Shifting dullness

Shifting dullness is a medical sign used in the physical examination of a patient to detect the presence of ascites. Ascites is the abnormal accumulation of fluid in the abdominal cavity, often seen in conditions such as liver cirrhosis and heart failure. Shifting dullness is a method used by healthcare professionals to identify ascites when other methods, such as imaging, are not available or not feasible.

Procedure

The procedure for detecting shifting dullness involves the patient lying down on their back, or in the supine position. The healthcare professional will then percuss, or tap, the patient's abdomen from one side to the other. In a patient without ascites, the sound produced by this tapping will be resonant throughout due to the presence of air-filled intestines. However, in a patient with ascites, the sound will change from resonant to dull as the examiner moves from the gas-filled intestines to the fluid-filled area.

Interpretation

The presence of shifting dullness is considered a positive sign for ascites. However, it is not a definitive diagnostic tool. Other tests, such as ultrasound or computed tomography (CT) scan, may be needed to confirm the diagnosis and determine the volume of fluid present. It is also important to note that shifting dullness can be absent in cases of small volume ascites.

Limitations

While shifting dullness is a useful sign in the detection of ascites, it has its limitations. It is less accurate in obese patients, as the increased amount of fat can mimic the sound changes associated with fluid. It is also less reliable in patients with chronic ascites, as the fluid may be encapsulated and not free to move with changes in position.

See also

• Abdominal examination
• Fluid wave test
• Liver cirrhosis
• Heart failure