MR imaging of fatal atlantoaxial dislocation caused by retropharyngeal abscess.

A 9-month-old girl was evaluated in our emergency room for 1 03°F fever and decreased activity. Three weeks earlier, at another hospital , the patient had been treated with antibiotics and skin grafting for secondand third-degree scald burns. On the current admission, a nonfluctuant neck swelling was noted, but otherwise the results of the physical and neurologic examinations were normal. WBC was 21 ,600/J.tl , and cultures of CSF and blood grew Staphylococcus aureus . After admission, a gallium-57 citrate scan showed increased uptake of radionuclide in the cervical region, left shoulder, and right elbow, consistent with multifocal osteomyelitis. Routine cervical radiographs were not obtained. Emergency MR imaging of the head and upper cervical spine showed a large retropharyngeal soft-tissue mass consistent with an abscess (Fig . 1 ). The mass extended intracranially into the epidural space immediately anterior to the brainstem. Dislocation of the C1-C2 articulation and marked compression of the cervical spinal cord also were seen. During MR imaging, the patient suddenly stopped breathing and could not be resuscitated . Autopsy showed evidence of systemicS. aureus septicemia and of spinal cord compression associated with atlantoaxial subluxation caused by a large retropharyngeal abscess.