Diffuse brucellar cervical spondylodiscitis

Clinical History

A previously healthy 23-year-old male patient with sub-acute cervical pain increasing with mobility and accompanied with headache, myalgia and fever. On physical examination he had high body temperature and neck stiffness without focal neurological signs. Laboratory tests demonstrated anaemia, elevated C-reactive protein and erythrocyte sedimentation rate. There was a history of cottage cheese consumption.

Imaging Findings

CT of the cervical spine showed body platform irregularities at C2 inferior endplate, prevertebral soft tissue mass likely corresponding to an abscess and a soft tissue anterior epidural mass.
MRI depicted better the C2-C3 vertebral disk involvement and the associated pre-vertebral/epidural/foraminal soft tissue mass exerting anterior spinal cord compression. Regarding the clinical history and the imaging findings, the diagnosis of pyogenic, tuberculous or brucellar spondylodiscitis was considered.
Pharyngeal aspirative puncture demonstrated purulent material. Serologic tests and two blood cultures were positive for Brucella mellitensis. Lumbar puncture was normal and thus the patient started long course double antibiotherapy with doxycycline and rifampicin.
Follow-up MRI performed three-months after demonstrated significant radiologic improvement, with complete resolution of the cervical epidural and prevertebral soft tissue component.

Discussion

Brucellosis is a multisystemic infection caused by gram-negative bacilli of the genus Brucella and musculoskeletal involvement is the most common complication of this zoonosis [1].
In children, peripheral artheritis is the predominant form, with predilection for large weight-bearing joints [2].
In adults, it usually affects the lumbar spine (although any segment may be involved) and the clinical picture includes fever, inflammatory back pain and neurological deficits [3].
There are two types of spinal infection: focal and diffuse. The focal type typically involves the anterior aspect of the superior endplate (the more vascularised region, where the micro-organisms enter by a haematogenous route) and imaging features include bone erosion or sclerosis, peripheral vacuum phenomenon and anterior osteophytosis (parrot´s beak). Depending on host factor and pathogen virulence, the infection may progress to the entire vertebral body, the intervertebral disc and the adjacent vertebral elements, configuring a diffuse spinal infection [4]. In a minority of cases, the epidural and prevertebral compartments may also be involved. MRI is the most specific technique to detect this complication that is usually a result of direct extension of the spondylodiskitis [4, 5]. Although rarely, the soft tissue component has also been described in the absence of osteomyelitis in the context of spinal brucellosis [6].
In the context of a necrotic/cystic lesion in the different spaces of the head and neck region, diffusion weighted imaging (DWI) is helpful in establishing the differential diagnosis, typically showing hyperintensity in infective lesions and hypointensity in tumoural masses [6].
The aetiologic diagnosis is achieved in 95% of cases combining the use of blood cultures with two serologic tests (standard tube agglutination test and Coombs test). Indeed, vertebral biopsy is rarely needed to achieve the final correct diagnosis [3].
Classically, pre-vertebral and epidural masses in the context of Brucella infection were treated surgically. More recently, in cases where neurological focal deficits are absent, long antibiotic therapy with close observation is the preferred option, even when epidural/paravertebral extension is present. Good clinical outcome is usually reported in association with the conservative management, as seen in our case [7, 8].
As imaging features of this condition are not pathognomonic, high index of suspicion is needed in non-endemic countries to avoid late diagnosis. All patients with fever and rheumatologic complaints should undergo specific serological and MRI evaluation in order to rule out Brucella infection [5, 7, 9].

Differential Diagnosis List

Final Diagnosis

Brucellar cervical spondylodiscitis with prevertebral and epidural component

URL:	https://www.eurorad.org/case/10739
DOI:	10.1594/EURORAD/CASE.10739
ISSN:	1563-4086