Risk factors for extra-pulmonary tuberculosis compared to pulmonary tuberculosis.

BACKGROUND: Tuberculosis (TB) continues to be a major global health problem. Extra-pulmonary TB (EPTB) manifests with protean symptoms, and establishing a diagnosis is more difficult than pulmonary TB (PTB). SETTING: A university-affiliated hospital in southern Taiwan. OBJECTIVE: To analyse the risk factors for EPTB compared with PTB. DESIGN: This retrospective study compared patients with EPTB and PTB in southern Taiwan by analysing their demographic data and clinical underlying diseases. Risk factors for EPTB were further analysed. RESULTS: A total of 766 TB patients were enrolled in this study, with 102 (13.3%) EPTB and 664 (86.7%) PTB cases. Of the 766 patients, 3% of PTB patients had EPTB, while 19.6% of EPTB patients also had PTB. The most frequently involved EPTB site was the bone and joints (24.5%). The incidence of EPTB vs. PTB decreased significantly for each decade increase in patient age. Multivariate logistic regression analysis showed that being female, not being diabetic, having end-stage renal disease and not smoking were independent risk factors for EPTB. CONCLUSION: This study defines the risk factors for EPTB compared with PTB. Awareness of these factors is essential for physicians to have a high index of suspicion for accurate and timely diagnosis.

High prevalence of latent tuberculosis infection in patients in end-stage renal disease on hemodialysis: Comparison of QuantiFERON-TB GOLD, ELISPOT, and tuberculin skin test.

BACKGROUND: Individuals with end-stage renal disease (ESRD) are 10- to 25-fold more likely than immunocompetent people to develop active tuberculosis (TB) and are candidates for being treated for latent TB infection (LTBI). However, diagnosis using the tuberculin skin test (TST) is doubly difficult due to cutaneous anergy and cross-reactions with Bacille-Calmette-Guérin (BCG) vaccination. MATERIALS AND METHODS: This was a prospective, doublematched, cohort study in which 32 ESRD patients and 32 age-matched, healthy controls were enrolled. The TST and two new interferon-gamma blood tests, QuantiFERON-TB Gold (QFT-G) and T-SPOT.TB (ELISPOT), were performed. The subjects were followed up 2 years for active TB disease. ELISPOT was done in ESRD patients only. RESULTS: Compared to the healthy controls, a high prevalence of LTBI was found in the ESRD patients by TST (62.5%, 95% confidence interval [CI] 43.7-78.9), QFT-G (40.0%, 95% CI 22.7-59.4), and ELISPOT (46.9%, 95% CI 29.1-65.3). Agreement was moderate (kappa [kappa] = 0.53) for QFT-G and ELISPOT but only slight between TST and QFT-G (kappa = 0.25) and fair between TST and ELISPOT (kappa = 0.32). ESRD (p = 0.03) and diabetes mellitus (p = 0.04) were significant risk factors for QFT-G positivity on the multivariable analysis. The overall rate of active TB was 1.66 cases per 100 person-years (pys), with the rate higher in patients with ESRD (3.53 per 100 pys) and those with positive (3.40 per 100 pys) and indeterminate QFT results (30.16 per 100 pys), although the difference was not statistically significant. Sensitivity, specificity, and positive and negative predictive values of QFT-G for active TB was 100%, 62.1%, 8.3% and 100%. CONCLUSION: This pilot study is the first to compare QFT-G, ELISPOT, and TST in ESRD patients on hemodialysis and demonstrates a high prevalence of LTBI in this population. In our study, the QFT-G was the more accurate method for identifying those truly infected with Mycobacterium tuberculosis, even in BCG-vaccinated individuals.

Fever of unknown origin in Taiwan.

BACKGROUND: Fever of unknown origin (FUO) is a challenging problem worldwide. There was no prospective study of FUO in the past two decades in Taiwan. A prospective study was conducted. MATERIALS AND METHODS: The prospective study was undertaken from March 2001 to May 2002. All patients fulfilling the modified criteria for FUO, either admitted, referred or consulted in a medical center in southern Taiwan, were enrolled for analysis. RESULTS: A total of 94 cases met the criteria of FUO. The final diagnoses of FUO consisted of 54 infectious diseases (57.4%), 8 hematologic/neoplastic (8.5%), 7 noninfectious inflammatory (7.4%), 8 miscellaneous (8.5%) and 17 undiagnosed (18.1%) cases. The single most common cause of FUO was tuberculosis. Some infectious diseases, such as rickettsiosis and melioidosis, were rarely reported in western countries. Three patients with hemophagocytotic syndrome without ascertainable etiologies were present with FUO in this study. Between the patients with and those without a final diagnosis, the short-term survival (3 months) was compared by the Kaplan-Meier analysis, which revealed no difference. CONCLUSIONS: Mycobacteriosis is still the leading cause of FUO in Taiwan and it is important to identify this treatable disease from all causes of FUO. This study has showed geographical variation among the studies of FUO.

Residential water supply as a likely cause of community-acquired Legionnaires' disease in an immunocompromised host.

A 69-year-old man with Sweet's syndrome and myelodysplastic syndrome presented with pneumonia and respiratory distress. He had been taking corticosteroids and methotrexate. The diagnosis of Legionnaires' disease was established by the isolation of Legionella pneumophila serogroup 6 from sputum and a fourfold seroconversion of Legionella antibodies to 1:512. Legionella pneumophila serogroup 6 was isolated from faucets in two homes owned by the patient. Strains of Legionella pneumophila serogroup 6 isolated from the patient's sputum and from one home were demonstrated to be genetically identical by pulsed-field gel electrophoresis but different from strains found in the other home and in a hospital outpatient clinic that he visited. This case illustrates an emerging public health issue concerning acquisition of community-acquired Legionnaires' disease from the homes of immunocompromised hosts. This is the first such case reported in Asia.