Paediatric atlanto-axial joint tuberculosis with incidental findings on magnetic resonance imaging

A six-year old girl presented with pain and inability to extend the neck for three months. There was history of occasional low-grade fever in this duration, however, she was afebrile at the time of presentation. There was no history of cough, dysphagia or loss of weight. There was no previous trauma or surgery. The child and her parents could not recollect any past foreign body ingestion. Lab investigations revealed mild leukocytosis and raised erythrocyte sedimentation rate.

A lateral view radiograph of the cervical spine performed at another institution showed mild widening of prevertebral space at C1-C2 level with indentation of posterior pharyngeal air column. A chest radiograph showed consolidation involving upper lobe of right lung. She was referred to our institution to rule out the possibility of a retro-pharyngeal abscess.

Plain & contrast enhanced Magnetic Resonance (MR) images showed altered marrow signal abnormality appearing hypointense on T1 and hyperintense on STIR with intense enhancement involving the right side of basi occiput, occipital condyle and  lateral mass of atlas associated with ill-defined, heterogeneously enhancing soft tissue lesion of size 38(AP) x 16(TR) x 21(CC)mm. It was seen to involve the right atlanto-occipital joint and to encase V3 and V4 segments of the right vertebral artery. It appeared isointense on T1 and T2 weighted images with no diffusion restriction of the soft tissue. It was indenting the retropharyngeal space anteriorly with widening of the prevertebral space. There was no subluxation or dislocation of the joints of skull base and cervical spine. Cervical cord was normal.

Multiple enlarged lymph nodes were seen in bilateral posterior triangle of neck, anterior and posterior mediastinum and in the right paratracheal region. Few of these lymph nodes showed central non enhancing areas – suggestive of caseation or necrosis. There was consolidation involving anterior segment of upper lobe of the right lung. No obvious rib or vertebral destruction was seen in the visualized portion of chest. Fine needle aspiration cytology (FNAC), biopsy and culture of cervical lymph nodes was positive for mycobacterium tuberculosis. CT- guided biopsy from the soft tissue at CVJ (craniovertebral junction) revealed caseation necrosis. Anti-tubercular treatment was started following which there was clinical improvement.

Tuberculosis is an infectious disease that is widely spread, approximately 25% of the world population is reported to be infected. It is the second-most common cause of death from infectious disease ( after those due to HIV/AIDS).Tuberculosis of the cranio-vertebral junction (CVJ) can be associated with serious complications such as abscess formation and instability at the CVJ. Compression of the upper cervical cord can lead to bulbar symptoms. Vertebral artery involvement may lead to contralateral hemiparesis or monoparesis. Anti- tubercular treatment is required, and surgery may be needed in the presence of complications. [1] Tuberculosis is common in few endemic countries,although such a presentation in pediatric age group is infrequent. In developed nations, the incidence is higher among immunocompromised patients. Restriction of neck movements can occur due to ligamentous involvement. A lateral cervical spine radiograph is the initial investigation of choice in suspected cases. CT can show bony abnormalities better while MRI is superior for assessment of granuloma, extent of abscess formation, ligamentous and soft tissue involvement. [2] It is preferred in pediatric age group to avoid radiation exposure.

Tuberculous lymphadenitis is the most prevalent form of extra pulmonary tuberculosis in endemic areas. In such regions, children presenting with chronic persistent lymphadenopathy need to be evaluated and FNAC or biopsy from lymph nodes is required to rule out tuberculosis. [3] This represents primary pulmonary tuberculosis. The upper lobes of the lung drain into the ipsilateral paratracheal nodes and the rest of the lungs drain to hilar nodes. Ghon complex is defined as a parenchymal focus of involvement with the enlarged lymph nodes. In immunocompetent children, this caseating lymph nodal focus is followed by calcification with granulomas in lung. In the immunocompromised, there can be widespread hematogenous & lymphatic dissemination of the infection. Progressive primary disease can occur much later, presenting with fibrosis in lung and cavity formation. [4]

Fine needle aspiration from cervical lymph nodes is a non-invasive and cost- effective method for diagnosis[5]. Early diagnosis is vital for prevention of complications. Eliciting history of exposure and screening of other children in the family is also advisable. [2]