The diagnosis of smear-negative pulmonary tuberculosis: the practice of sputum smear examination in Malawi.

SETTING: Forty hospitals in Malawi (3 central, 22 district and 15 mission) performing smear microscopy and registering tuberculosis patients. OBJECTIVE: To determine, in patients aged 15 years or above, 1) the proportion with smear-negative pulmonary tuberculosis (PTB) who had sputum smears examined, 2) the number of sputum smears examined per patient, and 3) the proportion of patients registered with smear-positive and smear-negative PTB. DESIGN: Data collection during three 6-month periods, from January 1997 to June 1998, using tuberculosis registers, laboratory sputum registers and quarterly reports. RESULTS: Of 6301 smear-negative PTB patients, 84% had sputum smears examined, the rate increasing from 76% in January-June 1997, to 85% in July-December 1997, to 89% in January-June 1998. Of patients who submitted sputum (where the number of smears was recorded), 99% had two or more smears examined and 93% had three smears examined. In district and mission hospitals performance improved over time, while in central hospitals results were more variable. During the same 18-month period 21 422 patients aged 15 years or more were registered with PTB: 59% with smear-positive PTB and 41% with smear-negative PTB; this pattern was similar in each 6-month period. CONCLUSION: The study suggests that it is reasonable to aim for a target of 90% or more of smear-negative PTB patients having sputum smears examined.     

High early death rate in tuberculosis patients in Malawi.

SETTING: Thirty-eight district and mission hospitals in Malawi. OBJECTIVES: In patients registered with all types of tuberculosis (TB) in 1997 to determine 1) treatment outcomes, and 2) when in the course of anti-tuberculosis treatment TB deaths occurred. DESIGN: A retrospective study using information from TB registers, health centre registers, TB treatment cards and TB ward admission books. RESULTS: A total of 16,004 patients were registered with all types of TB, 6471 with smear-positive pulmonary tuberculosis (PTB), 5305 with smear-negative PTB and 4228 with extra-pulmonary tuberculosis (EPTB). Of patients with all types of TB, 3720 (23%) died: death rates were 22% in smear-positive PTB, 26% in smear-negative PTB and 22% in EPTB. Month of death was known in 3371 patients (91% of those who died) and day of death in 3326 patients (89% of those who died). In patients who died, 19% of deaths occurred by day 7 and 41% by the end of the first month of treatment. A higher proportion of early deaths occurred in patients with smear-negative PTB and EPTB and in relation to increasing age. CONCLUSIONS: There was a high overall death rate in TB patients registered in 1997, with 40% of deaths occurring in the first month of treatment. Strategies to combat this problem are needed.     

How can detection of infectious tuberculosis be improved? Experience in the Somali region of Ethiopia.

In early 1999, 48% of pulmonary tuberculosis (PTB) cases detected in the Somali region of Ethiopia were smear-positive. Actions at the laboratory level and peer-review of smear-negative PTB diagnoses were proposed. Clinicians knew, but did not adhere to, the algorithm recommended by the National Tuberculosis Programme for these diagnoses, partly due to the costs involved to patients. Challenging clinicians, in a non-threatening way, to become more clinically rigorous proved successful, and the proportion of smear-positive PTB increased to 65%. Operational research is needed to assess the feasibility of these widely-recommended smear-negative PTB diagnosis guidelines.     

Evaluation of a unified treatment regimen for all new cases of tuberculosis using guardian-based supervision.

SETTING: Ntcheu District, Malawi, using an oral antituberculosis treatment regimen. OBJECTIVE: To determine whether directly observed treatment (DOT) during the initial phase of treatment supervised either in hospital, at health centres or by guardians in the community, was associated with 1) satisfactory 2-month and 8-month treatment outcomes, and 2) with a reduction of in-patient hospital-bed days. DESIGN: Prospective data collection of all tuberculosis (TB) patients registered between 1 April 1996 and 30 June 1997, with 2-month and 8-month treatment outcomes, sputum smear conversion in smear-positive pulmonary TB patients (PTB) and in-patient hospital-bed days. RESULTS: Among the 600 new patients, 302 had smear-positive PTB, 150 smear-negative PTB and 148 extrapulmonary TB (EPTB). Eight-month treatment completion was 65% for smear-positive PTB patients, which was significantly higher than in patients with smear-negative PTB (45%) and EPTB (54%), due mainly to high 8-month mortality rates. The site of the intensive phase was determined in 596 patients: 178 (30%) received DOT from guardians, 115 (19%) from a health centre and 303 (51%) in hospital. At 2 months, mortality rates were significantly higher in hospitalised patients. Two-month treatment outcomes (including sputum smear conversion rates in smear-positive PTB patients) were similar between patients receiving DOT at health centres or from guardians. Decentralised DOT resulted in a 25% reduction in hospital-bed days in patients alive at 2 months compared with that predicted using the old regimens. CONCLUSION: Decentralising DOT to health centres and to guardians during the intensive phase is associated with satisfactory treatment outcomes.     

Clinical diagnosis of smear-negative pulmonary tuberculosis: an audit of diagnostic practice in hospitals in Malawi.

SETTING: Thirty-seven hospitals in Malawi. OBJECTIVE: To audit the hospital practice of clinically diagnosing adults with smear-negative pulmonary tuberculosis (PTB). DESIGN: A cross-sectional survey of adults aged 15 years or above who were registered and receiving inpatient treatment for smear-negative PTB. An assessment of each patient was carried out to determine 1) the number of recommended diagnostic guidelines (cough >3 weeks, no response to antibiotics, negative sputum smears and a chest radiograph compatible with PTB) used by hospital staff in making the diagnosis of PTB, and 2) whether the clinical diagnosis of smear-negative PTB was correct according to criteria set by the study. RESULTS: There were 259 patients, 127 men and 132 women, with a mean age of 37 years; 93% had a cough >3 weeks, 95% had received one or more courses of antibiotics, 92% had submitted sputum samples for smear examination and 97% had chest radiographs performed. In 148 (57%) patients, all four diagnostic guidelines were used, and in 238 (92%) patients three or more were used. The diagnosis of smear-negative PTB was considered correct by study criteria in 203 (78%) patients. In the remainder, 22 (8%) were considered to have extrapulmonary TB and 34 (14%) another diagnosis. CONCLUSION: Hospital practices in the diagnosis of smear-negative PTB are reasonable, although there is room for improvement with in-service training and regular audits of practice.     

HIV and tuberculosis coinfection in the southern region of Ethiopia: a prospective epidemiological study

HIV has played a key role in TB, modifying its incidence and clinical presentation. This study describes the prevalence of HIV among TB patients attending health facilities in the southern region of Ethiopia. The HIV prevalence was 18% for female and 21% for male TB patients. 15% and 30%, respectively, of the rural and urban patients with TB were HIV positive (p<0.05). 19% (51/261) smear-positive PTB, 26% (36/137) smear-negative PTB and 11% (10/94) of the extrapulmonary TB patients were HIV positive. The proportion of patients with extra-PTB varied from 11% to 38% across the centres and was highest in the zones with the lowest HIV prevalence. In the light of limited diagnostic facilities, clinicians often make a clinical diagnosis of TB without laboratory confirmation. The increase in the number of TB cases could be due to HIV. However, the number of health facilities offering TB treatment in the area also increased (from 53 to 236) during the same period and the increase in TB is likely to be the result of a combination of factors, including improved detection and HIV. It is important to consider this multi-factorial phenomenon when interpreting the increase of TB in a geographical area.     

全国初治涂阴肺结核病例登记现状分析

目的分析全国各省初治涂阴肺结核病例登记现状,为评价初治涂阴肺结核病例诊断质量提供依据。方法根据2004—2005年全国结核病防治规划报表中初治涂阴和初治涂阳肺结核病例登记资料,分析各省2年初治涂阴肺结核病例登记率变化和增长幅度;统计各省及不同地区初治涂阴与初治涂阳肺结核病例登记率;对各省初治涂阴与初治涂阳肺结核病例登记率进行直线回归分析。结果2005年全国登记初治涂阴肺结核病例316 405例,登记率为24.27/10万,各省登记率在6.01/10万72.17/10万;2005年登记初治涂阴病例数比2004年增加了19.9%,其中2个省登记数呈负增长,其余各省登记数增长了0.5%62.3%;2005年全国初治涂阳病例登记率是涂阴病例登记率的1.5倍,其中23个省初治涂阳病例登记率高于涂阴病例登记率,8个省相反;初治涂阴病例占初治涂阳病人登记率的比例,京津沪地区为149.28%,非项目地区为83.6%,项目地区为50.3%;对涂阳和涂阴病例登记率进行直线回归分析,回归方程y=22.342+0.563 6x。结论对初治涂阴肺结核患者实行免费政策后,全国涂阴肺结核病例登记率提高。但各省初治涂阴病例登记率和增长幅度以及涂阴病例登记率与涂阳病例登记率的比例悬殊。由于涂阴病例诊断困难,对于涂阴病例登记率高或增长幅度大的地区,特别在DOTS执行时间短和人力资源有限的地区,应对涂阴病例诊断质量予以进一步检查和评价。     

武汉市青山区2005-2012年肺结核控制情况分析

目的 了解武汉市青山区2005-2012年结核病控制工作情况,为全区2011-2015年结核病防治规划的实施提供依据。 方法 统计分析武汉市青山区8年的结核病资料、手工季度和年度报表及《中国结核病控制信息系统》数据资料,率的比较采用χ²检验。 结果 2005-2012年青山区登记活动性肺结核患者2848例,其中男2100例,女748例。男性活动性肺结核、新涂阳肺结核、复治涂阳肺结核和涂阴肺结核患者分别为女性患者的2.8倍（2100/748）、3.3倍（949/289）、5.3倍（159/30）和2.3倍（992/429）。初治涂阳和复治涂阳患者均以65～岁组老人为主,共计263例和52例,初治涂阳前三位从高到低依次为65～岁（263例）、45～岁（239例）、55～岁（159例）;而涂阴则由高到低前三位依次为25～岁（268例）、15～岁（259例）、35～岁（242例）;活动性肺结核职业分布上,离退休人员最多（711例),工人和家政家务及待业人员居第二位(647例)和第三位(489例)。年平均登记率分别为：活动性肺结核78.6/10万,初治涂阳34.2/10万,复治涂阳5.2/10万,涂阴39.2/10万;962例涂阳患者治愈,2008年及以后治愈率达90%及以上。因症就诊患者1073例,结核病防治机构因症就诊的活动性肺结核和涂阳肺结核患者由2005年的41.0%(133/324)和52.6%(70/133）下降到2012年的11.9%（40/336）和47.5%（19/40）;非结核病专科医院查出1477例活动性肺结核和722例涂阳肺结核患者。 结论 武汉市青山区登记活动性肺结核患者男性多于女性,老年离退休患者居多,肺结核患者登记率不高,结核病防治机构因症就诊率下降。     

Health-seeking behaviour of new smear-positive TB patients under a DOTS programme in Tamil Nadu, India, 2003.

BACKGROUND: Although case detection is above 70% in Tamil Nadu after DOTS implementation, an assessment of the timeliness of patient diagnosis and treatment is still needed. OBJECTIVE: To study the health-seeking behaviour of new smear-positive pulmonary tuberculosis (PTB) patients treated at government facilities. METHODS: New smear-positive patients diagnosed and treated between January and March 2003 in government facilities of randomly selected blocks in Tamil Nadu were interviewed using a semi-structured interview schedule. RESULTS: Of 601 patients interviewed, 65% contacted a provider within 28 days. The first contact was governmental for 47% and non-governmental for 53%. Median total, patient and provider delays were respectively 62, 28 and 28 days; provider delay was 9 days with government and 50 with private provider. In multivariate analysis, patient delay was significantly associated with smoking (P < 0.001) and mode of travel (P < 0.01), and provider delay with first consultation with a private provider (P < 0.001) and distance > 5 km from the health facility (P < 0.01). Twenty-five per cent of patients took more than two actions before diagnosis. CONCLUSION: Community awareness of TB needs to be increased. Greater private sector involvement in the Revised National Tuberculosis Control Programme is essential to reduce provider delay. Referral and sputum transportation to the diagnostic facility should be given priority.     

Patient and health care system delays in the diagnosis and treatment of tuberculosis.

SETTING: All culture-positive tuberculosis patients without previous treatment for tuberculosis (n = 184), New York City, April 1994. OBJECTIVE: To examine factors associated with delays in presenting to a health care provider (patient delay) and in starting antituberculosis treatment (health care system delay). DESIGN: Retrospective medical record review and patient interviews. RESULTS: Median total delay was 57 days (range 4-764), 35 for acid-fast bacilli smear-positive patients and 79 for smear-negative patients (P < 0.001). Median patient delay was 25 (range 0-731). Median health care system delay was 15 days, 6 for smear-positive patients and 31 for smear-negative patients (P < 0.001). In logistic regression, age 55-64 years (adjusted odds ratio [OR(adj)] 10.6, 95% confidence interval [CI] 1.3-86.9), and primary language other than English (OR(adj) 2.5, 95%CI 1.0-5.8), were associated with longer patient delays. Homelessness (OR(adj) 7.1, 95%CI 1.05-33.5), not having a chest radiograph at the first medical visit (OR(adj) 2.4, 95%CI 1.0-5.4), negative smear (OR(adj) 10.2, 95%CI 4.4-23.3) and absence of cough (OR(adj) 2.9, 95%CI 1.2-6.8) were associated with longer health care system delays. CONCLUSION: To reduce delays, patients should be educated to seek care more quickly, and should be provided with culturally appropriate health care and language services. Physicians should maintain a high index of suspicion for tuberculosis and perform appropriate diagnostic tests.     

Relationship between estimated pretest probability and accuracy of automated Mycobacterium tuberculosis assay in smear-negative pulmonary tuberculosis

BACKGROUND: The AMPLICOR assay (Roche; Branchburg, NJ), a rapid direct amplification test for Mycobacterium tuberculosis, has only been licensed for use in smear-positive respiratory specimens. However, many patients with pulmonary tuberculosis (PTB) have smear-negative disease. The clinical utility of this test in patients with smear-negative PTB is unknown. OBJECTIVE: To evaluate the effect of pretest probability of PTB estimated by chest physicians on the accuracy of the AMPLICOR assay in patients with smear-negative PTB. Design and methods: A prospective study of consecutive patients suspected of having smear-negative PTB. Two chest physicians estimated the pretest probability of active disease (high, intermediate, and low categories). Respiratory specimens were examined with radiometric broth medium cultures and with the AMPLICOR assay for M tuberculosis. The decision on a final diagnosis of PTB was blinded to the AMPLICOR results. RESULTS: Active PTB was diagnosed in 25 of 441 patients (5.7%). The AMPLICOR assay had an overall sensitivity of 44% and a specificity of 99%. Results of the assay were negative in seven patients with culture-negative PTB. The proportions of patients in the high, intermediate, and low pretest groups were 4.5%, 19.7%, and 75.7%, respectively. The incidence of PTB for each group was 95%, 3.4%, and 0.9%, respectively. The sensitivities of the AMPLICOR assay in the three groups of patients were 47%, 33%, and 33%, respectively, while the specificities were 100%, 98%, and 99%, respectively. CONCLUSIONS: In patients suspected of having smear-negative PTB, the following conclusions were drawn: (1) the incidence of active PTB was low; (2) pretest estimates accurately discriminated between patients with high and low risk of PTB; (3) the risk of PTB was overestimated in the intermediate group; and (4) the utility of the AMPLICOR assay in the intermediate-risk group may be limited by the overestimation of disease prevalence and low test sensitivity. Further studies are needed on the role of the AMPLICOR assay in better selected patients with an intermediate risk of having smear-negative PTB.     

Risk factors for delay in the diagnosis and treatment of tuberculosis at a referral hospital in Rwanda.

SETTING: Kigali University Hospital, the main referral centre for TB in Rwanda. OBJECTIVE: To evaluate delays in the diagnosis and treatment of tuberculosis (TB) and associated risk factors. DESIGN: Prospective data collection of patients treated for pulmonary TB (PTB) or extra-pulmonary TB (EPTB) between June and September 2006. RESULTS: Of 104 patients with a mean age of 35 years (range 17-84) recruited into the study, 62% were HIV-positive. EPTB was diagnosed in 60 cases. The median total, health care and patient delays were respectively 57, 28 and 25 days. The health system delay before referral was significantly longer than the delay at our institution (18 vs. 6 days, P<0.0001). Risk factors for a longer health system delay at our institution were smear-negative PTB or EPTB (OR 5.12) and a trial of antibiotics (OR 2.96). The latter was also found to significantly prolong total delay (OR 2.85), as did rural residence (OR 4.86). No significant association was found between patient delay and age, sex, profession or health insurance status. CONCLUSION: Smear-negative PTB and EPTB were associated with longer health system delays. A trial of antibiotics significantly increased the health system delay. Its use, recommended by the World Health Organization in case of smear-negative TB and EPTB in developing countries, needs validation at the tertiary health care level.     

Use of the amplified mycobacterium tuberculosis direct test in a public health laboratory: test performance and impact on clinical care

BACKGROUND: The Amplified Mycobacterium tuberculosis Direct Test (MTD; Gen-Probe; San Diego, CA) is a nucleic-acid amplification test for rapid pulmonary tuberculosis (PTB) diagnosis. In a routine public health setting, test accuracy and impact on clinical decisions are unknown. METHODS: Retrospectively, we evaluated MTD accuracy and impact on clinical decisions in a public health setting. To estimate MTD accuracy, mycobacterial culture was used as the "gold standard." To evaluate MTD impact on clinical decisions, concordance of clinician presumptive diagnosis (at time of MTD and smear availability) and definitive diagnosis, and duration of nonindicated tuberculosis therapy were determined for smear-positive PTB suspects in a period of MTD availability (MTD group) and a prior period of MTD nonavailability (non-MTD group). RESULTS: A total of 1,151 respiratory specimens from 638 PTB suspects were analyzed. MTD sensitivity, specificity, positive predictive value, and negative predictive value were 91.7%, 98.7%, 96.7%, and 96.5% overall, respectively; and 98.7%, 97.8%, 98.7%, and 97.8% for smear-positive patients; and 62.2%, 98.9%, 85.2%, and 96.1% for smear-negative patients. In the MTD group, concordance between definitive and clinician presumptive diagnoses was 78% (95% confidence interval [CI], 64 to 88%), similar to that for the non-MTD group (79%; 95% CI, 68.4 to 89.6%). However, concordance between definitive diagnosis and the MTD test was 98% (95% CI, 94.1 to 100%). Median duration of nonindicated tuberculosis treatment was 6 days for the MTD group vs 31 days for the non-MTD group (p = 0.002). CONCLUSION: In this public health setting, MTD was accurate and rapidly detected more than half of the smear-negative PTB cases. For smear-positive PTB suspects, MTD had excellent concordance with definitive diagnosis, but clinicians often inappropriately initiated TB therapy despite a negative MTD result.     

Care seeking behaviour and diagnostic processes in patients with smear-positive pulmonary tuberculosis in Malawi.

SETTING: Government hospitals in five districts in Malawi. OBJECTIVE: To determine care seeking behaviour and diagnostic processes in patients newly diagnosed with smear-positive pulmonary tuberculosis (PTB). DESIGN: Structured questionnaires completed by interview between January to September 1998. RESULTS: During the study period 1,518 patients were registered with PTB, of whom 1,099 (72%) were interviewed. The median delay between onset of cough and diagnosis was 8 weeks. There was a variable pattern of care seeking behaviour, with 70% of patients initially visiting a place of orthodox medical care and 30% visiting traditional healers, grocery shops, etc. Of these, 867 (79%) patients had one or more subsequent contacts for help, with these visits targeted more to orthodox medical care. At all stages, antibiotics resulted in symptomatic improvement in up to 40% of cases. There was a median time of 7 weeks between cough and first submission of sputum specimens. Almost all patients received sputum smear results after a median length of 4 days; 474 (43%) of patients were only aware of their diagnosis at the time of receiving smear results, this observation being significantly associated with lack of schooling and not knowing another person with TB. CONCLUSION: More needs to be done to educate communities and non-orthodox care providers about the diagnosis and treatment of TB.     

Childhood tuberculosis in Malawi: nationwide case-finding and treatment outcomes.

SETTING: All 43 non-private hospitals (three central, 22 [corrected] district and 18 [corrected] mission) in Malawi that register and treat adult and paediatric TB cases. OBJECTIVE: To assess the rate, pattern and treatment outcome of childhood TB case notifications in Malawi in 1998. DESIGN: Retrospective data collection using TB registers, treatment cards and information from health centre registers. Information was collected on number of cases, types of TB and treatment outcomes using standardised definitions. RESULTS: There were 22,982 cases of TB registered in Malawi in 1998, of whom 2,739 (11.9%) were children. Children accounted for 1.3% of all case notifications with smear-positive pulmonary TB (PTB), 21.3% with smear-negative PTB and 15.9% with extra-pulmonary TB (EPTB). Estimated rates of TB in children were 78/ 100,000 in those aged less than one year, 83/100,000 in those aged 1-4 years and 33/100,000 in those aged 5-14 years. A significantly higher proportion of TB cases was diagnosed in central hospitals. Only 45% of children completed treatment. There were high rates of death (17%), default (13%) and unknown treatment outcomes (21%). Treatment outcomes were worse in younger children and in children with smear-negative PTB. Treatment completion was best (76%) and death rates lowest (11%) for the 127 children with smear-positive PTB. CONCLUSION: Childhood TB is common in Malawi and treatment outcomes are poor. Research should be directed towards improved diagnosis and follow-up of children with TB, and the National TB Programme should support appropriate management of childhood contacts of smear positive PTB cases.     

Are community surveys to detect tuberculosis in high prevalence areas useful? Results of a comparative study from Tiruvallur District, South India.

BACKGROUND: In Tiruvallur District, South India, tuberculosis cases are detected at health facilities (HF) as part of a DOTS programme, and by screening adults through community survey (CS) as part of ongoing epidemiological research. OBJECTIVE: To compare socio-demographic, clinical and bacteriological characteristics and treatment outcomes of all patients detected at HF with those of all patients detected by CS during a 12-month period. RESULTS: Of 32,663 adults surveyed, 100 had smear-positive and 116 had smear-negative tuberculosis; of 65 smear-positive patients who began treatment, 44 were cured. Compared to HF patients, CS patients were significantly more likely to be older (AOR = 1.9), male (AOR = 2.7), non-literate (AOR = 1.7), and living in poor quality housing (AOR = 2.0), and were less likely to have cough >3 weeks (AOR = 3.4) or smear-positive tuberculosis (AOR = 4.2). Of 61 new smear-positive CS patients, 40 reported chest symptoms; of these, 32 (80%) had already consulted a health-care provider, but remained undiagnosed. CONCLUSIONS: The community survey was of little value in tuberculosis case detection even in this high-prevalence setting. Patients identified by the survey were less symptomatic and less infectious, and less than half were cured. Diagnostic services should be made more accessible to the elderly, the non-literate and men.     

山东省4地市城区登记肺结核患者诊断状况的调查分析

目的 了解山东省城区登记的结核病人就诊情况和确诊情况，为提高城区的结核病服务质量提出建议。方法 对山东省泰山区等4个地级市的城区结防机构登记的246例肺结核病人进行问卷调查。 结果 病人自发病至初次就诊平均间隔12 d，病人延误的主要原因是对病情不在乎；67.5%的病人存在确诊延误，不同婚姻状况和选择不同首诊机构的患者，确诊延误的差异具有统计学意义。 结论 需要开展群众性健康教育，提高结核病知晓率，使病人出现结核病疑似症状后及时就诊；应鼓励结核可疑者在发病后首选结防机构、区级以上综合医疗机构或专科医院就诊。     

Patient and health system delays in the diagnosis of tuberculosis in Southern Thailand after health care reform.

SETTING: Seven public hospitals in a southern province of Thailand. OBJECTIVES: To measure delays in tuberculosis (TB) diagnosis and to examine the factors associated with these delays, with special focus on the effect of drug store utilisation and health insurance coverage on patient delay. DESIGN: A total of 202 newly diagnosed smear-positive and smear-negative pulmonary TB patients were interviewed using a structured questionnaire. RESULTS: The median patient, health system and total delay were 4.4, 2.8 and 9.4 weeks, respectively. Risk factors for patient delay were age 31-60 years, having mild illness, previous similar symptoms and first presenting to non-qualified providers. Health insurance was not associated with a shorter patient delay. Health system delay was significant longer for patients with health insurance and first presenting to low-level public health facility (i.e., community hospital, health centre, primary care unit or private clinic/hospital). CONCLUSIONS: The public should be informed how to recognise TB symptoms to shorten patient delay. The Thai National Tuberculosis Control Programme needs to supervise the private health sector, including drug stores, for better TB control. Drug store personnel need to be trained to recognise and refer TB suspects. The capacity of low-level public health facilities and private doctors in TB diagnosis needs improvement. A proper referral system should be developed.     

Useful clues to the presence of smear-negative pulmonary tuberculosis in a West African city.

OBJECTIVE: Tuberculosis suspects with negative sputum smears for acid-fast bacilli (AFB) may have either pulmonary tuberculosis (PTB) or some other pulmonary disease (non-PTB). The aim of this study was to improve the differentiation between PTB and non-PTB. DESIGN: We enrolled 396 tuberculosis suspects 15 years of age or older who had cough of 21 days or longer and three negative AFB smears. Non-PTB was diagnosed by clinical and radiographic responses to amoxicillin; smear-negative PTB was diagnosed by positive culture for Mycobacterium tuberculosis or response to antituberculosis chemotherapy. RESULTS: Multivariate analysis, without X-ray variables, of 79 patients with a final diagnosis of non-PTB and 110 patients with smear-negative PTB indicated that age less than 37 years, family contact with TB, never having been married, loss of weight, lack of expectoration, human immunodeficiency virus (HIV) seropositivity, and tuberculin reactivity were significantly associated with PTB. When the initial X-ray findings were included, age younger than 37 years, lack of expectoration, HIV seropositivity, and tuberculin reactivity remained in the model, and cavitation and patchy densities were significantly associated. CONCLUSION: The response to 10 days of amoxicillin and certain demographic, clinical and radiographic characteristics are useful in separating non-PTB from PTB in tuberculosis suspects with negative AFB smears.