Detection of splenic microabscesses with ultrasound as a marker for extrapulmonary tuberculosis in patients with HIV : a systematic review

Background. In 2015, 1.2 million new cases of tuberculosis (TB) were diagnosed in patients with HIV. Diagnostic limitations and resource shortages in endemic areas can delay diagnosis and treatment, particularly with extrapulmonary TB (EPTB). Research suggests that ultrasound can identify splenic microabscesses caused by EPTB, but data are limited on the frequency of this finding in patients with culture-proven EPTB.Objectives. To estimate the frequency of splenic EPTB microabscesses detected with ultrasound in patients with HIV and TB co-infection.Methods. Studies published in six major databases as of November 2017 were systematically reviewed based on the PRISMA guidelines. Cohen’s kappa test was used to determine inter-rater agreement. Articles included for data abstraction passed the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) evaluation. Freeman-Tukey transformation was used to calculate weighted proportions. Heterogeneity was evaluated by Forest plot and I2 calculation.Results. After abstract screening, article review and QUADAS-2 evaluation, five studies were selected for data extraction. A total of 774 patients in these studies were infected with HIV. Splenic lesions were seen with ultrasound in 21.0% of patients with HIV (95% confidence interval (CI) 10.6 - 33.8). TB diagnosed by culture, biopsy, smear, or molecular methods was found to be the cause of 88.3% (95% CI 72.3 - 97.9) of splenic microabscesses seen on ultrasound in patients with HIV. Conclusions. Ultrasound evaluation of the spleen in patients with HIV and symptoms suggestive of TB in endemic regions is a viable diagnostic adjunct. Ultrasound detection of splenic microabscesses in HIV patients is probably sufficient indication to initiate TB treatment prior to obtaining culture data. Strong conclusions cannot be drawn owing to the high heterogeneity of this small number of studies.