Pulmonary abnormalities as a result of exposure to Libby amphibole during childhood and adolescence-The Pre-Adult Latency Study (PALS).

BACKGROUND: The purpose of Pre-Adult Latency Study was to evaluate lung findings among adults who had been environmentally exposed to Libby Amphibole only during childhood and adolescence. METHODS: Recruitment was restricted to volunteers who attended primary and/or secondary school, lived in Libby, MT, prior to age 23 years for males and 21 years for females and subsequently left the area. Subjects completed exposure and respiratory questionnaires, underwent pulmonary function tests (PFTs), and chest CT scans. A Pleural Score was calculated for degree and extent of pleural thickening. Logistic regression and multivariate linear regression were used. RESULTS: Of the 219 who met inclusion criteria, 198 participated. Pleural thickening was found in 96 (48%) of 198 participants. In almost half of these, it was of the lamellar type, not generally seen in exposure to other asbestos. Environmental Libby amphibole exposure was associated with pleural thickening, and the likelihood of pleural thickening increased with the number of years lived in the area. An inverse association between Pleural Score and PFT was found, which remained significant for FVC and DLco after additional sensitivity analyses. CONCLUSIONS: Cumulative environmental exposure was associated with risk of pleural thickening. Among this cohort, quantitative measures of pleural thickening were associated with decreased PFT. Am. J. Ind. Med. 60:20-34, 2017. © 2016 Wiley Periodicals, Inc.

Rapid progression of pleural disease due to exposure to Libby amphibole: "Not your grandfather's asbestos related disease".

BACKGROUND: Residents and mine employees from Libby, Montana, have been exposed to asbestiform amphiboles from the vermiculite mine that operated in this location from the mid-1920s until 1990. Clinical observations show a different form of asbestos-related toxicity than other forms of asbestos. METHODS: Five illustrative cases from the Center for Asbestos-Related Diseases in Libby were selected. All had clear exposure histories, multiple follow-up visits, illustrative chest radiographic studies, serial pulmonary function tests, and sufficient length of follow-up to characterize disease progression. RESULTS: These cases developed increasing symptoms of dyspnea and chest pain, progressive radiological changes that were predominantly pleural, and a restrictive pattern of impaired spirometry that rapidly progressed with significant loss of pulmonary function. CONCLUSIONS: LA exposure can cause a non-malignant pleural disease that is more rapidly progressive and more severe than the usual asbestos-related disease.

Asbestos-associated mesothelial cell autoantibodies promote collagen deposition in vitro.

Fibrosis, characterized by excessive collagen protein deposition, is a progressive disease that can fatally inhibit organ function. Prolonged exposure to pathogens or environmental toxicants such as asbestos can lead to chronic inflammatory responses associated with fibrosis. Significant exposure to amphibole asbestos has been reported in and around Libby, Montana due to local mining of asbestos-contaminated vermiculite. These exposures have been implicated in a unique disease etiology characterized predominantly by pleural disorders, including fibrosis. We recently reported the discovery of mesothelial cell autoantibodies (MCAAs) in the sera of Libby residents and demonstrated a positive and significant correlation with pleural disease; however, a mechanistic link was not determined. Here we demonstrate that MCAAs induce pleural mesothelial cells to produce a collagen matrix but do not affect production of the pro-inflammatory cytokine tumor growth factor-ß. While autoantibodies commonly induce a pro-fibrotic state by inducing epithelial-mesenchymal transition (EMT) of target cells, we found no evidence supporting EMT in cells exposed to MCAA positive human sera. Although implicated in other models of pulmonary fibrosis, activity of the protein SPARC (secreted protein, acidic and rich in cysteine) did not affect MCAA-induced collagen deposition. However, matrix formation was dependent on matrix metalloproteinase (MMP) activity, and we noted increased expression of MMP-8 and -9 in supernatants of mesothelial cells incubated with MCAA positive sera compared to control. These data suggest a mechanism by which MCAA binding leads to increased collagen deposition through altering MMP expression and provides an important mechanistic link between MCAAs and asbestos-related, autoimmune-induced pleural fibrosis.

A primary care team approach to secondary prevention of work-related musculoskeletal disorders: Physical therapy perspectives.

BACKGROUND: Among work-related conditions in the United States, musculoskeletal disorders (MSDs) account for about thirty-four percent of work absences. Primary care physicians (PCPs) play an essential role in the management of work-related MSDs. For conditions diagnosed as work-related, up to seventeen percent of cases are PCP managed; within these conditions, up to fifty-nine percent are diagnosed as musculoskeletal. Negative factors in treatment success confronting PCPs include time constraints and unfamiliarity with work-related MSDs. A multidimensional team approach to secondary prevention, where PCPs can leverage the expertise of allied health professionals, might provide a useful alternative to current PCP practices for the treatment of work-related MSDs. OBJECTIVE: Provide the structure of and rationale for an "extended care team" within primary care for the management of work-related MSDs. METHODS: A systematic literature search, combining medical subject headings and keywords, were used to examine eight peer-reviewed literature databases. Gray literature, such as government documents, were also used. RESULTS: An extended care team would likely consist of at least nine stakeholders within primary care. Among these stakeholders, advanced practice orthopedic physical therapists can offer particularly focused guidance to PCPs on the evaluation and treatment of work-related MSDs. CONCLUSIONS: A multidimensional approach has the potential to accelerate access and improve quality of work-related outcomes, while maintaining patient safety.

Association of low FVC spirometric pattern with WTC occupational exposures.

BACKGROUND: A reduced forced vital capacity without obstruction (low FVC) is the predominant spirometric abnormality reported in workers and volunteers exposed to dust, gases, and fumes at the World Trade Center (WTC) disaster site in 2001-2002. While low FVC has been associated with obesity and metabolic syndrome, its association with WTC occupational exposures has not been demonstrated. We estimated the prevalence of this abnormality and examined its association with WTC exposure level. METHODS: Longitudinal study of the relation between arrival at the WTC site within 48 h and FVC below the lower limit of normal (FVC < LLN, with normal FEV1/FVC ratio) at any time in 10,284 workers with at least two spirometries between 2002 and 2018. Logistic regression and linear mixed models were used for the multivariable analyses. RESULTS: The prevalence of low FVC increased from 17.0% (95% CI 15.4%, 18.5%) in June 2003, to 26.4% (95% CI 24.8%, 28.1%) in June 2018, and exceeded at both times that of obstruction. The rate of FVC decline was -43.7 ml/year during the study period. In a multivariable analysis adjusting for obesity, metabolic syndrome indicators, and other factors, early arrival at the WTC disaster site was significantly associated with low FVC, but only among men (ORadj = 1.29, 95% CI 1.17, 1.43). Longitudinal FVC rate of decline did not differ by WTC site arrival time. CONCLUSIONS: Among WTC workers, the prevalence of low FVC increased over a 16-year period. Early arrival to the WTC disaster site was significantly associated with low FVC in males.

Potential for diffuse parenchymal lung disease after exposures at World Trade Center Disaster site.

OBJECTIVE: The diffuse parenchymal lung diseases (DPLDs) are a heterogeneous group of disorders that result from damage to the lung parenchyma. While the cause of most DPLDs remains unknown, extensive epidemiological and experimental evidence has linked exposure to environmental toxins to the pathogenesis of some of those diseases. The purpose of this review is to examine the potential relation between exposure to toxins released from the World Trade Center (WTC) collapse on September 11th, 2001 and the development of DPLD based on published evidence up to date. METHODS: We examine such evidence from two points of view, (1) exposure, and (2) histopathogenesis. EXPOSURE: Analyses of WTC-dust and particle size demonstrate that some portion of the dust was composed of particles small enough to penetrate deep into the lungs, reaching distal airways and alveoli. The presence of such particles has been confirmed in studies of induced sputum and bronchoalveolar lavage in WTC-exposed firefighters. Histopathogenesis: In vitro and animal experiments and patient evidence suggest that WTC dust is capable of inducing a pulmonary interstitial inflammatory response. RESULTS: To date, there have been limited clinical reports documenting the development of diffuse parenchymal responses following exposure to WTC dust. No single common pathologic response has been described. The one common denominator in the reports is that the individuals who developed disease were heavily exposed either during the disaster or during the initial 2-to-3 days following the disaster. CONCLUSION: DLPDs are probably associated with heavy or extended exposure to the toxins released at the WTC disaster site. Coupled with the historical experience with exposures to occupational toxins this mandates continued long-term clinical observation of this cohort.

Libby Amphibole Disease: Pulmonary Function and CT Abnormalities in Vermiculite Miners.

OBJECTIVE: This article describes radiologic and pulmonary function findings among miners exposed to Libby amphibole. Computed tomography (CT) permits the detection of the characteristic thin, lamellar pleural thickening (LPT). METHODS: Individuals who worked at the mine for a minimum of 6 months had chest CT and pulmonary function tests. RESULTS: Pleural thickening was noted in 223 (87%) of the 256 miners, parenchymal abnormalities in 49 (19%). LPT, found in 151 (68%), was associated with low values of forced vital capacity and diffusion capacity and significantly lower values in all pulmonary function tests when associated with parenchymal abnormalities. CONCLUSION: Eighty-seven percent of miners exposed to Libby Amphibole had pleural abnormalities on CT. LPT alone, and more so with parenchymal abnormalities, resulted in decreased pulmonary function. The importance of this easily missed LPT is demonstrated by its high frequency and significant functional effects.

Case report: silicatosis in a carpet installer.

CONTEXT: Chronic exposure to talc in the course of carpet installation can result in pneumoconiosis. CASE PRESENTATION: We present a case of a young carpet installer who was diagnosed with silicatosis of the lung. Review of occupational history revealed that the patient had been working as a carpet installer for approximately 15 years, since he was 15 years of age. The patient was exposed to talc in the course of his work. DISCUSSION: Exposure to talc in the course of carpet installation has not been reported as a possible cause of pneumoconiosis. In this article we review different causes of silicatosis and discuss chronic exposure in the course of carpet installation and development of pneumoconiosis. In addition, we also review the relevance of mycobacterial infection in cases of silicosis and silicatosis. RELEVANCE TO CLINICAL OR PROFESSIONAL PRACTICE: Exposure to talc in the course of carpet installation should be added to conditions that can cause pneumoconioses, specifically silicatosis of the lung.

Multiple pathway asbestos exposure assessment for a Superfund community.

Libby, MT, USA, was the home to workers at a historical vermiculite mining facility and served as the processing and distribution center for this industrial product that was contaminated with amphibole asbestos. Several pathways of environmental asbestos exposure to the general population have been identified. The local clinic and health screening program collects data from participants on past occupational and environmental exposures to vermiculite and asbestos. Health studies among this population have demonstrated associations between amphibole exposure and health outcomes, but critical questions regarding the nature and level of exposure associated with specific outcomes remain unanswered. The objective of this study was to develop a comprehensive exposure assessment approach that integrates information on individuals' contact frequency with multiple exposure pathways. For 3031 participants, we describe cumulative exposure metrics for environmental exposures, occupational exposures, and residents' contact with carry-home asbestos from household workers. As expected, cumulative exposures for all three occupational categories were higher among men compared with women, and cumulative exposures for household contact and environmental pathways were higher among women. The comprehensive exposure assessment strategies will advance health studies and risk assessment approaches in this population with a complex history of both occupational and environmental asbestos exposure.

Gasimetría arterial y EPOC (II): relación entre valores de gasimetría arterial y estudios de función pulmonar en pacientes con enfermedad pulmonar obstructiva crónica a nivel de Bogotá

En un artículo anterior se presentó un estudio de correlación entre variables espirométricas y gasimétricas en una población de pacientes con enfermedad pulmonar obstructiva crónica (EPOC) a nivel de Bogotá. En el presente trabajo se informa una serie con mayor número de casos (85) y se amplían las observaciones, haciendo correlaciones entre presión arterial de oxígeno (PaO2), dióxido de carbono (PaCO2) y volumen en el primer segundo de la espiración forzada (VEF1). Se confirma el hallazgo de correlación estadísticamente significativa entre Pa)2 y VEF1 (r:.45, P<0.001). Igualmente se encontró correlación significativa entre PaCO2 y VEF1 (r:-.51, P<0.0001). El VEF1 en pacientes con EPOC es un índice adecuado entonces, no unicamente de la mecánica ventilatoria sino, indirectamente, del intercambio gaseoso a nivel alveolar, y permite establecer recomendaciones de práctica de gasimetría arterial a pacientes con esta enfermedad pulmonar. El hallazgo de correlaciones significativas no implica relación de causalidad, y no se puede afirmar que el VEF1 sea la única variable de la cual dependen las alteraciones gasimétricas en pacientes con EPOC

Diferencia alvéolo-arterial de oxígeno en pacientes con enfermedad pulmonar obstructiva crónica e hipoventilación alveolar: un índice poco confiable

De acuerdo con las enseñanzas convencionales, el cálculo de la diferencia entre la presión alveolar y arterial de oxígeno D(AaO2) es útil para diferenciar entre hipoxemia arterial causada por hipoventilación alveolar e hipoxemia arterial secundaria a hipoventilación alveolar complicada con otras anormalidades del intercambio gaseoso. Sin embrago, estudios recientes demuestran que en pacientes con enfermedad pulmonar obstructiva crónica con hipoventilación alveolar, el cálculo de la D(AaO2) puede mostrar cifras normales en presencia de alteraciones importantes de la relación ventilación/perfusión. El propósito del presente estudio fue investigar la presencia de estos hallazgos en pacientes con enfermedad pulmonar obstructiva crónica residentes a altitudes como las de la ciudad de Bogotá (2.500 mts sobre el nivel del mar). Se analizaron 96 muestras de gasimetría arterial practicadas como parte del estudio de la evolución de la enfermedad en estos pacientes,estando en estado estable y ambulatorios. Veintiséis (26) de ellas mostraron valores de presión arterial de CO2 mayores del límite máximo normal aceptado para Bogotá (36 mmHg, hipoventilación alveolar). Quince (15) tenían D(AaO2) dentro límites normales (menor de 20 mmHg). En todas las muestras se calcularon, además, los valores de la mezcla (Qva/Qt) y del cortocircuito veno-arterial (Qs/Qt), que mostraron cifras aumentadas en la totalidad de los casos. Se concluye que el cálculo de la diferencia alvéolo-arterial de oxígeno puede inducir errores si se utiliza como único índice para explicar los mecanismos de hipoxemia en pacientes con enfermedad pulmonar obstructiva crónica y retención de CO2, en quienes se impone la necesidad de utilizar indicadores diferentes para el análisis de la gasimetría arterial. Se pone de presente la relativa poca frecuencia de retención de CO2 en pacientes con enfermedades obstructivas crónica (25 por ciento delos casos) y se hacen algunas reflexiones sobre los mecanismos de intercambio gaseoso en pacientes con esta afección pulmonar.

Difusión pulmonar de monóxido de carbono en individuos sanos no fumadores en Santafé de Bogotá (2.640 m de altura sobre el nivel del mar)

Con el propósito de comparar las ecuaciones de predicción para la prueba de la difusión pulmonar con monóxido de carbono en individuos sanos de Santafé de Bogotá, con las publicadas previamente en la literatura médica y las correciones propuestas para altura sobre el nivel del mar, se presenta una serie de 40 mediciones realizadas en población sana no fumadora, habituada a la altura de esta ciudad. Se encontraron valores de difusión pulmonar de monóxido de carbono mucho que los esperados a nivel del mar, incluso aplicando las ecuasiones de correción publicadas. Esta es la primera serie que se pública sobre mediciones realizadas a niveles tan altos sobre el mar. En vista de los hallazgos, se propone la realización de un estudio cooperativo con el fin de reunir una muestra más representativa y establecer la que sería la ecuación patrón de comparación de la capacidad de difusión de monóxido de carbono a nivel de Santafé de Bogotá.

Manejo del empiema bacteriano crónico

Presentamos nuestra experiencia en el manejo del empiema bacteriano crónico en el Hospital Militar Central de Santafé de Bogotá. Esta serie de casos incluye 30 pacientes tratados en el hospital entre 1985 y 1990. Todos los pacientes eran adultos jóvenes, de sexo masculino, en servicio militar activo. Todos tenían un diagnóstico previo de neumonía bacteriana y habían sido tratados en sus respectivos centros locales de atención médica. Los pacientes fueron trasladados a nuestro servicio debido al deterioro progresivo de su estado clínico y a su fiebre continua. Al examen físico así como con la radiografía de tórax evidenciaron la presencia de derrame pleural, y el aspirado pleural fue francamente purulento en todos los casos. El protocolo de manejo consistió en toracentesis inicial intentando remover el máximo posible de líquido pleural. El uso de antibióticos se descontinuó tan pronto como los pacientes fueron admitidos en el servicio. En caso de reaparición de la fiebre, se realizaban nuevas toracentesis entre el segundo y cuarto días luego del procedimiento inicial. Ninguno de los pacientes fue tartado con totacostomía cerrada ni con cirugía torácica. Los pacientes fueron dados de alta luego de la mejoría de los sintomas iniciales. Practicamos toracentesis repetidas ambulatoriamente, en caso de reaparición de fiebre o dolor torácico. Durante el manejo ambulatorio ninguno necesitó más de tres a cinco de estos procedimientos repetidos. El curso final en todos los casos fue la mejoría clínica. Se obtuvo normalización completa de la radiografía en 21 de los 30 pacientes. Los otros mostraron secuelas radiográficas menores, tales como borramiento del ángulo costofrénico o engrosamiento pleural. Sin embargo, ninguno mostró decremento funcional en la realización de sus actividades diarias, así como en tolerancia al ejercicio. Nuestra experiencia indica que el manejo no invasivo del empiema crónico en adultos jóvenes y por demás sanos, puede ser efectivo en algunos casos.

Fracción de eyección ventricular en pacientes con enfermedad pulmonar obstructiva crónica irreversible a la altura de Bogotá

Se presenta un estudio utilizando el método de angiocardiografía radionuclear de equilibrio (MUGA), para la valoración de la fracción de eyeccion ventricular derecha (FEVD) en pacientes con enfermedad pulmonar obstructiva crónica (EPOC). Aunque no se encontró una correlación estadísticamente significativa entre la FEVD y el grado de severidad de la función ventilatoria establecido por prubas de función pulmonar y gasimetría arterial, se observó que ésta tendía a disminuir a medida que la función respiratoria se deterioraba progresivamente en el grupo de pacientes estudiados. En especial en el grupo con volumen espiratorio forzado en el primer segundo menor de 1 lt/sg y con una presión arterial de CO2 mayor de 36 mm Hg a nivel de Bogotá, se encontraron altos índices de correlación entre la FEVD y los parámetros de funcion pulmonar y gasimetría arterial. Igualmente se encontró que el valor de la FEVD era menor en pacientes con cuadro clínico de cor pulmonar que en el grupo restante. En general no se encontró un compromiso de la fracción de eyección del ventrículo izquierdo (FEVI) en ninguno de los grupos estudiados, aun aquellos con un mayor compromiso de la función cardiopulmonar. Se plantea la utilidad de la FEVD como índice independiente en la valoración de la gravedad clínica del paciente con EPOC