A 15-year-old male presents to the pediatric Emergency Department (ED) for evaluation of neck pain for three weeks. The patient is vague as to the development of his symptoms, but his mother reveals patient was assaulted by peers three weeks ago and has had progressively worsening neck pain and stiffness. The patient states symptoms have gotten to the point where he is unable to turn his head but denies fevers, chills, nausea, vomiting, focal weakness, or sensory changes.
This patient was found to have septic arthritis of the atlantooccipital (AO) joint, noted on the CT shown above, with joint space narrowing and erosion (red arrow) of the right AO joint with associated soft tissue swelling and effusion. Seen on the MRI is further confirmation of the findings suggested on CT of septic arthritis, with additional noting of attenuation of the prevertebral space of C2/C3 suggestive of phlegmon, bilateral AO joint arthritis, and involvement of the atlantoaxial joint, all of which can be seen on the above sagittal cut of the MRI, with the most notable being the pre-vertebral phlegmon (red arrow).
Septic arthritis of the facet joints is a rarity, particularly in pediatrics and in the cervical spine; case reports largely describe a lumbar location in elderly adults with predisposing comorbidities (intravenous drug use, diabetes, immunosuppression) for spontaneous infection. There are no published case reports of traumatic, pediatric AO joint septic arthritis. This patient developed septic arthritis following trauma. As with peripheral septic arthritis, the most common cause is hematogenous spread, and even non-penetrating trauma can predispose a joint to infection as likely occurred in this case. Septic arthritis of the facet joints presents similarly to spondylodiscitis, generally with fever, neck or back pain, and elevated inflammatory markers such as CRP/ESR. If left untreated, it can be a dangerous and refractory cause of sepsis that leads to deadly complications such as concomitant epidural access formation. Oftentimes patients are initially misdiagnosed and re-present multiple times as the preferred image modality for diagnosis is MRI which is not always readily available or ordered. In general, treatment generally includes weeks-long courses of intravenous (IV) antibiotics, though this patient was discharged on oral antibiotics after significant symptomatic improvement on IV therapy after four days.
Septic arthritis of the cervical facet joints, namely the AO joint, is a rare cause of neck pain in patients with fever and elevated inflammatory markers, and can present after trauma. Generally, it is hematogenously spread and associated with comorbidities such as diabetes, intravenous drug use, and immunosuppression, it should be considered in patients with refractory symptoms or in which there is strong suspicion as it can have dangerous complications.
The preferred imaging modality for diagnosis is MRI, though CT can be useful in making the diagnosis radiographically. Treatment generally consists of weeks of IV antibiotics.