Imaging of traumatic adrenal injury.

Traumatic adrenal injury is a relatively rare event, reported in 0.15 to 4 % of blunt abdominal trauma cases. The location of the adrenal glands, protected deeply within the retroperitoneum, accounts for the rarity of adrenal trauma. These injuries are unilateral in 75 to 90 % of cases and most commonly afflict the right adrenal gland. While no specific clinical symptoms or signs point directly to adrenal injury, and isolated adrenal injury is rare, the presence of adrenal injury can be an indicator of severe trauma. In fact, mortality rates in series of adrenal injuries range from 7 to 32 %. The most common associated injuries affect the liver, ribs, kidney, or spleen. Three theories of adrenal injury from blunt trauma have been proposed: (1) acute rise in intra-adrenal venous pressure due to compression of the IVC during impact, (2) crushing between the spine and surrounding organs, and (3) deceleration forces shearing the small adrenal arterioles. The most common imaging features include a 2-3-cm oval hematoma, irregular hemorrhage obliterating the adrenal gland, periadrenal hemorrhage or fat stranding, and uniform adrenal swelling with increased attenuation. The differential diagnosis of adrenal abnormalities on trauma CT includes adenoma, carcinoma, myelolipoma, metastases, pheochromocytoma, and tuberculosis. Preexisting adrenal disorders can predispose the adrenal to injury with minor trauma. Most adrenal traumatic injuries are managed conservatively.