A poor outcome in non-occlusive thrombo-embolic limb ischaemia related to the dislocation of mural thrombus from an abdominal aortic aneurysm.

BACKGROUND: Acute thrombosis of an abdominal aortic aneurysm with acute limb ischaemia is an unusual complication and is associated with high mortality. Dislocation of the intrasaccular mural thrombus could be one of the mechanisms. For the most part, acute limb ischaemia presents with absent pulses, compatible with the clinical findings, which include pain, paraesthesia, and paralysis. Herein, we report a rare condition with detectable distal pulses in advanced limb ischaemia due to poor perfusion caused by the dislocation of mural thrombus from an abdominal aortic aneurysm.

CASE PRESENTATION: A 74-year-old male patient with underlying hypertension and chronic renal disease presented at the emergency room with bilateral lower limb paralysis after falling on his back in the bathroom an hour prior. He reported numbness and weakness of his lower limbs, which was gradually worsening, over the past week. Physical examination showed cyanotic mottling of the lower limbs with paralysis. However, the dorsalis pedis pulse was intact. Computed tomography angiography showed a 7.3 cm abdominal aortic aneurysm containing highly irregular mural thrombus in the early phase, with slow perfusion of the contrast medium in the arteries below the bifurcation during the delayed phase. After traumatic spinal injury was excluded, an emergent endovascular aneurysm repair was performed. Although vital signs were initially stable post-surgery, both lower limbs were still paralysed and did not improve. He then experienced reperfusion injury with metabolic acidosis. There was no urine output despite intravenous hydration. Laboratory data included potassium 7.7 mEq/L, lactate 110 mg/dL, white blood cells 23,700/uL, and myoglobin 46,590 ng/mL. Even under critical medical care and continuous venovenous hemofiltration, his hemodynamic status worsened. He developed hypotension and needed endotracheal intubation because of loss of consciousness and respiratory failure. The patient finally died due to ventricular tachycardia even after several rounds of cardiopulmonary resuscitation with cardioversion.

CONCLUSION: The unusual clinical presentation of detectable lower limb pulses in advanced limb ischaemia showed that poor blood perfusion related to dislocation of mural thrombus in abdominal aortic aneurysm might mislead clinicians and delay accurate diagnosis and treatment.