Alonso Soto

Performance of an algorithm based on WHO recommendations for the diagnosis of smear‐negative pulmonary tuberculosis in patients without HIV infection

Objective  To evaluate the performance of an algorithm based on WHO recommendations for diagnosis of smear‐negative pulmonary tuberculosis in HIV‐negative patients.

Validation of a clinical-radiographic score to assess the probability of pulmonary tuberculosis in suspect patients with negative sputum smears.

Background Clinical suspects of pulmonary tuberculosis in which the sputum smears are negative for acid fast bacilli represent a diagnostic challenge in resource constrained settings. Our objective was to validate an existing clinical-radiographic score that assessed the probability of smear-negative pulmonary tuberculosis (SNPT) in high incidence settings in Peru. Methodology/Principal Findings We included in two referral hospitals in Lima patients with clinical suspicion of pulmonary tuberculosis and two or more negative sputum smears. Using a published but not externally validated score, patients were classified as having low, intermediate or high probability of pulmonary tuberculosis. The reference standard for the diagnosis of tuberculosis was a positive sputum culture in at least one of 2 liquid (MGIT or Middlebrook 7H9) and 1 solid (Ogawa) media. Prevalence of tuberculosis was calculated in each of the three probability groups. 684 patients were included. 184 (27.8%) had a diagnosis of pulmonary tuberculosis. The score did not perform well in patients with a previous history of pulmonary tuberculosis. In patients without, the prevalence of tuberculosis was 5.1%, 31.7% and 72% in the low, intermediate and high probability group respectively. The area under de ROC curve was 0.76 (95% CI 0.72–0.80) and scores ≥6 had a positive LR of 10.9. Conclusions/Significance In smear negative suspects without previous history of tuberculosis, the clinical-radiographic score can be used as a tool to assess the probability of pulmonary tuberculosis and to guide the decision to initiate or defer treatment or to requesting additional tests.

Evaluation of Clinical Prediction Rules for Respiratory Isolation of Inpatients with Suspected Pulmonary Tuberculosis

BACKGROUND In the framework of hospital infection control, various clinical prediction rules (CPRs) for respiratory isolation of patients with suspected pulmonary tuberculosis (PTB) have been developed. Our aim was to evaluate their performance in an emergency department setting with a high prevalence of PTB. METHODS We searched the MEDLINE and OVID databases to identify CPRs to predict PTB. We used a previously collected database containing clinical, radiographical, and microbiological information on patients attending an emergency department with respiratory complaints, and we applied each CPR to every patient and compared the result with culture for Mycobacterium tuberculosis as the reference standard. We also simulated the proportion of isolated suspects and missed cases for PTB prevalences of 5% and 30%. RESULTS We withheld 13 CPRs for evaluation. We had complete data on 345 patients. Most CPRs achieved a high sensitivity but very low specificity and very low positive predictive value. Mylottes score, which includes results of sputum smear as a predictive finding, was the best-performing CPR. It attained a sensitivity of 88.9% and a specificity of 63.9%. However, at a 30% PTB prevalence, 498 of 1000 individuals with suspected PTB would have to be isolated; 267 of these cases would be true PTB cases, and 33 cases would be missed. Two consecutive sputum smears had a sensitivity of 75.6% and a specificity of 99.7%. CONCLUSIONS In a setting with a high prevalence of PTB, only 1 of the 13 assessed CPRs demonstrated high sensitivity combined with satisfactory specificity. Our results highlight the need for local validation of CPRs before their application.

Algorithm for the diagnosis of smear-negative pulmonary tuberculosis in high-incidence resource-constrained settings

Diagnosis of smear‐negative pulmonary tuberculosis (SNPT) remains a challenge, particularly in resource‐constrained settings. We evaluated a diagnostic algorithm that combines affordable laboratory tools and a clinical prediction rule (CPR).

Recursos Humanos en Salud

El mundo enfrenta una crisis de recursos humanos en salud, la cual afecta particularmente a paises en vias de desarrollo. De acuerdo al Informe sobre la salud en el mundo del 2006 (1), existe un grupo de 57 paises, la mayoria de ellos africanos, con deficiencias criticas en la cantidad de personal de salud. El Peru posee el triste privilegio de ser el unico pais sudamericano considerado en este grupo.

Incremental yield of bronchial washing for diagnosing smear-negative pulmonary tuberculosis

OBJETIVO Avaliar o aumento do rendimento do diagnostico de tuberculose pulmonar mediante cultura de lavado bronquico em comparacao ao rendimento da cultura de escarro. METODOS Estudo realizado com 61 adultos da cidade de Lima, Peru, a partir de janeiro de 2006 a dezembro de 2007. Foi comparado o rendimento de culturas de escarro com o de esfregaco de bacilos acido-resistentes e cultura de amostras de lavado bronquico para diagnostico de tuberculose pulmonar, em casos suspeitos de tuberculose clinica, com esfregaco de escarro de bacilos acido-resistentes negativo. RESULTADOS Vinte e sete (IC95% 32;58) dos casos foram diagnosticados com tuberculose pulmonar de baciloscopia negativa. As amostras de lavabo bronquio detectaram 23 (95%; IC95% 72;99) dos casos de tuberculose pulmonar de baciloscopia negativa, comparados com 15 (IC95% 37;74) de cultura de escarro (p = 0.02). O diagnostico da tuberculose pulmonar mediante o uso do esfregaco de bacilos acido-resistentes e da cultura de lavado bronquico tiveram um rendimento adicional de 44% (IC95% 25;65) em relacao a cultura de escarro. CONCLUSOES Em funcao do contexto epidemiologico e dos recursos disponiveis, a broncoscopia deve ser adotada como parte de trabalho abrangente que otimize o diagnostico de tuberculose pulmonar de baciloscopia negativa e minimize riscos e custos.OBJECTIVE To assess the increased diagnostic yield for pulmonary tuberculosis using bronchial washing cultures compared with sputum cultures. METHODS Study conducted with 61 adults in Lima, Peru, from January 2006 to December 2007. The yield of sputum cultures was compared with the yield of acid-fast bacilli smears and cultures of bronchial washing for diagnosing pulmonary tuberculosis in suspected cases of clinical tuberculosis with negative acid fast bacilli sputum smears. RESULTS Twenty seven (95%CI 32;58) of the cases were eventually diagnosed with smear-negative pulmonary tuberculosis. Bronchial washing samples detected 23 (95%CI 72;99) of the smear-negative pulmonary tuberculosis cases compared with 15 (95%CI 37;74) for sputum cultures (p = 0.02). The incremental diagnostic yield of acid fast bacilli smear and culture of bronchial washing specimens over sputum culture was 44% (95%CI 25;65). CONCLUSIONS In function of the epidemiological context and the resources available, bronchoscopy should be deployed as part of a comprehensive work up that optimizes smear-negative pulmonary tuberculosis diagnosis and minimizes risk and costs.

Avaliação da utilidade diagnóstica da fibrobroncoscopia óptica na tuberculose pulmonar BAAR negativa na prática clínica de rotina

We evaluated the diagnostic yield of fiberoptic bronchoscopy for the diagnosis of smear-negative pulmonary tuberculosis in patients treated at a referral hospital in Lima, Peru. Of the 611 patients who underwent the procedure, 140 (23%) were diagnosed with tuberculosis based on the analysis of BAL samples. Being young and being male were significantly associated with positive cultures. In addition, 287 patients underwent post-bronchoscopic sputum smear testing for AFB, the results of which increased the diagnostic yield by 22% over that obtained through the analysis of BAL samples alone. We conclude that the analysis of BAL samples and post-bronchoscopic sputum samples provides a high diagnostic yield in smear-negative patients suspected of having pulmonary tuberculosis.

Performance of clinical prediction rules for diagnosis of pleural tuberculosis in a high-incidence setting

Diagnosis of pleural tuberculosis (PT) is still a challenge, particularly in resource‐constrained settings. Alternative diagnostic tools are needed. We aimed at evaluating the utility of Clinical Prediction Rules (CPRs) for diagnosis of pleural tuberculosis in Peru.

Manual liquid culture on simple Middlebrook 7H9 or MGIT for the diagnosis of smear-negative pulmonary tuberculosis

To compare the performance of liquid culture on simple Middlebrook 7H9 to the one of manual mycobacterial growth indicator tube (MGIT) and solid culture on Ogawa for the diagnosis of smear‐negative tuberculosis (SN‐TB) in a high‐burden, resource‐constrained setting.

Development of a clinical prediction rule for tuberculous meningitis in adults in Lima, Peru

Diagnosis of tuberculous meningitis (TM) is a challenge in countries with a high burden of the disease and constrained resources and clinical prediction rules (CPRs) could be of assistance. We aimed at developing a CPR for diagnosis of TM in a Latin American setting with high tuberculosis incidence and a concentrated HIV epidemic.