Point-of-care ultrasound for tuberculosis and HIV-revisiting the focused assessment with sonography for HIV-associated tuberculosis (FASH) protocol and its differential diagnoses

Background: The 'Focused assessment with sonography for HIV -associated tuberculosis' (FASH) protocol has been applied and researched for over a decade in HIV-infected patients with suspected extrapulmonary tuberculosis. Interpretation of target FASH features may be challenging as they can also indicate alternative opportunistic diseases. Objectives: The primary aim of the review was summarizing the accumulated evidence on the diagnostic accuracy of the FASH protocol including description of diagnoses of target FASH features. Sources: Literature was searched using PubMed, Google Scholar, and publications referencing the original FASH publications; data from identified studies were compiled with data from studies identified by a preceding Cochrane review. A meta-analysis was performed based on a generalized linearized mixed model. Data on differential diagnoses were compiled by literature review and retrospective evaluation of clinical data. Content: We identified ten studies; abdominal target FASH features were most studied. Sensitivity and specificity estimates were 39% (95% CI 25-54) and 89% (95% CI 83-96) for enlarged lymph nodes (ten studies), and 30% (95% CI 16-45%) and 93% (95% CI 89-98%) for hypoechoic spleen lesions (eight studies). In people living with HIV differential diagnoses of target FASH features are multiple and primarily include other opportunistic infections and malignancies such as non-tuberculous mycobacterial infection, bacillary angiomatosis, hepato-splenic brucellosis, meliodiosis, visceral leishmaniasis, invasive fungal infections, and lymphoma as well as Kaposi sarcoma. Ultrasound-guided diagnostic sampling may assist obtention of a definitive diagnosis. Implications: On the basis of current evidence, although limited by methodology, and personal experience, we recommend basic ultrasound training, including the FASH protocol and ultrasound-guided diagnostic interventions, for all healthcare providers working with people living with HIV in resourcelimited settings. Sabine Belard, Clin Microbiol Infect 2024;30:320 (c) 2023 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.