ABSTRACT
Abstract Background: Clinically evident interstitial lung disease (ILD) affects between 10 and 42% of the patients with rheumatoid arthritis (RA). Airway involvement seems to be even more common. Most of the available evidence comes from studies performed in established RA patients. The aim of our study was to know the prevalence of non-diagnosed lung disease (airway and interstitial involvement) in patients with early RA and look for associated factors. Methods: We designed an observational, multicenter, cross-sectional study, and included patients with RA of less than two years since diagnosis. We performed a structured questionnaire, HRCT and lung functional tests looking for lung disease, together with joint disease evaluation. We analyzed which variables were associated with the presence of lung disease on HRCT. Results: We included 83 patients, 83% females. The median (IQR) of time since RA diagnosis was 3 (1-6) months. In the HRCT, 57 patients had airway compromisea (72%), and 6 had interstitial abnormalities (7.5%). The most common altertion found in lung functional tests was a reduced DLCO (14%). The presence of at least one abnormality in the physical exam was associated with lung involvement on HRCT [13 (21.6%) vs 0 (0%); p = 0.026]. Also, patients with lung involvement presented significantly lower values of FVC% and DLCO%, and higher values of RV/TLC. No variable related to joint involvement was found associated with alterations in HRCT. Conclusion: Our study shows that a large proportion of early RA patients has abnormal findings in HRCT. Further studies are required to confirm these findings.
ABSTRACT
El déficit de alfa-1 antitripsina (AAT) es una condición hereditaria rara y raramente diagnosticada en todo el mundo, incluida Argentina. El infradiagnóstico es fundamentalmente debido a que muchos médicos desconocen su existencia, diagnóstico y tratamiento. Por ello, la Asociación Argentina de Medicina Respiratoria encomendó a un grupo de expertos la elaboración de la presente normativa. La AAT es una glicoproteína secretada por el hígado, muy abundante en sangre, tejidos y fluidos corporales, cuya función principal consiste en inhibir la elastasa del neutrófilo y otras serin proteasas, confiriendo al suero humano más del 90% de su capacidad antiproteasa. El déficit de AAT deriva de mutaciones del gen de la SERPINA1, y se manifiesta clínicamente por enfisema pulmonar, cirrosis hepática y, con menor frecuencia, por paniculitis, vasculitis sistémicas y posiblemente otras enfermedades. El déficit grave de AAT afecta mayoritariamente a individuos de raza caucasiana y tiene su máxima prevalencia (1:2.000-1:5.000 individuos) en el norte, oeste y centro de Europa. En EEUU y Canadá, la prevalencia es de 1: 5.000-10.000, y es 5 veces menor en países latinoamericanos, incluida Argentina, donde se estima que puede haber unos 18.000 individuos con genotipos deficientes graves SZ y ZZ, la inmensa mayoría sin diagnosticar. Sospechar la enfermedad resulta clave para medir la concentración sérica de AAT y completar el diagnóstico con la determinación del fenotipo o genotipo ante concentraciones bajas. La detección de casos permite la puesta en práctica del consejo genético, el chequeo de familiares consanguíneos y, en casos seleccionados, la aplicación de terapia sustitutiva.
The alpha-1 antitrypsin (AAT) deficiency is a rare hereditary condition which is rarely diagnosed in the world, including Argentina. Underdiagnosis is mainly due to lack of knowledge of its diagnosis and treatment by many physicians. For this reason, the Argentine Association of Respiratory Medicine convened a group of experts to develop the present guidelines. AAT is a glycoprotein secreted by the liver; it reaches high levels in blood, body tissues and fluids. Its main function is to inhibit the neutrophil elastase and other serum proteases providing 90% of human serine antiprotease activity. The AAT deficiency is produced by mutations of the SERPINA1 gene. Its clinical manifestations are pulmonary emphysema, liver cirrhosis, and less often panniculitis, systemic vasculitis and possibly other conditions. The severe AAT deficiency affects mainly Caucasian individuals. The highest prevalence, ranging from 1 in 2000 to 1 in 5000 population is observed in northern, western and central Europe. In the USA and Canada, the prevalence varies from 1 in 5000 to 1 in 10000 population. It is 5 times less frequent in Latin American countries. It is estimated that in Argentina there may be 18000 cases with severe deficiency of SZ y ZZ genotypes, most of them undiagnosed. It is crucial to suspect the disease in order to measure the serum AAT concentration, and, if the concentrations are low, to confirm the diagnosis with the phenotype or genotype determinations. Case detection allows genetic advice, control of blood-related relatives and in selected cases, replacement therapy.