Evaluation of Chest X-ray and Thoracic Computed Tomography in Patients with Suspected Tuberculosis

OBJECTIVE

To investigate if there is any correlation between positive findings detected by posterior-anterior (PA) chest radiograph and thoracic computerized tomography (CT) in cases with suspected lung tuberculosis (TB) due to positive tuberculin skin test (TST) results.

METHODS

This is a retrospective evaluation of the medical files of patients who visited the Department of Pediatrics, Istanbul University, Istanbul Faculty of Medicine from 2006, through 2011 as outpatients and had positive TST (>15 mm) results.

RESULTS

A total of 326 patients were included in the study; 45.7 % (n = 149) were girls, and the mean age was 9.0 ± 4.1 y (range: 1-17 y). In total, 14.4 % (n = 47) had TB findings, all of which were in the form of hilar lymphadenopathy. Among the 47 cases with TB findings in PA chest X-ray, 45 (95.7 %) also had findings in thoracic CT. Only 2 (4.3 %) patients had normal thoracic CT results although their PA chest X-ray results were positive.

CONCLUSIONS

Evaluation for pulmonary TB in children with positive isolated TSTs should be made primarily with PA chest X-ray. A routine thoracic CT scan is not necessary for asymptomatic patients with only hilar lymphadenopathy findings in PA chest radiographs.

Naïve-pooled pharmacokinetic analysis of pyrazinamide, isoniazid and rifampicin in plasma and cerebrospinal fluid of Vietnamese children with tuberculous meningitis

BACKGROUND

Among the various forms of TB, tuberculous meningitis (TBM) is the most severe, with about 30% mortality and 50% of survivors left with neurological sequelae. Children suffer more frequently from TBM than adults and outcomes are often poor due to difficulties in making the diagnosis and uncertainty regarding the best anti-tuberculosis drug regimen. The aim of this prospective study was to describe the pharmacokinetics of pyrazinamide, isoniazid and rifampicin in plasma and cerebrospinal fluid of children with tuberculous meningitis treated with the standard TBM regimen.

METHODS

We performed a prospective observational study of 100 consecutively treated children (≤ 15 years of age) with tuberculous meningitis in Ho Chi Minh City, Vietnam. Children were treated according to the 2006 WHO recommended pediatric treatment regimen consisting of isoniazid (5 mg/kg), rifampicin (10 mg/kg) and ethambutol (15 mg/kg) for 8 months, with the addition of pyrazinamide (25 mg/kg) for the first 3 months and streptomycin (15 mg/kg) for the first 2 months. Pyrazinamide, isoniazid and rifampicin concentrations were measured in plasma at day 14 and in cerebrospinal fluid (CSF) at 1 month by HPLC-UV. A naïve-pooled non-compartmental data analysis was used to describe the pharmacokinetic properties of drugs in the two-age groups of children ≤ 4 years or > 4 years of age.

RESULTS

Younger children, when compared to older children, presented a higher body weight-normalized clearance and volume of distribution, and lower median total plasma exposures for the three studied drugs with -14%, -22% and -16% for Pyrazinamide, Isoniazid and Rifampicin, respectively. In CSF, individual concentrations of isoniazid and pyrazinamide were comparable to that in plasma in both age groups; but rifampicin concentrations were lower than the minimum inhibitory concentration of susceptible bacteria in all but two children.

CONCLUSIONS

There is an age-dependent variation in the plasma and cerebrospinal fluid pharmacokinetics of rifampicin, isoniazid and pyrazinamide. The safety and efficacy of higher doses of rifampicin should be investigated for the treatment of childhood tuberculous meningitis.

Tuberculin skin test positivity without tuberculosis contact: A major challenge in childhood

AIM

Worldwide, tuberculin skin tests (TSTs) commonly give false positive results for those who had been given the Bacillus-Calmette-Guerin vaccine such as is routinely administered in Turkey. This study aimed to evaluate the patients referred to us who had positive TSTs despite lack of tuberculosis (TB) disease contacts.

METHODS

Between September 2011 and September 2012, 183 patients were prospectively evaluated for differential diagnosis of TST positivity despite lack of TB disease contact. They were then followed up by us to determine an accurate diagnosis.

RESULTS

Among our patients' most common symptoms indicating a need for TST were chronic cough, productive cough or sputum expectoration, and recurrent or persistent wheezing. Chest x-rays were taken of all patients, and the findings were noted. Interferon gamma release assays were performed on 75% of the patients, of which 96% were negative for TB. The most common final diagnoses were asthma (44%), allergic rhinitis (13%), bronchopneumonia (11%) and reactive lymphadenitis (6.5%). Further evaluations for TB were required of 36 patients, and TB disease was established in 12 of them (6.5%).

CONCLUSIONS

In patients who had had no known TB contact, the most common symptom indicating need for TST was chronic cough; the most common diagnoses were asthma and allergic rhinitis. Cavitary lesions, haemoptysis, persistent infiltration, pleural effusion and thoracic lymphadenopathy despite antibiotherapy should alert physicians to the possibility of TB.