Albert Miller

Ventilatory failure due to asbestos pleurisy

Seven patients are described who had a distinctive syndrome of chest wall restriction caused by asbestos-induced pleural fibrosis. All had severe dyspnea and predominant pleural disease on radiographic examination, with pulmonary function findings of reduced vital capacity, total lung capacity (measured in five patients), and maximal voluntary ventilation. Five patients had ventilatory failure with carbon dioxide retention; four of these have died and one is close to death. Examination of the thoracic organs in five patients showed minimal or no parenchymal fibrosis in three and less severe involvement of the parenchyma than of the pleura in the remaining two. Neoplasms were suspected in three patients because of extension of the pleural fibrosis into the lung. Two of these patients had pleural uptake of 67-gallium citrate attributable to the inflammatory reaction. With the increasing duration since onset of exposure in the nine million workers who have been exposed to asbestos, as well as in other exposed persons, it is expected that additional cases of ventilatory failure caused by asbestos-induced pleural fibrosis will be encountered.

DECREASE IN VITAL CAPACITY IN PCB-EXPOSED WORKERS IN A CAPACITOR MANUFACTURING FACILITY*

Pulmonary function was evaluated in 243 workers exposed to PCB in the manufacture of capacitors. Mean employment was greater than 15 years. Thirty-four of the workers (14%) were found to have a reduced Forced Vital Capacity (FVC less than 80% of Morris predicted). Of the 34 with reduced FVC, 27 (80%) demonstrated a restrictive pattern of impairment (FEV1/FVC greater than 0.7). Only one of these 27 workers had an abnormal chest roentgenogram (greater than or equal to 1/0 by ILO UC Classification of Radiographs of Pneumoconioses). These findings are of interest in view of recent experimental data indicating the accumulation of PCBs and PCB metabolites in lung tissue (Brandt and Jansson). Restrictive spirometric impairment with no radiographic change is unusual in occupational exposure.

Interaction of asbestos, age, and cigarette smoking in producing radiographic evidence of diffuse pulmonary fibrosis

The study of 3,472 chest x-rays from four populations with different levels of exposure to asbestos and with different cigarette smoking histories shows that smoking in the general population does not produce pulmonary fibrosis recognizable on chest radiography. In the general population of Michigan, the prevalence of a radiographic pattern of fibrosis was 0.5 percent in men and 0.0 percent in women. In a Long Beach, California census tract population, the prevalences were 3.7 percent for men and 0.6 percent for women. Similarly, cigarette smoking does not enhance fibrosis when the exposure to asbestos has been as light as that in households of shipyard workers. Asbestosis was recognized in 6.6 percent of 137 shipyard workers wives who have never smoked and 7.6 percent of 132 who had ever smoked. Cigarette smoking and asbestos appear to be synergistic in those occupationally exposed to asbestos (as insulators), since 7.2 percent of 97 nonsmokers and 20.5 percent of 316 ever-smokers showed fibrosis. This apparent synergy was also found in shipyard workers up to age 70 with 31 percent of nonsmokers and 43.3 percent of ever-smokers having fibrosis. There were increases of approximately 10 percent in the prevalence of fibrosis in cigarette smokers and nonsmokers for each decade after age 40.

CHANGES IN PULMONARY FUNCTION IN WORKERS EXPOSED TO VINYL CHLORIDE AND POLYVINYL CHLORIDE

To determine whether occupational exposure to vinyl chloride gas and polyvinyl chloride dust is associated with changes in pulmonary function, spirometry and maximum expiratory flow-volume curves were obtained in 348 workers in a VC polymerization plant. The major finding was diminution in air flow in 200 workers (57.5 percent). This abnormality correlated with age and duration of exposure. A relationship with smoking was noted only in younger workers with exposures of less than 10 years. When age exceeded 40 years or exposure 20 years, prevalence of this impairment was similar in smokers and nonsmokers, suggesting that occupational or other environmental factors were operative.

Measuring lung volumes in advanced asbestosis : comparability of plethysmographic and radiographic versus helium rebreathing and single breath methods

Total lung capacity was measured in 16 workers with pulmonary asbestosis using four standard methods: body plethysmography, radiographic lung area, helium dilution by multiple breath and by single breath (alveolar volume). All men had irregular opacities of ILO profusion category 2/1 or greater and four had pleural plaques in addition. The radiographic and plethysmographic methods produced virtually identical mean values for TLC of 7.52 l and 7.64 l and for RV of 4.06 l and 4.32 l and all values were larger than those by helium dilution. The closed circuit helium dilution method systematically underestimated TLC with a mean of 5.89 l as did single breath helium dilution with a mean of 6.39 l. These men had a larger mean RV/TLC, measuring 56.9% by body plethysmography and 54.6% by X-ray area than by the rebreathing dilutional method which was 43.8%. Air trapping within a normal TLC which characterizes asbestosis is revealed by radiographic and plethysmographic methods but concealed by gas dilution methods. Use of the latter is at least partly responsible for the impression that asbestosis is a restrictive disease.

Malignant pleural mesothelioma presenting as spontaneous pneumothorax: a case series and review

BACKGROUNDnMalignant pleural mesothelioma (MPM) is thought to arise from the mesothelial cells that line the pleural cavities. Most patients initially experience the insidious onset of chest pain or shortness of breath, and it rarely presents as spontaneous pneumothorax.nnnCASE REPORTSnWe report four patients who presented in this manner. Three of the patients were exposed to asbestos directly or indirectly at shipyards during World War II; the fourth was exposed as an insulators wife. Two of our cases were not recognized to have MPM on histologic examination at first thoracotomy and remained asymptomatic for 12 and 22 months, respectively. In none of the patients described herein, was spontaneous pneumothorax the cause of death.nnnCONCLUSIONSnSince many people were exposed to asbestos during and after World War II, spontaneous pneumothorax in a patient with the possibility of such exposure should raise the suspicion of malignant pleural mesothelioma.

The interpretation of spirometric measurements in epidemiologic surveys

Abstract Spirometry is a fundamental tool in pulmonary epidemiology. Published standards provide specific information on instrumentation, techniques of testing, calculation of results, and physiologic mechanisms. They do not provide guidelines on how to interpret the test results once obtained, e.g., on such questions as which predicted values to use, what value is abnormal, how many people in the general population are likely to be abnormal? It is with these questions that this paper is concerned. Standard normal values in wide use are not ideal but should be utilized for all subgroups of the population investigated, as well as for the comparison population. Conventional definitions of abnormality lack statistical rationale and result in many false-positive and some false-negative results. This is especially true for fixed ratios such as forced expiratory volume (−1 sec)/forced vital capacity abnormality (a value below the lower limit of normal) means disease . The distribution of values (including the mean and standard deviation) should be used to assess epidemiologic risk factors. Prevalence rates separate abnormal from normal subjects. Such data may be used to identify those requiring preventive intervention, medical care, or compensation. Pathogenic mechanisms can be more easily isolated when abnormal subjects are separated from the majority of normal. Frequencies of spirometric abnormality in standard or normal populations serve as a reference to compare rates of similar abnormality in a population under investigation.

Baclofen-Induced Bronchoconstriction

OBJECTIVE: To report the occurrence of acute bronchospasm in one asthmatic patient and increased bronchial reactivity in another following the administration of a single dose of oral baclofen. CASE SUMMARY: On two separate occasions, a 46-year-old asymptomatic asthmatic man developed dyspnea and chest tightness one hour after the ingestion of baclofen 40 mg. Pulmonary function studies revealed a significant decrease in airflow relative to baseline. A 33-year-old asymptomatic woman with a history of exercise-induced dyspnea and wheezing displayed bronchial hyperresponsiveness to inhaled methacholine 2 hours after ingesting 40 mg of baclofen. The patient had had a negative methacholine challenge test 72 hours earlier. DISCUSSION: The gamma-aminobutyric acid-agonist baclofen has been shown to reduce airway responsiveness to various bronchoconstricting agents in animal studies. The etiology of this seemingly paradoxical response in two patients is unclear, but may offer insight into the neurally mediated airway constriction that occurs in asthma. CONCLUSIONS: Clinicians should be aware of the possibility of baclofen-induced bronchospasm, especially in asthmatic patients.

Pulmonary infarction secondary to pulmonary embolism: An evolving paradigm: Pulmonary embolism and infarction

Pulmonary infarction (PI) from pulmonary embolism (PE) remains an entity of unclear aetiology. PI has been thought to occur in elderly patients with cardiopulmonary disease. We hypothesize younger patients without cardiopulmonary comorbidities are at highest risk. Our study aims to characterize PI clinically and radiographically, determine associated risk factors and determine their clinical significance.

Association Between CD4 + , Viral Load, and Pulmonary Function in HIV

PurposeThe antiretroviral therapy era has shifted the epidemiology of HIV-associated diseases, increasing the recognition of non-infectious pulmonary complications secondary to HIV. We aimed to determine the association between CD4+, viral load, and pulmonary function in individuals with uncontrolled HIV, and determine how changes in these parameters are associated with pulmonary function longitudinally.MethodsThis is a retrospective observational study of individuals with HIV who underwent pulmonary function testing in an urban medical center between August 1997 and November 2015.ResultsOf the 146 participants (mean age 52xa0±xa010xa0years), 49% were Hispanic, 56% were men, and 44% were current smokers. CD4+ <200xa0cells/μl was associated with significant diffusion impairment compared to CD4+ ≥200xa0cells/μl (DLCO 56 vs. 70%, pxa0=xa0<0.01). VL (viral load) ≥75xa0copies/ml was associated with significant diffusion impairment compared to VL <75xa0copies/ml (DLCO 60 vs. 71%, pxa0=xa0<0.01). No difference in FEV1, FEV1/FVC, or TLC was noted between groups. In univariate analysis, CD4+ and VL correlated with DLCO (rxa0=xa0+0.33; pxa0=xa0<0.01; rxa0=xa0−0.26; pxa0=xa0<0.01) and no correlation was noted with FEV1, FEV1/FVC, or TLC. Current smoking and history of AIDS correlated with DLCO (rxa0=xa0−0.20; pxa0=xa00.03; rxa0=xa0−0.20; pxa0=xa00.04). After adjusting for smoking and other confounders, VL ≥75xa0copies/ml correlated with a 11.2 (CI 95% [3.03–19.4], pxa0=xa0<0.01) decrease in DLCO. In Spearman’s Rank correlation, there was a negative correlation between change in VL and change in DLCO over time (ρxa0=xa0−0.47; pxa0=xa0<0.01).ConclusionThe presence of viremia in individuals with HIV is independently associated with impaired DLCO. Suppression of VL may allow for recovery in diffusing capacity over time, though the degree to which this occurs requires further investigation.