Assessment of Shifting Dullness in Ascites

Technique for Assessing Shifting Dullness

The American Association for the Study of Liver Diseases recommends that to assess for shifting dullness, a patient's flanks should be percussed while they are supine, the dullness-tympany interface marked, then the patient should roll to the opposite side and the movement of dullness to the dependent side observed 1, 2
The initial assessment should begin with the patient in a supine position, as recommended by the American College of Gastroenterology 3, 4
Inspection of the abdomen for fullness or bulging, which may suggest the presence of ascites, is a crucial step, according to the American Association for the Study of Liver Diseases 1, 2
Approximately 1,500 mL of fluid must be present before flank dullness is detectable, as stated by the American Gastroenterological Association 3, 1

Shifting dullness has 83% sensitivity and 56% specificity in detecting ascites, as reported by the American Association for the Study of Liver Diseases 1, 2
If no flank dullness is present in the supine position, the patient has less than a 10% chance of having ascites, according to the American College of Gastroenterology 3, 1

In obese patients, physical examination for ascites is challenging, and abdominal ultrasound may be required to confirm the presence of fluid, as suggested by the American Association for the Study of Liver Diseases 1, 2
Approximately 75-85% of patients with ascites have cirrhosis as the underlying cause, as reported by the American Association for the Study of Liver Diseases 4, 5
Jugular venous distension should be assessed, as its presence suggests cardiac rather than hepatic causes of ascites, according to the American Heart Association 3, 1
Brain natriuretic peptide (BNP) levels can help distinguish between cardiac ascites and cirrhotic ascites, as stated by the American Association for the Study of Liver Diseases 1, 2