Histopathology and genotyping in infectious spondylitis of HIV- and HIV+ patients

Mycobacterium Tuberculosis in Spinal Tuberculosis

Even in an era of remarkable medical advances, there is an issue of why tuberculosis remains in the list of disastrous diseases, afflicting humans and causing suffering. There has not been a plausible answer to this, and it has been suggested that clinicians and medical scientists could presently not win the war against the tubercle bacilli. With regards to this issue, based on the authors' own clinical and research experiences, in this review, the available literature was revisited in order to address the raised questions and to provide recent information on characteristics of tubercle bacilli and possible ways to more effectively treat tuberculosis.

HIV-1 and the Mycobacterium tuberculosis granuloma: A systematic review and meta-analysis

Infection with HIV-1 greatly increases the risk of active tuberculosis (TB). Although hypotheses suggest HIV-1 disrupts Mycobacterium tuberculosis (Mtb) granuloma function, few studies have examined this directly. The objective of this study was to determine what evidence exists about the effect HIV-1 co-infection has upon Mtb granulomas. A systematic search of PubMed, Web of Science, and Medline up to 20 March 2015 was conducted, to identify studies comparing Mtb-infected tissue from HIV-1 infected and uninfected persons, or HIV-1 infected persons with stratified peripheral CD4 T cell (pCD4) counts. We summarized findings that focused on how HIV-1 changes granuloma formation, bacterial presence, cellular composition, and cytokine production. Nineteen studies with a combined sample size of 899 persons were included. Although studies frequently were limited by variable or inadequately described definitions of outcomes and analytical methods, HIV-1 was found to be associated with increased bacillary load within Mtb-infected tissue. Reductions in pCD4 counts within co-infected persons associated with both poorer granuloma formation and higher bacterial load. The high degree of heterogeneity among studies combined with experimental limitations made it difficult to conclusively support previously published and prevalent hypotheses about HIV-1/Mtb co-infection granulomas. To elucidate the validity of these hypotheses we have described areas that can be improved in future studies in order to clarify the influence HIV-1 co-infection has upon the Mtb granuloma.

Pathologic approach to spinal cord infections

The pathologic evaluation of spinal cord infections requires comprehensive clinical, radiological, and laboratory correlation, because the histologic findings in acute, chronic, or granulomatous infections rarely provide clues for the specific cause. This brief review focuses on the pathologic mechanisms as well as practical issues in the diagnosis and reporting of infections of the spinal cord. Examples are provided of the common infectious agents and methods for their diagnosis. By necessity, discussion is restricted to the infections of the medulla spinalis proper and its meninges, and not bone or soft tissue infections.

A child presenting with tuberculous spondylitis in a single third cervical vertebra: a case report

INTRODUCTION

Despite a global reduction in tuberculosis, extrapulmonary tuberculosis is increasing. Spinal tuberculosis remains the commonest form of skeletal tuberculosis. Cervical spine involvement is rare but is the most dangerous form because of diagnostic difficulties and serious residual disability. We report a child who had single vertebral involvement of her third cervical vertebra which is extremely rare. To the best of our knowledge isolated third cervical vertebra involvement in a child by tuberculosis has not been reported previously. Difficulties in obtaining material for histology and bacterial culture from this critical location and how the diagnosis was reached despite these challenges are highlighted.

CASE PRESENTATION

A 10-year-old Sinhalese girl developed painful torticollis and 'cries during sleep'. She had received Bacillus Calmette-Guérin vaccine at birth, was well nourished, and had no loss of weight, anorexia or contact with tuberculosis. A plain radiograph of her neck showed a collapsed third cervical vertebra with no disc involvement. Magnetic resonance imaging confirmed isolated destruction of third cervical vertebra associated with prevertebral soft tissue swelling indenting the thecal sac without cord compression. Her chest radiograph was normal. There was peripheral lymphocytosis, elevated erythrocyte sedimentation rate, negative tuberculin (Mantoux) test, and negative QuantiFERON®-TB GoldIn-Tube assay. Invasive procedures to obtain tissue for histology, smear or culture were perceived by parents as dangerous due to surrounding critical structures and consent was denied. The differential diagnosis included spinal tuberculosis and unifocal Langerhan cell histiocytosis. Nocturnal symptoms and the prevertebral collection of soft tissue ('cold abscess') were characteristic of tuberculosis, and nonspecific findings of elevated erythrocyte sedimentation rate and lymphocytosis supported this diagnosis. An incidental finding of a calcified hepatic nodule when evaluating for multifocal histiocytosis was presumed to be tuberculous because schistosomiasis and visceral leishmaniasis were extremely rare in her country of residence, Sri Lanka. Empirical treatment with a 12-month course of antitubercular therapy resulted in clinical recovery and radiological healing. There was no kyphosis or neurological sequel.

CONCLUSIONS

This report highlights to clinicians the value of a high index of suspicion and careful history taking in spinal tuberculosis; and how a combination of nonspecific findings helped reach a clinicoradiological diagnosis.

Immunohistological characterization of spinal TB granulomas from HIV-negative and -positive patients

Tuberculosis (TB) is mainly a disease of the lungs, but Mycobacterium tuberculosis (Mtb) can establish infection in virtually any organ in the body. Rising rates of extrapulmonary (EP) TB have been largely associated with the HIV epidemic, as patients co-infected with HIV show a four-fold higher risk of EPTB. Spinal TB (Pott's Disease), one of the most debilitating extrapulmonary forms of disease, is difficult to diagnose and can cause deformity and/or neurological deficits. This study examined the histopathology and distribution of immune cells within spinal TB lesions and the impact of HIV on pathogenesis. The overall structure of the spinal granulomas resembled that seen in lung lesions from patients with pulmonary TB. Evidence of efficient macrophage activation and differentiation were detectable within organized structures in the spinal tissue, irrespective of HIV status. Interestingly, the granulomatous architecture and macroscopic features were similar in all samples examined, despite a reversal in the ratio of infiltrating CD4 to CD8 T cells in the lesions from HIV-infected patients. This study provides a foundation to understand the mechanism of tissue destruction and disease progression in Spinal TB, enabling the future development of novel therapeutic strategies and diagnostic approaches for this devastating disease.