[Description of tuberculosis outbreak and usefulness of mediastinal ultrasound]

OBJECTIVES

Describe a school outbreak of tuberculosis and compare the features with other outbreaks. Propose mediastinal ultrasound as an aid in its diagnosis and monitoring.

PATIENTS AND METHODS

Retrospective descriptive study of the transmission of tuberculosis infection in a micro-epidemic. Infection criteria: Mantoux ≥ 5mm, asymptomatic patient, with normal radiological, microbiological and analytical studies. Disease criteria: Mantoux ≥ 5mm and any of the above pathological studies. Mediastinal ultrasound was used as a complementary method of chest radiography (CXR). Computed tomography (CT) as the combined result of ultrasound and CXR was inconclusive.

RESULTS

Seventeen out of 412 students were infected and 16 with tuberculosis disease. In addition, 4 out-school contacts were diagnosed of tuberculosis.

CLINICAL MANIFESTATIONS

one erythema nodosum, one Henoch-Schönlein purpura, twelve with cough and fever nine. CXR results in patients: 3 normal, 7 inconclusive, and 10 with the following findings: 2 pneumonia, 2 pulmonary atelectasis, 2 primary complexes, 4 patients only with lymphadenopathy. All patients with normal or indeterminate CXR showed mediastinal lymphadenopathy visualized on ultrasound but 3 demonstrated by CT. Microbiological isolation: 6 cases (31%).

CONCLUSIONS

The number of infected patients was higher compared to other outbreaks There is great variability in the diagnostic approach to tuberculosis micro-epidemics. It is complex to differentiate between infection and disease. The clinical, laboratory and CXR are nonspecific. There are patients with normal CXR, pathological ultrasound and microbiological isolation. Mediastinal ultrasound can play an important role in the diagnosis and management of tuberculosis disease.