## Overview Aorto-iliac thrombosis is a progressive vascular condition in which a thrombus forms in the terminal aorta or its iliac branches, reducing blood flow to one or both hind limbs. Clinical signs are typically exercise-induced: hind-limb lameness, weakness, or colic-like behavior that resolves with rest. The affected limb may feel cooler than the opposite limb. The condition is uncommon in well-managed horse populations. ## Causes Historically linked to migrating Strongylus vulgaris larvae that damaged the arterial intima. With modern parasite control the incidence has declined, yet cases still occur, suggesting additional factors such as endothelial trauma, hypercoagulability, or idiopathic vascular disease. ## Diagnosis History of exercise-associated hind-limb lameness that resolves with rest is suggestive. Rectal palpation may reveal a firm thrombus. Transrectal ultrasonography is the most practical confirmatory test. Thermography can demonstrate reduced skin temperature in the affected limb. Nuclear scintigraphy is occasionally used. ## Treatment Medical management with aspirin or other antiplatelet agents and controlled exercise has limited success. Surgical thrombectomy has restored athletic function in selected cases, although the procedure is technically demanding and recurrence is possible. Many horses are retired to pasture. ## Recovery and Prognosis Prognosis for return to previous athletic level is guarded. Some horses improve with rest and medical therapy; others remain limited. Surgical cases have variable outcomes. ## Prevention Effective parasite control reduces the historical risk associated with Strongylus vulgaris. No other specific preventive measures are established.
exercise-induced hindlimb lameness or weakness; cold limb despite sweating elsewhere; colic-like signs during or after work that resolve with rest; weak or absent digital pulses
## Overview Aorto-iliac thrombosis is a progressive vascular condition in which a thrombus forms in the terminal aorta or its iliac branches, reducing blood flow to one or both hind limbs. Clinical signs are typically exercise-induced: hind-limb lameness, weakness, or colic-like behavior that resolves with rest. The affected limb may feel cooler than the opposite limb. The condition is uncommon in well-managed horse populations. ## Causes Historically linked to migrating Strongylus vulgaris larvae that damaged the arterial intima. With modern parasite control the incidence has declined, yet cases still occur, suggesting additional factors such as endothelial trauma, hypercoagulability, or idiopathic vascular disease. ## Diagnosis History of exercise-associated hind-limb lameness that resolves with rest is suggestive. Rectal palpation may reveal a firm thrombus. Transrectal ultrasonography is the most practical confirmatory test. Thermography can demonstrate reduced skin temperature in the affected limb. Nuclear scintigraphy is occasionally used. ## Treatment Medical management with aspirin or other antiplatelet agents and controlled exercise has limited success. Surgical thrombectomy has restored athletic function in selected cases, although the procedure is technically demanding and recurrence is possible. Many horses are retired to pasture. ## Recovery and Prognosis Prognosis for return to previous athletic level is guarded. Some horses improve with rest and medical therapy; others remain limited. Surgical cases have variable outcomes. ## Prevention Effective parasite control reduces the historical risk associated with Strongylus vulgaris. No other specific preventive measures are established.
exercise-induced hindlimb lameness or weakness; cold limb despite sweating elsewhere; colic-like signs during or after work that resolve with rest; weak or absent digital pulses