Chest
Volume 134, Issue 3, September 2008, Pages 589-594
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Original Research
Infection
Unexpected Pulmonary Involvement in Extrapulmonary Tuberculosis Patients

https://doi.org/10.1378/chest.08-0319Get rights and content

Background

This study aimed to assess the utility of sputum examinations and chest radiographs (CXRs) in patients with extrapulmonary tuberculosis (XPTB) to detect pulmonary involvement of tuberculosis (TB).

Methods

We studied 72 XPTB patients who were managed through the TB Program, King County, WA, from January 2003 through November 2004.

Results

The two most common sites of XPTB were the lymph nodes (36 [50%]) and pleura (12 [17%]). Thirty-five of 72 XPTB patients (49%) had abnormal CXR findings. Sputum was not obtained from 15 patients despite sputum induction. Of the 57 patients from whom sputum was collected, 30 (53%) had abnormal CXR findings, 5 (9%) had sputum smears that were positive for acid-fast bacilli, and 12 (21%) had sputum cultures that were positive for Mycobacterium tuberculosis. Weight loss was significantly associated with positive sputum culture findings in a multivariate analysis (odds ratio, 4.3; 95% confidence interval, 1.01 to 18.72; p = 0.049). There was no significant difference in the occurrence of positive sputum culture results between patients with abnormal CXR findings and those with normal CXR findings (7 of 30 patients [23%] vs 5 of 27 patients [19%], respectively; p = 0.656). Of 24 HIV-negative XPTB patients with normal CXR findings, 2 patients (8%) had positive sputum culture findings.

Conclusions

CXR results did not reliably differentiate XPTB patients with and without positive sputum culture findings. Some XPTB patients had positive sputum culture results despite normal CXR findings and negative HIV status. Weight loss in XPTB patients was associated with positive sputum culture results. Sputum examinations in XPTB patients, regardless of the CXR results, may identify potentially infectious cases of TB.

Section snippets

Patient Selection and Data Collection

Patients with XPTB who were seen at the TB Control Program, Public Health–Seattle & King County, WA, between January 2003 and November 2004 were retrospectively reviewed. The initial evaluations included the following: (1) symptom review; (2) physical examination; (3) CXRs; (4) HIV counseling and testing, if these had not been obtained within 6 month prior to TB diagnosis; and (5) obtaining of sputum samples for performing AFB smears and cultures. From the patients with normal CXR findings, one

Demographic Data

During a 23-month period, 74 XPTB patients were seen by the TB Control Program, Public Health, Seattle & King County. Of those patients, 2 children were < 9 years of age, resulting in 72 eligible patients in the cohort. Patient characteristics are described in Table 1. The majority of patients was foreign born (59 patients; 82%), mostly Asian (32 patients; 44%). HIV serology results were available for 57 patients (79%); 5 of 57 patients (9%) were HIV positive. The most common XPTB site was the

Discussion

This study described the CXR findings of 72 XPTB patients and sputum examinations of 57 XPTB patients. The main objective was to assess the value of CXRs and sputum examinations for the identification of XPTB patients with pulmonary involvement, especially those with unrecognized disease, who could be potentially infectious. A few other analyses of the study were performed (1) to find predictors of culture-positive sputum among XPTB cases11, 12, 13, 14, 15 and (2) to examine whether collecting

Acknowledgment

The authors thank John Jereb, MD (Centers for Disease Control and Prevention, Atlanta, GA) for providing critical feedback on the manuscript.

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    The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

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