Discovertebral (Andersson) lesions of the spine in ankylosing spondylitis revisited

A well-known complication in patients with ankylosing spondylitis (AS) is the development of localised vertebral or discovertebral lesions of the spine, which was first described by Andersson in 1937. Since then, many different terms are used in literature to refer to these localised lesions of the spine, including the eponym ‘Andersson lesion’ (AL). The use of different terms reflects an ongoing debate on the exact aetiology of the AL. In the current study, we performed an extensive review of the literature in order to align communication on aetiology, diagnosis and management between treating physicians. AL may result from inflammation or (stress-) fractures of the complete ankylosed spine. There is no evidence for an infectious origin. Regardless of the exact aetiology, a final common pathway exists, in which mechanical stresses prevent the lesion from fusion and provoke the development of pseudarthrosis. The diagnosis of AL is established on conventional radiography, but computed tomography and magnetic resonance imaging both provide additional information. There is no indication for a diagnostic biopsy. Surgical instrumentation and fusion is considered the principle management in symptomatic AL that fails to resolve from a conservative treatment. We advise to use the term Andersson lesion for these spinal lesions in patients with AS

The benefits and risks of bacille Calmette-Guérin vaccination among infants at high risk for both tuberculosis and severe combined immunodeficiency: assessment by Markov model

BACKGROUND: Bacille Calmette-Guérin (BCG) vaccine is given to Canadian Aboriginal neonates in selected communities. Severe reactions and deaths associated with BCG have been reported among infants born with immunodeficiency syndromes. The main objective of this study was to estimate threshold values for severe combined immunodeficiency (SCID) incidence, above which BCG is associated with greater risk than benefit. METHODS: A Markov model was developed to simulate the natural histories of tuberculosis (TB) and SCID in children from birth to 14 years. The annual risk of tuberculous infection (ARI) and SCID incidence were varied in analyses. The model compared a scenario of no vaccination to intervention with BCG. Appropriate variability and uncertainty analyses were conducted. Outcomes included TB incidence and quality-adjusted life years (QALYs). RESULTS: In sensitivity analyses, QALYs were lower among vaccinated infants if the ARI was 0.1% and the rate of SCID was higher than 4.2 per 100,000. Assuming an ARI of 1%, this threshold increased to 41 per 100,000. In uncertainty analyses (Monte Carlo simulations) which assumed an ARI of 0.1%, QALYs were not significantly increased by BCG unless SCID incidence is 0. With this ARI, QALYs were significantly decreased among vaccinated children if SCID incidence exceeds 23 per 100,000. BCG is associated with a significant increase in QALYs if the ARI is 1%, and SCID incidence is below 5 per 100,000. CONCLUSION: The possibility that Canadian Aboriginal children are at increased risk for SCID has serious implications for continued BCG use in this population. In this context, enhanced TB Control – including early detection and treatment of infection – may be a safer, more effective alternative

Drug Resistant Mycobacterium tuberculosis of the Beijing Genotype Does Not Spread in Sweden

BACKGROUND: Drug resistant (DR) and multi-drug resistant (MDR) tuberculosis (TB) is increasing worldwide. In some parts of the world 10% or more of new TB cases are MDR. The Beijing genotype is a distinct genetic lineage of Mycobacterium tuberculosis, which is distributed worldwide, and has caused large outbreaks of MDR-TB. It has been proposed that certain lineages of M. tuberculosis, such as the Beijing lineage, may have specific adaptive advantages. We have investigated the presence and transmission of DR Beijing strains in the Swedish population. METHODOLOGY/PRINCIPAL FINDINGS: All DR M. tuberculosis complex isolates between 1994 and 2008 were studied. Isolates that were of Beijing genotype were investigated for specific resistance mutations and phylogenetic markers. Seventy (13%) of 536 DR strains were of Beijing genotype. The majority of the patients with Beijing strains were foreign born, and their country of origin reflects the countries where the Beijing genotype is most prevalent. Multidrug-resistance was significantly more common in Beijing strains than in non-Beijing strains. There was a correlation between the Beijing genotype and specific resistance mutations in the katG gene, the mabA-inhA-promotor and the rpoB gene. By a combined use of RD deletions, spoligotyping, IS1547, mutT gene polymorphism and Rv3135 gene analysis the Beijing strains could be divided into 11 genomic sublineages. Of the patients with Beijing strains 28 (41%) were found in altogether 10 clusters (2-5 per cluster), as defined by RFLP IS6110, while 52% of the patients with non-Beijing strains were in clusters. By 24 loci MIRU-VNTR 31 (45%) of the patients with Beijing strains were found in altogether 7 clusters (2-11 per cluster). Contact tracing established possible epidemiological linkage between only two patients with Beijing strains. CONCLUSIONS/SIGNIFICANCE: Although extensive outbreaks with non-Beijing TB strains have occurred in Sweden, Beijing strains have not taken hold, in spite of the proximity to high prevalence countries such as Russia and the Baltic countries. The Beijing sublineages so far introduced in Sweden may not be adapted to spread in the Scandinavian population