Performance of abdominal ultrasound for diagnosis of tuberculosis in HIV-infected persons living in Cambodia

Abstract

Background: In resource-limited settings, abdominal ultrasound is often used to assist the diagnosis of tuberculosis (TB) in people with HIV (PLHIV), although data on performance characteristics are missing.

Methods: Cross-sectional study of PLHIV in Cambodia receiving a standardized TB diagnostic evaluation, including history, physical examination, chest radiography, microscopy and culture of various specimens, and abdominal ultrasound. Patients with at least one specimen culture positive for Mycobacterium tuberculosis were classified as having TB.

Results: TB was diagnosed in 37 (18%) of 212 PLHIV. Abdominal ultrasound was abnormal in 15 of 37 (41%) patients with TB compared with 14 of 175 (8%) without TB (P < 0.01). Predictors of TB disease included multiple enlarged (1.2 cm or greater) abdominal lymph nodes on ultrasound (adjusted odds ratio [OR], 6.4; 95% confidence interval [CI], 1.8-22.4), abnormal chest radiography (OR, 6.8; CI, 2.7-17.0), anorexia (OR, 4.6; CI, 1.8-11.7), and CD4 less than 200 cells/mm (OR, 3.3; CI, 1.2-9.1). Having multiple enlarged abdominal lymph nodes on ultrasound was 97.1% (CI, 93.5%-99.1%) specific for TB with a positive likelihood ratio of 11.4 (CI, 4.3-30.3).

Conclusions: Abdominal ultrasound is a useful diagnostic test for TB disease in PLHIV, increasing the posttest probability of TB when multiple enlarged abdominal lymph nodes are visualized. Its wider use may accelerate access to TB treatment, potentially reducing mortality in PLHIV.