Think TB! Is the diagnosis of pulmonary tuberculosis delayed by the use of antibiotics?

SETTING: Effective tuberculosis (TB) control requires prompt diagnosis of infectious cases through early suspicion of pulmonary TB in all subjects with suspected respiratory infection. OBJECTIVE: To test our hypothesis that prior antibiotic treatment for presumed bacterial infection leads to a delay in diagnosing TB in a European country with low TB incidence. DESIGN: Adults with culture-confirmed pulmonary TB at a single metropolitan centre were assessed for the impact of any previous antibiotic treatment on symptoms and the time to starting specific anti-tuberculosis treatment. RESULTS: Of 83 patients, 42 (51%) received antibiotics prior to TB diagnosis, with symptomatic improvement reported in 20 of the 42 (48%) patients. This was unrelated to specific drug class. Although the median time to diagnosis in subjects receiving antibiotics was prolonged (P=0.001), this was not predicted by treatment response. In 94% of cases, the initial chest radiograph was suggestive of TB infection. CONCLUSION: Patients receiving antibiotics prior to TB confirmation experience a process-related delay in starting treatment. To minimise the risk of ongoing TB transmission, we propose that clinicians should include TB in their differential diagnosis and initiate simple, TB-focused investigations early on in the diagnostic process.

Paradoxical reactions during tuberculosis treatment in patients with and without HIV co-infection.

BACKGROUND: It has been suggested that deterioration of tuberculosis (TB) during appropriate treatment, termed a paradoxical reaction (PR), is more common and severe in HIV positive individuals on highly active antiretroviral therapy (HAART). METHOD: A study was undertaken to determine the frequency of PR and its associated features in a population of HIV+TB+ patients and a similar sized group of HIV-TB+ individuals. RESULTS: PR occurred in 28% of 50 HIV+TB+ patients and 10% of 50 HIV-TB+ patients. Disseminated TB was present in eight of 13 HIV+TB+ patients and four of five HIV-TB+ patients with PR. In 28 HIV+TB+ patients starting HAART, PR was significantly associated with commencing HAART within 6 weeks of starting antituberculosis treatment (p = 0.03) and was more common in those with disseminated TB (p = 0.09). No association was found between development of PR and baseline CD4 count or CD4 response to HAART. CONCLUSIONS: PR is common in HIV infected and uninfected individuals with TB. Early introduction of HAART and the presence of disseminated TB appear to be important in co-infected patients.