Prehn's sign

The Prehn sign is a differential diagnostic characters for the differentiation of acute scrotum. With it, one can distinguish between testicular torsion and inflammation of the epididymis ( epididymitis ). In the classical case, the testicular pain decreased in a epididymitis by raising the painful testicle or no pain acceptance in the case of testicular torsion. This process was described by the American Urological DT Prehn in the 20th century.

The Prehn sign is not conclusive, so that, in general, further diagnostic measures are necessary (Doppler sonography). Because of the narrow time window ( organ loss within about six hours) is surgically exposed in unclear cases the testicles.

Implementation

The examiner lifts the affected testicle.

• The pain decrease with increase of the testis: The Prehn 's sign is positive, indicating an orchitis or epididymitis.
• The pain increases with increase in the testicle or remain unchanged: The Prehn sign is negative. This is the case for example with a testicular torsion.