Castell's sign
Percussion sign for detecting splenomegaly on abdominal exam.
Castell's sign is a medical sign evaluated during abdominal examination to detect enlargement of the spleen. It serves as an alternative to percussion over Traube's space and is considered one of the more reliable physical examination maneuvers for splenomegaly. When used alongside other clinical information, Castell's sign can increase the positive predictive value of the assessment.
Quick Facts
- Sensitivity
- 82%
- Specificity
- 83%
Facts from the source article.
Technique
The patient is placed in the supine position. The examiner percusses the lowest intercostal space, typically the eighth or ninth, in the left anterior axillary line during full expiration and then full inspiration. A change from a resonant note on expiration to a dull note on inspiration constitutes a positive sign. The resonant note on expiration arises from the air-filled stomach or splenic flexure of the colon. With inspiration, the spleen moves inferiorly; if enlarged enough to reach that intercostal space, dullness is appreciated. Limitations include gross splenomegaly or profuse gastric or colonic fluid eliminating the resonant note on expiration, and reduced reliability in obese individuals or depending on post-prandial timing.
Interpretation
Castell's sign is the most sensitive physical examination maneuver for detecting splenomegaly when compared with palpation, Nixon's sign, and Traube's space percussion. In asymptomatic patients with very low clinical suspicion, physical examination alone is unlikely to rule in splenomegaly due to inadequate sensitivity. To achieve a positive predictive value over 90%, the pretest probability must be 70%. A preexamination clinical suspicion greater than 10% is recommended to rule in splenomegaly effectively, though a 10% pretest probability yields a positive predictive value of only 35%. To rule out an enlarged spleen, a pretest probability of 30% or less yields a negative predictive value over 90%. Given the limited physical exam findings for splenomegaly, Castell's sign is a valuable tool in advanced physical diagnosis courses.
More in Symptoms and Signs: Digestive System and Abdomen
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