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Ascites
Symptoms, Signs, and Diagnosis
Nonspecific abdominal discomfort and dyspnea may occur with massive ascites,
but lesser amounts are usually asymptomatic. The diagnosis is made clinically
by detecting shifting dullness on abdominal percussion, though US or CT scan
can detect much smaller amounts of fluid. In advanced cases the belly is taut,
the umbilicus is flat or everted, and a fluid wave can be elicited. Differentiation
from obesity, gaseous distention, pregnancy, or ovarian tumors and other intra-abdominal
masses usually is easily made by clinical examination, but scanning techniques
or diagnostic paracentesis may occasionally be required. In liver disease or
in intra-abdominal disorders, ascites is usually isolated or out of proportion
to peripheral edema; in systemic disease, the reverse is usually true.
If the cause is uncertain, a diagnostic paracentesis should be done. From 50
to 100 mL of fluid is removed and, as clinically indicated, is assessed for
gross appearance, protein content, blood cells, cytology, culture, acid-fast
stain, and/or amylase. In most disorders the fluid is clear and straw-colored.
Turbidity and a high polymorphonuclear cell count ( 300 to 500 cells/µL) suggest infection,
while sanguineous fluid usually signals neoplasm or TB. The rare milky (chylous)
ascites is most common with lymphoma. A protein concentration of  3 gm/dL favors liver disease or a systemic
disorder; a higher protein content suggests an exudative cause (eg, tumor or
infection). However, ascitic protein in cirrhosis occasionally is 4 gm/dL; a serum to ascites albumin concentration
gradient 1.1 gm/dL more reliably indicates portal
hypertensive ascites than does the total protein content of the fluid.
Cirrhotic ascites, especially in alcoholics, occasionally becomes infected without
an apparent source ("spontaneous bacterial peritonitis"). Clinical diagnosis
may be difficult, as the fluid masks signs of peritonitis. Thus, early diagnostic
paracentesis and culture should be done in cirrhotics with unexplained deterioration
and fever, especially if abdominal discomfort is present; presence of 300 to 500 polymorphonuclear cells/µL of fluid justifies therapy.
Survival depends on early, vigorous antibiotic therapy.
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