Latent tuberculosis infection among undergraduate medical students in Rio de Janeiro State, Brazil.

SETTING: Five medical schools in three cities with different tuberculosis (TB) incidence rates in Rio de Janeiro State, Brazil. OBJECTIVE: To estimate prevalence of and associated factors for latent tuberculosis infection (LTBI) among medical students. DESIGN: A cross-sectional survey was conducted among undergraduate students in pre-clinical, early and late clinical years from schools in cities with low (28/100,000), intermediate (63/100,000) and high (114/100,000) TB incidence rates. Information on socio-demographic profile, previous BCG vaccination, potential TB exposure, co-morbidity and use of respiratory protective masks was obtained. A tuberculin skin test (TST) was performed using the Mantoux technique by an experienced professional. A positive TST, defined as induration > or = 10 mm, was considered LTBI. RESULTS: LTBI prevalence was 6.9% (95%CI 5.4-8.6). In multivariate analysis, male sex (adjusted odds ratio [aOR] 1.8; 95% CI 1.1-3.0), late clinical years (aOR 1.9; 95% CI 1.01-3.5), intermediate TB incidence (aOR 4.3; 95% CI 1.3-14.6) and high TB incidence in the city of medical school (aOR 5.1; 95% CI 1.6-16.8) were significantly associated with LTBI. CONCLUSIONS: The higher prevalence of LTBI in late clinical years suggests that medical students are at increased risk for nosocomial Mycobacterium tuberculosis infection. The implementation of a TB control program may be necessary in medical schools, particularly in cities with higher TB incidence.

Pulmonary leptospirosis.

Leptospirosis is a worldwide zoonosis affecting wild and domestic mammals. It is most commonly transmitted to humans by indirect contact with infected animals. Vascular injury, mainly capillary damage, and hemorrhagic diathesis are prominent features in the affected organs. The most severe form of the disease presents with high fever, intense jaundice, hemorrhagic diathesis, hepatic and renal dysfunction, mental status changes, and cardiovascular collapse. Focal or diffuse areas containing alveoli filled with erythrocytes characterize the pulmonary involvement. These latter conditions, although unusual, are associated with significant mortality.

Paracoccidioidomycosis.

Paracoccidioidomycosis is a systemic infection caused by the dimorphic fungus Paracoccidioides brasiliensis. It is commonly an endemic disease in Latin America, but several cases have been reported outside this area, particularly now in this time of world globalization. Primary pulmonary infection occurs commonly in the first and second decades of life and usually has a benign, self-limited respiratory infection course. The adult chronic manifestation of the disease is usually the result of reactivation of quiescent lesions with diffuse lung infiltrates, predominately of the interstitial pattern, with or without involvement of various other organs. The finding of this disease in a patient is an important step for the large differential diagnosis of the interstitial lung diseases group.

Hyperoxia and lung disease.

Experimental studies and few human reports demonstrate that hyperoxia increases the level of reactive oxygen-derived free radicals and that these substances can produce oxidative cellular injury. However, available data suggest that the human lung is more resistant to hyperoxic oxidative damage than previously expected and demonstrate that absorption atelectasis is the most frequently pulmonary effect of inhalation of a high inspired oxygen fraction. Practically, the therapeutic use of high inspired oxygen fractions is limited to patients with acute lung injury and severe hypoxemia. Recent studies demonstrated that ventilator-induced lung injury is a more important cause of pulmonary damage in these patients than hyperoxic toxicity. New protective ventilatory strategies are associated with increased survival.

Pulmonary schistosomiasis.

Schistosomiasis is a very important infectious disease, and pulmonary involvement is not very rare. There may be two forms of pulmonary involvement, acute and chronic. The acute form usually occurs about 6 weeks after the infection (Katayama syndrome) and seems to be due to an allergic manifestation to the presence of Schistosoma spp. worm or eggs. The chronic form is more commonly seen in endemic areas and may cause pulmonary hypertension and cor pulmonale, pulmonary granulomatous schistosomiasis, and pulmonary arteriovenous fistulas. Recurrence of pulmonary infiltrations may appear after treatment. The globalization of the world with international travel makes it necessary for clinicians around the world to be aware of some "old" diseases from endemic areas of the globe.