullness around the flanges and resonance around the umbilical region.
Shifting dullness test: place the patient on their side and after 30 seconds perform percussion. The ascetic fluid will shift with gravity towards the side they are lying on. Percussion will produce dull sounds on the lower part of the abdomen and resonant sounds on the top side. Other tests include fluid thrill and fluid tap.