Enfermedad pulmonar difusa asociada al consumo de tabaco / Smoking related interstitial lung disease: case report

ABSTRACT

The relationship between cigarette smoke and interstitial lung diseases (ILD) is not clear. Respiratory bronchiolitis (RB), usually found as an incidental histologic abnormality in otherwise asymptomatic smokers, is characterized by the accumulation of cytoplasmic golden-brown-pigmented macrophages within respiratory bronchioles. A small proportion of smokers have a more exaggerated response that, in addition to the bronchiole-centered lesions, provokes interstitial and air spaces inflammation and fibrosis extending to the nearby alveoli. This set of histologic changes is called RB-ILD, and it results in clinical symptoms. Desquamative interstitial pneumonia (DIP) is characterized by panlobular involvement, diffuse mild-to-moderate interstitial fibrosis, and massive alveolar filling with macrophages. It is well known that the histopathologic patterns of RB-IID and DIP may overlap, and that the key features for differentiating these disorders are the distribution and the extent of the lesions: bronchiolocentric in RB-IID and diffuse in DIP. It has been proposed that RB, RB-IID and DIP may be different components of the same histopathologic disease spectrum, representing various degrees of severity of the same process caused by chronic smoking, although this is still controversial. To illustrate the problem, we present the clinical case of a heavy-smoker patient with progressive dyspnea and radiographic pulmonary infiltrates suggesting of smoking related interstitial lung disease.

RESUMEN

La enfermedad pulmonar difusa asociada al consumo de tabaco no ha sido claramente definida, la bronquiolitis respiratoria (RB) es un hallazgo morfológico frecuente en fumadores asintomáticos, se caracteriza por la acumulación de macrófagos pigmentados en los bronquiolos respiratorios. Sólo una pequeña proporción de los sujetos fumadores presenta una respuesta inflamatoria exagerada que compromete el intersticio y espacio alveolar, lo cual corresponde a la bronquiolitis respiratoria asociada a enfermedad pulmonar difusa (RBIID), que se manifiesta por disnea de esfuerzos y tos. La neumonía intersticial descamativa (DIP) se caracteriza por compromiso panlobular, fibrosis intersticial discreta e infiltración masiva del espacio aéreo por macrófagos. El patrón histopatológico de RBIID y DIP se pueden sobreponer, siendo los principales elementos diferenciadores entre ambas entidades, la distribución y extensión de las lesiones: compromiso bronquiolo-céntrico en RBIID y difuso en DIP. Se ha planteado que la RB, RBIID y DIP pueden constituir diferentes fases de una misma enfermedad asociada al consumo de tabaco, lo cual aún es motivo de controversia. Con el propósito de ilustrar este problema, se presenta el caso clínico de un paciente fumador que consultó por disnea progresiva, tos e infiltrados pulmonares bilaterales sugerentes de enfermedad pulmonar difusa asociada al tabaquismo.