Intracavernous carotid artery aneurysms (ICCAs) are rarely associated with life-threatening complications. We describe a 55-year-old woman who, after the rupture of an intracavernous carotid artery aneurysm, presented with a contralateral cavernous sinus syndrome and severe posterior fossa and spinal cord symptoms. Following parent artery occlusion, thrombosis of the posterior fossa and spinal cord veins caused a progressive worsening of the neurological status to a "locked-in" state. The patient fully recovered with anticoagulation therapy. Comprehension of the pathophysiological mechanism associated with the rupture of ICCA and early diagnosis of the related symptoms are essential in order to plan a correct treatment that includes the management of the aneurysm rupture and of possible complications related to venous thrombosis.