Subarachnoid Contrast Hyperdensity Following Pelvic Trauma Mimicking Diffuse Subarachnoid Hemorrhage

Abstract

We present a case of a 54-year-old male who was involved in a motorcycle accident. His head computed tomography (CT) scan on arrival at our Level 1 institution was positive for hyperdensity suspicious for subarachnoid hemorrhage (SAH). Spine CT showed anterior compression fractures of T7-T9 vertebral bodies along with the presence of contrast within the subarachnoid space in the thoracic and lumbar spine, raising suspicion for a dural tear. CT of the chest, abdomen, and pelvis revealed open book pelvic fracture, left sacral ala fracture extending into the left sacroiliac joint and S1 neural foramen, coccygeal fracture, and extraperitoneal bladder rupture. This rare case report highlights the possibility of a spinal meningeal tear in severe pelvic trauma with concomitant bladder injury as a pathway of contrast entry into the normally impermeable cerebrospinal fluid (CSF) space mimicking traumatic subarachnoid hemorrhage.

Keywords: contrast hyperdensity; dural tear; pelvic trauma; subarachnoid hemorrhage.

Figure 1. Tile Type C1 pelvic fracture (left); posterior pelvic disruption (right)

Figure 2. Extravasation on the left side of the bladder neck (arrow)

Figure 3. Contrast in the extra-peritoneal space (arrow, top left); contrast tracking to the space around the site of the bladder rupture in the retroperitoneum at the level of the sacrum (arrow, top right); contrast entering the lumbar subarachnoid space (arrow, bottom left); contrast ascending along the subarachnoid space due to the dural tear (arrow, bottom right)

Figure 4. Initial head CT on presentation showing no subarachnoid hyperdensity (left); six-hour interval head CT showing intraventricular hyperdensity (arrow, right)

CT: computed tomography

Figure 5. CT of the thoracolumbar spine with coronal and sagittal reconstructions

CT: computed tomography