[Extrinsic allergic alveolitis. Clinical experience at the Instituto National de Enfermedades Respiratorias (INER)]. / Alveolitis alérgica extrínseca. Experiencia clínica del INER.

Extrinsic allergic alveolitis is an interstitial lung disease caused by exposure to a variety of inhaled antigens. In Mexico, the most frequent form is due to the inhalation of avian antigens, markedly pigeon proteins. Depending on type and time exposure, the disease presents different clinical forms usually characterized by progressive dyspnea, ground glass or reticulonodular images on chest x rays, a restrictive functional pattern, rest hypoxemia worsening with exercise, and increase of T lymphocytes in bronchoalveolar lavage with an inversion in the helper/suppressor ratio. In this paper, we discuss a 15-year experience with this pathological problem in Mexico, emphasizing the differences with this disorder in Caucasian populations. Generally, our patients display a chronic form of the disease, which evolves to fibrosis in about one-half of the patients. In this sense, the diagnostic, prognostic, and therapeutic focusing exhibit different elements, and thus the development of clinical and basic research is strongly required.

Risk indicator of dust exposure and health effects in cement plant workers.

A frequent practical problem of research in developing countries is the lack of reliable records on occupational hazards. To improve this situation, this article suggests and evaluates a two-phase method for estimating particle exposure. The first phase uses the focal group, or homogeneous group, technique to reconstruct the production process and estimate the level of dust exposure. The second phase applies the technique of individual history of exposure to hazards at work, an index that accumulates current and previous exposure. This method was introduced in a Portland cement plant to assess the dust-exposure levels of workers and to evaluate its usefulness in the association between estimated exposure levels and the frequency of health effects--particularly respiratory effects--that occurred as a result of such exposures. The results obtained from the analysis of the production process and of the exposure levels determined by the cement workers showed that it is possible to reconstruct the history of exposure to cement dust during each worker's occupational history. The results also showed that estimated exposure is related to respiratory damage; higher exposure resulted in more serious diseases. This supports the usefulness of the suggested methodology.

[Validation of a visual analog scale to measure dyspnea in patients with diffuse interstitial lung disease]. / Validación de una escala análoga visual para medir disnea en pacientes con enfermedad pulmonar intersticial difusa.

In order to validate a form of measuring dyspnea, a visual analog scale (VAS) was applied to 27 patients with different types of interstitial lung diseases (ILD). The test was done in two days with an interval of one month (dyspnea1 and dyspnea2). Additionally, the forced vital capacity (FVC) was obtained on these occasions (FVC1, FVC2). Nineteen patients with a recent diagnosis of ILD (RD) and eight with a previous diagnosis of ILD (PD) were included. In patients with RD, dyspnea1 correlated with FVC1 (r = -0.66, p < 0.01). A month after the initial treatment with steroids, dyspnea (mean +/- SD) decreased from 38 +/- 25 mm to 17 +/- 19 mm (p < 0.03), while the FVC increased from 1086 +/- 464 mL to 1350 +/- 536 mL (p < 0.05). Likewise, dyspnea2 correlated with FVC2 (r = -0.47, p < 0.05). As expected, patients with PD did not exhibit significant changes in the analysis of dyspnea on the second evaluation. The inter-observer coefficient of variation for the 8 patients with PD was of 5% and 9% for the first and second evaluations respectively, while the intraclass correlation coefficient was 0.92 and 0.91 respectively. The intra-observer coefficient of variation of two different observers was of 15% and 16% respectively, while the intraclass correlation coefficient was 0.69 and 0.62 respectively. These results suggest that the use of a VAS might be useful for the initial evaluation and during the follow-up of patients with ILD.

Relationship between lung inflammation or fibrosis and frequency dependence of compliance in interstitial pulmonary diseases.

In order to find a physiological parameter which discriminates between the predominance of inflammation or fibrosis, pulmonary function tests and open lung biopsy were performed on 19 patients with interstitial lung disease. Our results showed that the only test which may be useful is the dynamic lung compliance/quasi-static lung compliance (Cdyn/Cst) index. In this context, values equal or lower than 0.85 of the Cdyn/Cst index indicate that inflammation predominates, and values higher than 0.85 suggest that interstitial fibrosis is the main feature.