Bilateral degenerative suspensory desmitis with acute rupture in a Standardbred colt

A 3-month-old Standardbred colt was examined for acute, bilateral hindlimb swelling and lameness. Serum chemistry demonstrated elevated muscle enzymes (AST, ALT, LDH and CK). Radiographs of the hindlimbs demonstrated intact proximal sesamoid bones that were displaced distally and subluxation of the pastern joints. Ultrasonography of the affected areas revealed large, diffuse hypoechoic areas in the bodies of both hind suspensory ligaments consistent with bilateral rupture. Histology of the lesions was consistent with degenerative suspensory desmitis with acute rupture.