Rapid collapse of the inferior vena cava in a patient with cardiac arrest induced by anaphylactic shock after iodinated contrast medium injection.

Anaphylactic shock to contrast media can progress to cardiac arrest despite appropriate treatment. During anaphylactic shock to contrast media, rapid vasodilation and a massive fluid shift can occur. Here we report a patient who developed cardiac arrest induced by anaphylactic shock to iodinated contrast medium and exhibited rapid collapse of the inferior vena cava (IVC) on enhanced abdominal computed tomography (CT) images. The patient underwent postsurgical unenhanced and contrast-enhanced abdominal CT follow-up of cecum cancer. She had neither allergy nor medical history except for the cancer. She did not complain of any symptoms immediately after completion of the CT. However, she developed anaphylactic shock and pulseless electrical activity cardiac arrest only 2 minutes after finishing the CT despite appropriate treatment. Emergency physicians successfully treated the patient using advanced life support and targeted temperature management. She recovered with good overall and cerebral performance (Overall Performance Category (OPC) 1 and Cerebral Performance Category (CPC) 1). On the contrast-enhanced CT images, she exhibited rapid collapse of the IVC, although it was normal on the unenhanced CT images. The collapsed IVC is a good indicator of hypovolemia in patients with trauma. In this case, we considered that rapid vasodilation and a massive volume shift might have caused the collapsed IVC. This finding suggests the importance of aggressive volume resuscitation as well as epinephrine injection in patients with anaphylactic shock to contrast media. Furthermore, this finding occurred before the onset of clinical symptoms, and there is a possibility that it could be used as an indicator of anaphylactic shock to contrast media.