Cervical Vertebral Osteomyelitis in a 9-Year-Old Girl

A 9-year-old girl was transferred from an outside hospital because of neck pain with associated fever. One month earlier, she sought treatment at a local emergency department (ED) and a neck sprain was diagnosed. At that time, a peripheral white blood cell (WBC) count was normal and head and neck CT scans showed fluid in the right maxillary sinus. Ibuprofen, as needed, was prescribed, and follow-up with an orthopedic surgeon was recommended but not done. One week before presentation, she returned to the ED with worsening neck pain and fever (temperature up to 39.1ºC [102.4ºF]). The WBC count was elevated to 20,400/µL, with 92% neutrophils. A CT scan without contrast showed findings consistent with right maxillary sinusitis. She was given intravenous ceftriaxone and discharged home with oral amoxicillin/clavulanate.

The neck pain and fever persisted, and she returned to the ED a third time. At this visit, the WBC count had dropped to 10,800/µL; the C-reactive protein (CRP) level and erythrocyte sedimentation rate (ESR) were 12 mg/dL and 119 mm/h, respectively. She was hospitalized and given another dose of intravenous ceftriaxone. MRI scans with contrast showed edema and abnormal enhancement in the left lateral mass of the first cervical vertebral body as well as the skull base, including the clivus, the occipital condyles, and adjacent occipital bone (Figure). There was also septic arthritis of the joint space between C1 and C2.

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At the time of transfer, the child described the pain as 6 or 7 out of 10 and “like someone is punching me.” The pain was absent at rest; it increased with movement and radiated from the ears to the base of the neck. There was no history of neck trauma.

On examination, the child was afebrile but visibly distressed; she sat rigid and motionless in the bed. Active range of motion of the neck was decreased because of pain. There was tender right anterior cervical lymphadenopathy and tenderness to palpation at the level of the C1-C2 vertebrae. The rest of the spine was nontender. The trapezius muscle was tender to palpation bilaterally. Neurological findings were normal.

Radiographs of the cervical spine showed a correctable 4-mm atlantodental gap, suggestive of C1-C2 instability. The neck was immobilized in a cervical collar. Results of a purified protein derivative test were negative.

The patient received intravenous vancomycin for 7 days. Because blood cultures at the local hospital showed no growth and she had defervesced and remained afebrile after initial antibiotic therapy, vancomycin was switched to ceftriaxone to cover Staphylococcus aureus, which was presumptively sensitive to ceftriaxone. A peripherally-inserted central catheter was placed and the child was discharged home to receive a month of antibiotic therapy. At follow-up 1 month later, she had no fever or pain and the CRP level had dropped to 0.1 mg/dL

VERTEBRAL OSTEOMYELITIS: AN OVERVIEW

Vertebral osteomyelitis is rare in children, comprising only 1% to 2% of all pediatric cases of osteomyelitis.^1,2 The condition generally involves the epiphyses of long bones in children younger than 18 months and the metaphyses of long bones in older children. It occurs less frequently in short and flat bones, such as the scapula, ribs, calcaneus, metatarsals, carpals, pelvis, and skull.² In one series of 14 children with a discharge diagnosis of vertebral osteomyelitis, only 1 (7%) had involvement of the cervical vertebrae.¹ The mean age of children with vertebral osteomyelitis was 7.5 years (range, 2 to 13 years). In another series of 253 children and adults with vertebral osteomyelitis, only 11% of cases involved the cervical spine.³

Possible origin. Several mechanisms of vertebral osteomyelitis have been theorized, including hematogenous dissemination, contiguous spread from a nearby infection, and direct inoculation. Most pediatric cases of osteomyelitis result from hematogenous spread.⁴ In older children, vertebral osteomyelitis is thought to occur when the causative species lodge in low-flow, end-organ vessels adjacent to the subchondral plate region; this usually limits infection to one vertebra.¹ However, neonates and infants with cervical vertebral osteomyelitis may have involvement of multiple vertebrae, possibly because blood flow through the intervertebral discs is more significant in these patients.²

Signs and symptoms. Clinicians should consider the diagnosis of cervical vertebral osteomyelitis in a child with the following:

•Neck pain.

•Fever.

•One or more: swelling, erythema, joint tenderness, or decreased range of neck motion.

Organism identification. The organism identified most often is S aureus, which occurs in up to 50% to 90% of cases of vertebral osteomyelitis in otherwise healthy children older than 5 years.^2,5 Other less common causes include Salmonella species, Streptococcus pneumoniae, Pseudomonas aeruginosa, Kingella kingae, Mycobacterium tuberculosis (Pott disease), and Bartonella henselae.^2,6 The precise cause of vertebral osteomyelitis remains unknown in up to a third or more of cases.²

Identifying the causative organism can help guide the selection and duration of antibiotic therapy. Experts have recommended obtaining cultures of blood and of an aspirate from the involved site. In this patient, aspirating the bone was deemed too risky given the location of the infection and a causative organism was not identified.

Diagnostic imaging. Imaging is recommended. For vertebral osteomyelitis in the neck, lateral radiographs often detect characteristic prevertebral soft-tissue swelling thought to be caused by edema secondary to infection or a nearby abscess.⁴ MRI is highly accurate for detecting vertebral osteomyelitis (96% sensitive, 93% specific).⁷ MRI scans show edema that appears hypointense on T1-weighted images and hyperintense on T2-weighted images. Abnormal enhancement is seen on post-contrast imaging.

Special MRI techniques, such as short-term inversion recovery and chemical fat-saturated post-contrast images, may help to delineate bone marrow involvement or the presence of an epidural abscess.⁶

Management. Whenever possible, the choice of antibiotic therapy is based on the blood and bone aspirate culture and sensitivity results. When S aureus or a gram-negative rod is identified, it is recommended that intravenous antibiotic therapy be administered for a minimum of 21 days and that normalization of the ESR be tracked.⁷ Improvement in a patient’s pain or range of motion can be helpful in determining the duration of intravenous antibiotic therapy.⁵ Return of an elevated WBC count, ESR, and CRP level to normal values suggests a good clinical response.^7,8

Complications. If left untreated, cervical vertebral osteomyelitis can potentially result in permanent neurological deficits, deformities of the spine, and even death.