Castell's sign

Castell's sign is a medical sign assessed to evaluate splenomegaly and typically part of an abdominal examination. It is an alternative physical examination maneuver to percussion over Traube's space.

Splenomegaly, although associated with numerous diseases, remains one of the more elusive physical exam findings in the abdomen. Conditions such as infectious mononucleosis, thalassemia, and cirrhotic liver disease may all involve splenomegaly and as a result, the search for a reliable sign associated with this condition has been sought for generations. Currently, several such signs of splenomegaly exist, all of whose utility has been debated in medical literature. The presence or absence of splenomegaly, however, can be reliably appreciated on physical exam using Castell's sign in conjunction with other clinical information, increasing the positive predictive value of the test. When used in a decision-making rubric, Castell's sign becomes a valuable part of deciding whether to pursue further imaging.

Castell's method involves first placing the patient in the supine position. With the patient in full inspiration and then full expiration, percuss the area of the lowest intercostal space (eighth or ninth) in the left anterior axillary line. If the note changes from resonant on full expiration to dull on full inspiration, the sign is regarded as positive. The resonant note heard upon full expiration is likely to be due to the air-filled stomach or splenic flexure of the colon. When the patient inspires, the spleen moves inferiorly along the posterolateral abdominal wall. If the spleen is enlarged enough that the inferior pole reaches the eighth or ninth intercostal space, a dull percussion note will be appreciated, indicating splenomegaly.

Some limitations, however, were also reported by Castell in his original paper. First the presence of gross splenomegaly or profuse fluid in the stomach or colon may lead to the absence of a resonant percussion note on full expiration. Also, later articles have criticized the maneuver's reliability as befalling to more obese individuals and the amount of time the patient is post-prandial.

The 1993 systematic review by the Rational Clinical Examination found that Castell's sign was the most sensitive physical examination maneuver for detecting splenomegaly when comparing palpation, Nixon's sign (another percussion sign), and Traube's space percussion:

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