The role of rapid diagnostic tests in managing adults with pneumonia in low-resource settings

In well-resourced settings the systematic use of rapid diagnostics tests (e.g. pneumococcal urinary antigen test) that define the causal pathogen to direct therapy has not resulted in significantly improved outcomes in adults withpneumonia. The management of pneumonia in many low-resource settings is complicated by a substantial burden of tuberculosis and HIV-associated opportunistic infections, in addition to the usual spectrum of pathogens seenin well-resourced settings. Clinical features alone do not reliably distinguish between these different aetiologiesand physicians often have to treat empirically. Given the limitations in diagnostic laboratory capability present inmost low-resource settings, rapid and point-of-care diagnostic tests could become valuable tools to guide treatment decisions. Pneumococcal and Legionella urinary antigen tests are specific and moderately sensitive, but their utilityin low-resource settings is uncertain. The Xpert MTB/RIF (Cepheid, USA) platform and rapid assays for urinary lipoarabinomannan can substantially speed up tuberculosis diagnosis; the current challenge is to translate this intoearlier treatment and hopefully improve patient outcome. In HIV-infected patients, 1-3-β-D-glucan is a serum marker of Pneumocystis jirovecii infection with excellent sensitivity. Further studies are needed to assess the clinical utilityand cost-effectiveness of these rapid diagnostic assays when they are incorporated into treatment algorithms.

Respiratory infections in HIV-infected adults: epidemiology, clinical features, diagnosis and treatment

PURPOSE OF REVIEW

Using the evidence published over the last 2 years, this review discusses the epidemiology, diagnosis, treatment and prevention of HIV-related pulmonary infections other than mycobacterial disease.

RECENT FINDINGS

Longstanding, vertically acquired and apparently stable HIV infection is associated with significant and symptomatic small airways disease in African adolescents. The use of population-based pneumococcal vaccination in children is changing the severity and serotypes associated with HIV-related pneumococcal disease. Data on the use of blood 1,3,β-D-glucan show it has promise as a rule-out test for Pneumocystis pneumonia (PCP).

SUMMARY

With widespread antiretroviral medication usage, the pattern of HIV-associated pulmonary disease is changing. Whereas opportunistic infections such as PCP still occur in people not using antiretroviral therapy (ART), HIV-related infections are similar to those present in the general population. Chronic lung disease is more prevalent, leading to its own infectious complications. The use of specific immunizations against infections is important, though their precise benefit with concomitant widespread ART and population-based vaccination programmes in the non-HIV community is undetermined.