Impact of changes in regular use of marijuana and/or tobacco on chronic bronchitis

We sought to evaluate possible changes in the prevalence of chronic bronchitis in relation to continuing or changing smoking status for marijuana and/or tobacco. For this purpose we followed 299 participants in a longitudinal cohort study of the impact of heavy habitual use of marijuana alone or with tobacco on respiratory symptoms over a mean of 9.8 years during which subjects underwent repeated administration of a detailed drug use and respiratory questionnaire at intervals of ≥1 yr. Using logistic regression, we calculated odds ratios to assess the relationship between chronic bronchitic symptoms and smoking status for marijuana and tobacco at the first visit (current smoking versus never smoking) and at the last follow-up visit (continuing smoking versus, separately, never smoking and former smoking). We found that continuing smokers of either marijuana or tobacco had a significantly increased likelihood of having chronic bronchitis at follow-up compared to both never smokers and former smokers. On the other hand, former smokers of either substance were no more likely to have chronic respiratory symptoms at follow-up than never smokers. These findings demonstrate the benefit of marijuana smoking cessation in resolving pre-existing symptoms of chronic bronchitis.     

Impact of Changes in Regular Use of Marijuana and/or Tobacco On Chronic Bronchitis

Abstract

We sought to evaluate possible changes in the prevalence of chronic bronchitis in relation to continuing or changing smoking status for marijuana and/or tobacco. For this purpose we followed 299 participants in a longitudinal cohort study of the impact of heavy habitual use of marijuana alone or with tobacco on respiratory symptoms over a mean of 9.8 years during which subjects underwent repeated administration of a detailed drug use and respiratory questionnaire at intervals of ≥1 yr. Using logistic regression, we calculated odds ratios to assess the relationship between chronic bronchitic symptoms and smoking status for marijuana and tobacco at the first visit (current smoking versus never smoking) and at the last follow-up visit (continuing smoking versus, separately, never smoking and former smoking). We found that continuing smokers of either marijuana or tobacco had a significantly increased likelihood of having chronic bronchitis at follow-up compared to both never smokers and former smokers. On the other hand, former smokers of either substance were no more likely to have chronic respiratory symptoms at follow-up than never smokers. These findings demonstrate the benefit of marijuana smoking cessation in resolving pre-existing symptoms of chronic bronchitis.     

Passive smoking exposure: a risk factor for chronic bronchitis and asthma in adults?

OBJECTIVE: The effects of passive smoke exposure on respiratory health are still under debate. Therefore, we examined the risk of respiratory symptoms related to passive smoke exposure among German adults within the European Community Respiratory Health Survey. METHODS: The questionnaire data of the population-based sample (n = 1,890) were analyzed. Multiple logistic regression models were carried out for current asthma (asthma symptoms or medication), chronic bronchitis (cough with phlegm for > or = 3 months per year), and wheezing as dependent variables, and self-reported exposure to passive smoke at home and at the workplace as independent variables after adjusting for city, age, gender, active smoking, and socioeconomic status as well as occupational exposure to dusts and/or gases. RESULTS: The relative odds for chronic bronchitis were significantly higher in subjects reporting involuntary tobacco smoke exposure in the workplace (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.16 to 3.11). Likewise, the adjusted OR for asthma was slightly elevated (OR, 1.51; 95% CI, 0.99 to 2.32). The risk of chronic bronchitis (OR, 3.07; 95% CI, 1.56 to 6.06), asthma (OR, 2.06; 95% CI, 1.07 to 3.97), and wheezing (OR, 2.12; 95% CI, 1.25 to 3.58) increased significantly with a daily exposure of > 8 h. CONCLUSION: The control of passive smoke exposure in the workplace might reduce the risk of respiratory symptoms independently of exposure to other airborne contaminants.     

Effects of marijuana smoking on pulmonary function and respiratory complications: a systematic review

BACKGROUND: The relationship between marijuana smoking and pulmonary function or respiratory complications is poorly understood; therefore, we conducted a systematic review of the impact of marijuana smoking on pulmonary function and respiratory complications. METHODS: Studies that evaluated the effect of marijuana smoking on pulmonary function and respiratory complications were selected from the MEDLINE, PsychINFO, and EMBASE databases according to predefined criteria from January 1, 1966, to October 28, 2005. Two independent reviewers extracted data and evaluated study quality based on established criteria. Study results were critically appraised for clinical applicability and research methods. RESULTS: Thirty-four publications met selection criteria. Reports were classified as challenge studies if they examined the association between short-term marijuana use and airway response; other reports were classified as studies of long-term marijuana smoking and pulmonary function or respiratory complications. Eleven of 12 challenge studies found an association between short-term marijuana administration and bronchodilation (eg, increases of 0.15-0.25 L in forced expiratory volume in 1 second). No consistent association was found between long-term marijuana smoking and airflow obstruction measures. All 14 studies that assessed long-term marijuana smoking and respiratory complications noted an association with increased respiratory symptoms, including cough, phlegm, and wheeze (eg, odds ratio, 2.00; 95% confidence interval, 1.32-3.01, for the association between marijuana smoking and cough). Studies were variable in their overall quality (eg, controlling for confounders, including tobacco smoking). CONCLUSIONS: Short-term exposure to marijuana is associated with bronchodilation. Physiologic data were inconclusive regarding an association between long-term marijuana smoking and airflow obstruction measures. Long-term marijuana smoking is associated with increased respiratory symptoms suggestive of obstructive lung disease.     

Pot smokers puffing away lung health

BackgroundMarijuana is the second most commonly used inhalational agent after tobacco. It has been used for therapeutic benefits in cancer, epilepsy, inflammation and pain. Inhalation of marijuana causes reversible and irreversible lung injury.CaseWe present a 26-year-old female with cough, chest pain, epistaxis, hemoptysis, night sweats and breathlessness few hours after smoking marijuana. Physical exam was positive for tachycardia, tachypnea, and diminished coarse breath sounds. Further investigation revealed elevated white blood cell count, chest X-ray, computed tomography of the chest showed bilateral patchy infiltrates. The patient was managed with short term steroid, as antibiotics alone did not work. Radiological improvement of lung injury was noted within 36–48 h.ConclusionThere is a paucity of treatment guidelines for acute lung injury secondary to marijuana inhalation. We advocate early use of short-term steroids and also more awareness on quitting marijuana smoking to prevent life-threatening complications like myocardial infarction, diffuse alveolar hemorrhage and acute respiratory distress syndrome.     

Pulmonary status of habitual cocaine smokers.

We determined the prevalence of respiratory symptoms and lung dysfunction in a large sample of habitual smokers of freebase cocaine ("crack") alone and in combination with tobacco and/or marijuana. In addition, we compared these findings with those in an age- and race-matched sample of nonusers of crack who did or did not smoke tobacco and/or marijuana. A detailed respiratory and drug use questionnaire and a battery of lung function tests were administered to (1) a convenience sample of 202 habitual smokers of cocaine (cases) who denied intravenous drug abuse and (2) a reference sample of 99 nonusers of cocaine (control subjects). The cocaine smokers (85% black) included the following: 68 never-smokers of marijuana, of whom 43 currently smoked tobacco and 25 did not, and 134 ever-smokers of marijuana (42 current and 92 former), of whom 92 currently smoked tobacco and 42 did not. The control subjects (96% black) included the following: 69 never-smokers of marijuana, of whom 26 currently smoked tobacco and 43 did not, and 30 ever-smokers of marijuana (18 current and 12 former), of whom 21 currently smoked tobacco and 9 did not. Cases smoked an average of 6.5 g cocaine per week for a mean of 53 months. The median time of the most recent use of crack prior to study was 19 days (range less than 1 to 180 days). After controlling for the use of other smoked substances, frequent crack use was associated with: (1) a high prevalence of at least occasional occurrences of acute cardiorespiratory symptoms within 1 to 12 h after smoking cocaine (cough productive of black sputum [43.7%], hemoptysis [5.7%], chest pain [38.5%], usually worse with deep breathing, and cardiac palpitations [52.6%]) and (2) a mild but significant impairment in the diffusing capacity of the lung.(ABSTRACT TRUNCATED AT 250 WORDS)     

Medical symptoms associated with tobacco smoking with and without marijuana abuse among crack cocaine-dependent patients

Despite the widespread use of tobacco and marijuana by cocaine abusers, it remains unclear whether combined tobacco and marijuana smoking is more harmful than tobacco smoking alone in cocaine abusers. We investigated the differences in medical symptoms reported among 34 crack cocaine abusers who did not smoke tobacco or marijuana (C), 86 crack cocaine abusers who also smoked tobacco (C + T), and 48 crack abusers who smoked both tobacco and marijuana (C + T + M). Medical symptoms were recorded using a 134-item self-report instrument (MILCOM), and drug use was assessed using the Addiction Severity Index (ASI). After controlling for clinical and demographic differences, the C + T + M group reported significantly more total symptoms on the MILCOM as well as on the respiratory, digestive, general, and nose/throat subscales than the C + T or C groups. The C + T group reported higher total and respiratory and nose/throat symptoms than the C group. HOwever, the C group had the highest number of mood symptoms among the three groups. The C + T and C + T + M groups were comparable in number of cigarettes smoked and ASI scores. Although tobacco smoking is associated with higher reports of medical problems in crack abusers, smoking both marijuana and tobacco seems to be associated with greater medical problems than smoking tobacco alone. Tobacco smoking was not related to changes in cocaine use. Also, marijuana smoking does not appear to be associated with a reduction in tobacco or cocaine use.     

Clinical determinants of exacerbations in severe, early-onset COPD.

Chronic obstructive pulmonary disease (COPD) exacerbations impair health. The present authors analysed participants in the Boston Early-Onset COPD Study for familial aggregation and propensity for COPD exacerbations. In the present study, two exacerbation outcomes, episodes of cough and phlegm, and frequent exacerbations were analysed with multivariable modelling and generalised estimating equations. In early-onset COPD probands, passive tobacco smoke exposure within the home was strongly associated with episodes of cough and phlegm. Chronic phlegm production was associated with both exacerbation phenotypes in probands. In first-degree relatives of early-onset COPD probands, chronic bronchitis, episodic wheezing, pneumonia and active smoking were associated with the episodes of cough and phlegm phenotype. In relatives, identical characteristics plus exertional dyspnoea were associated with frequent exacerbations. Exacerbation risk increased with declining lung function. Familial aggregation for episodes of cough and phlegm was observed in relatives with severe obstruction. In conclusion, passive smoke exposure increases morbidity in severe early-onset chronic obstructive pulmonary disease probands, and chronic obstructive pulmonary disease exacerbations correlate with chronic sputum production in probands and relatives. The familial aggregation of exacerbations suggests a genetic basis for susceptibility to chronic obstructive pulmonary disease exacerbations.     

Airway obstruction in relation to symptoms in chronic respiratory disease--a nationally representative population study

We examined the severity of airway obstruction and the occurrence of respiratory symptoms in a large, nationally representative population sample and in a subgroup of subjects with chronic bronchitis and/or emphysema to obtain information for developing national prevention and treatment strategies for these diseases. The study population comprised of 7217 randomly selected subjects (aged 30 years and older) who participated in a comprehensive health examination survey. The 'cases' were subjects diagnosed as having chronic bronchitis and/or emphysema. The survey methods comprised of questionnaires, interviews, physical measurements, including spirometry, and clinical examinations. In the whole study population, the age-adjusted prevalence of chronic bronchitis and/or emphysema was 22% among men and 7% among women, whilst clinically relevant airways obstruction (FEV1/FVC%< or = 69) was present in 11% of men and in 5% of women.The occurrence of chronic cough and phlegm production was lowest among the 'cases' with pronounced obstruction (in 68% of men with severe and in 60% of women with moderate obstruction), whereas cold air-associated dyspnoea aggravation showed an inverse relationship, occurring most commonly in men (80%) with severe obstruction. Unexpectedly, half of the bronchitic women had never smoked. We conclude that the occurrence of certain bronchitic symptoms, such as chronic cough and phlegm production and cold air-associated dyspnoea aggravation, may to some degree indicate different stages of the disease. Smoking was not closely associated with airflow limitation in women here.     

Cannabis smoking and respiratory health: Consideration of the literature

The respiratory health effects from tobacco smoking are well described. Cannabis smoke contains a similar profile of carcinogenic chemicals as tobacco smoke but is inhaled more deeply. Although cannabis smoke is known to contain similar harmful and carcinogenic substances to tobacco smoke, relatively little is understood regarding the respiratory health effects from cannabis smoking. There is a need to integrate research on cannabis and respiratory health effects so that gaps in the literature can be identified and the more consistent findings can be consolidated with the purpose of educating smokers and health service providers. This review focuses on several aspects of respiratory health and cannabis use (as well as concurrent cannabis and tobacco use) and provides an update to (i) the pathophysiology; (ii) general respiratory health including symptoms of chronic bronchitis; and (iii) lung cancer.     

Bullous lung disease due to marijuana

Background and objective:   In contrast to the well-described effects of tobacco smoking upon pulmonary emphysema, with ∼15% of smokers being affected at the age of 65 years, the effects of marijuana smoking are rarely reported and poorly understood.
Methods:   We report a series of 10 patients (mean age 41 ± 9 years, eight male, two female), who presented over a period of 12 months to our respiratory unit with new respiratory symptoms, and who admitted to regular chronic marijuana smoking (>1 year continuously). Symptoms on presentation were dyspnoea ( n  = 4), pneumothorax ( n  = 4) and chest infection ( n  = 2).
Results:   High-resolution CT revealed asymmetrical, variably sized, emphysematous bullae in the upper and mid zones. However, the CXR was normal in four patients and lung function was normal in five.
Conclusions:   Marijuana smoking leads to asymmetrical bullous disease, often in the setting of normal CXR and lung function. In subjects who smoke marijuana, these pathological changes occur at a younger age (approximately 20 years earlier) than in tobacco smokers.     

Effectiveness of bupropion sustained release for smoking cessation in a health care setting: a randomized trial

BACKGROUND: The efficacy of bupropion hydrochloride sustained release (SR) (Zyban) for smoking cessation has been evaluated in clinical trials that included frequent in-person behavioral counseling, but not in actual practice settings. OBJECTIVE: To determine the differential effectiveness of 2 doses of bupropion SR in combination with behavioral interventions of minimal to moderate intensity in an actual practice setting. DESIGN: Open-label randomized trial, with 1 year of follow-up. SETTING: A large health system (Group Health Cooperative) based in Seattle. PARTICIPANTS: Adult smokers (N = 1524) interested in quitting smoking. INTERVENTIONS: Participants were randomly assigned to receive 1 of 4 combinations of bupropion SR (150 or 300 mg) and behavioral counseling (minimal or moderate intensity). MAIN OUTCOME MEASURES: The primary outcome measure was self-reported point-prevalence 7-day nonsmoking status at 3 and 12 months following the target quit date. Secondary outcomes included adverse and abstinence effects reported since beginning treatment with bupropion SR. RESULTS: At 3 months, a significantly higher rate of nonsmoking was observed among those receiving the larger bupropion SR dose (P=.005). At 12 months, moderate intensity counseling was associated significantly with a higher rate of nonsmoking (P=.001). At 3 months, the higher dose was associated with a significantly increased frequency of self-reported symptoms such as difficulty sleeping (P=.02), difficulty concentrating (P=.02), shakiness/tremor (P=.002), and gastrointestinal problems (P=.005)and a decreased frequency of reported desire to smoke (P=.001). CONCLUSIONS: In this actual practice setting, the combination of bupropion SR and minimal or moderate counseling was associated with 1-year quit rates of 23.6% to 33.2%. This suggests that existing health care systems can substantially decrease tobacco use rates among their enrollees if they provide these modest interventions.     

Asthma associated with the use of cocaine,heroin, and marijuana: A review of the evidence

Objective: A review of the evidence was conducted regarding asthma associated with the use of cocaine, heroin, and marijuana. Data Sources: A search of the English literature was performed via PubMed/Medline and EMBASE using the search terms asthma AND cocaine, heroin, and marijuana. When pertinent articles were found, salient references in those articles were assessed. Study Selection: Due to the relatively small number of studies, we included all studies and cases. Results: For several decades, case reports, retrospective studies, and laboratory investigations have demonstrated that inhalation of cocaine or heroin is associated with increased asthma symptoms and reduced pulmonary function. Smoking crack cocaine, nasal insufflation of cocaine or heroin, and smoking heroin increases the risk of emergency department visits and hospitalizations for asthma. Although frequent smoking of marijuana may cause symptoms of cough, sputum production, and wheezing in the general population, more studies are needed specifically in patients with asthma. Smoking marijuana with concomitant tobacco use is common and further worsens the respiratory symptoms. Conclusions: Use of cocaine and heroin in patients with asthma should be avoided. Pending further studies, it would be prudent for patients with asthma to avoid smoking marijuana. Clinicians need to be vigilant regarding use of these drugs in their patients with hyperreactive airway disease.     

Asthma, current wheezing, and tobacco use among adolescents and young adults in Costa Rica.

OBJECTIVES: To examine the prevalence of asthma and the relation between tobacco use and asthma among university students in Costa Rica. METHODS: Cross-sectional study of 1279 adolescents and young adults enrolled in careers in the health sciences in public and private universities in Costa Rica. RESULTS: Of the 1279 study participants, 105 (8.2%) had current asthma, and 136 (10.6%) reported wheezing in the previous 12 months (current wheezing). Among individuals with either current wheezing or current asthma, none was using anti-inflammatory medications for asthma (e.g., inhaled corticosteroids). Approximately one third of the study participants reported any cigarette smoking. Young adults who had current wheezing were 5.8 times more likely to smoke at least 10 cigarettes per day than those who had no current wheezing [95% confidence interval (CI) for odds ratio (OR) = 3.3-10.2, p < 0.001]. Similar results were observed when an alternative definition of asthma (current asthma) was used in the analysis (OR for smoking at least 10 cigarettes per day = 4.4, 95% CI = 2.3-8.5, p < 0.001). CONCLUSIONS: Adequate public health measures are needed to prevent tobacco use in Costa Rican adolescents and to promote smoking cessation among young adults. Young adults with asthma living in Latin American countries with high asthma prevalence, such as Costa Rica, should be better educated with regard to asthma and the risks of tobacco use.     

Prevalence of respiratory symptoms in an athlete population

This study aimed to look at the prevalence and type of respiratory symptoms experienced by athletes and to assess the possible influence on the perception of symptoms of training duration and environment. A group of 698 athletes (107 with diagnosed or self-reported asthma) filled out a questionnaire on their respiratory condition. They exercised either in cold air (n = 176), dry air (n = 384), humid air (n = 95) or mixed dry and humid air (n = 43). Past exercise-related symptoms reported by athletes were breathlessness (48.7%), phlegm production (22.8%), wheezing (15.6%), cough (15.2%), and chest tightness (7.4%). Only 25% of asthmatic athletes reported having current exercise-induced symptoms of breathlessness, 21.7%, wheezing and 17.4%, chest tightness; current exercise-induced symptoms of breathlessness, wheezing or chest tightness were also reported, respectively, in 38.9%, 3.6% and 2.7% of athletes without a diagnosis of asthma. The perception of exercise-induced symptoms was not influenced by the duration of training or environment. In conclusion, (1) a minority of asthmatic athletes report troublesome respiratory symptoms with exercise, (2) breathlessness is not more frequently reported in asthmatic athletes than in those without such diagnosis while cough and wheezing are more common in asthmatic subjects and (3) the prevalence of respiratory symptoms is independent of training environment and duration of training.     

Characteristics of Smoked Drug Use Among Cocaine Smokers

The authors collected data by structured interview from a convenience sample of 228 physically healthy, largely (82%) treatment-seeking, cocaine smokers with minimal histories of other smoked (other than tobacco and marijuana) or injection drug use. The vast majority of subjects also smoked either marijuana only (17.5%), tobacco only (17%), or both (61%), with onset of such smoking almost always (97%) preceding the initiation of regular cocaine smoking. There were few significant differences in sociodemographic or cocaine use characteristics among the subgroups of subjects smoking either cocaine only or cocaine and marijuana and/or tobacco. More than one-third of marijuana smokers quit (45%) or decreased (38%) their use after starting regular cocaine smoking, whereas only 5% of tobacco smokers did so. These findings suggest that marijuana smoking is more influenced by regular cocaine smoking than is tobacco smoking.     

The association between marijuana smoking and lung cancer: a systematic review

BACKGROUND: The association between marijuana smoking and lung cancer is unclear, and a systematic appraisal of this relationship has yet to be performed. Our objective was to assess the impact of marijuana smoking on the development of premalignant lung changes and lung cancer. METHODS: Studies assessing the impact of marijuana smoking on lung premalignant findings and lung cancer were selected from MEDLINE, PSYCHLIT, and EMBASE databases according to the following predefined criteria: English-language studies of persons 18 years or older identified from 1966 to the second week of October 2005 were included if they were research studies (ie, not letters, reviews, editorials, or limited case studies), involved persons who smoked marijuana, and examined premalignant or cancerous changes in the lung. RESULTS: Nineteen studies met selection criteria. Studies that examined lung cancer risk factors or premalignant changes in the lung found an association of marijuana smoking with increased tar exposure, alveolar macrophage tumoricidal dysfunction, increased oxidative stress, and bronchial mucosal histopathologic abnormalities compared with tobacco smokers or nonsmoking controls. Observational studies of subjects with marijuana exposure failed to demonstrate significant associations between marijuana smoking and lung cancer after adjusting for tobacco use. The primary methodologic deficiencies noted include selection bias, small sample size, limited generalizability, overall young participant age precluding sufficient lag time for lung cancer outcome identification, and lack of adjustment for tobacco smoking. CONCLUSION: Given the prevalence of marijuana smoking and studies predominantly supporting biological plausibility of an association of marijuana smoking with lung cancer on the basis of molecular, cellular, and histopathologic findings, physicians should advise patients regarding potential adverse health outcomes until further rigorous studies are performed that permit definitive conclusions.     

Patterns of smoking in Delhi and comparison of chronic respiratory morbidity among beedi and cigarette smokers

Tobacco smoking is common in developing countries including India with beedi and cigarette smoking being the main types. A community-based study carried out to study the chronic respiratory morbidity in the urban areas of Delhi was analyzed to determine the patterns of tobacco smoking and to compare the chronic respiratory morbidity among beedi and cigarette smokers. A random, stratified sample was selected from among the permanent residents, aged above 18 years, from nine clusters in Delhi. A standardized respiratory symptoms questionnaire was administered and clinical examination carried out followed by spirometry. The questionnaire included a detailed smoking history including type of smoking, number of cigarettes smoked per day and number of years the person had smoking. Chronic respiratory morbidity in beedi and cigarette smokers was measured in terms of prevalence of chronic respiratory symptoms (chronic cough, phlegm, breathlessness and wheezing) and by lung function results. It was observed that nearly 40% of adult males were current smokers. Beedi smoking was overall the commonest type of smoking in the community. Cigarette smoking was more common in the higher income groups and among the graduates and postgraduates. Beedi smoking was the main form of smoking among the lower and middle-income groups and among the illiterates and the less educated people. Very few female subjects admitted to smoking. The prevalence of symptomatics (those having one or more of chronic chest symptoms) was significantly higher in beedi smokers as compared to cigarette smokers in those smoking greater than 2.5 pack years. Prevalence of wheezing was however not significantly different. Multiple logistic regression analysis revealed type of smoking to be a significant independent determinant of occurrence of respiratory symptoms with the odds for occurrence of symptoms being 1.67 times greater in beedi smokers as compared to cigarette smokers. Lung function (FEV1/FVC and FEV1% predicted) showed significantly greater airways obstruction in beedi smokers as compared to cigarette smokers. It was concluded that the beedi smoking was as or more likely to cause clinical and functional impairment of lungs compared to cigarette smoking.     

Is clinical recognition of respiratory syncytial virus infection in hospitalized elderly and high-risk adults possible?

BACKGROUND: The clinical and radiographic features of respiratory syncytial virus (RSV) infection in elderly hospitalized persons have not been described in detail, to our knowledge, despite its relative frequent occurrence. METHODS: Clinical characteristics of 132 RSV infections were compared with 144 influenza A virus infections and with all non-RSV infections in elderly and high-risk persons admitted to the hospital with acute respiratory illness. Radiographic findings were categorized for RSV-infected persons. RESULTS: RSV was more commonly associated with nasal congestion (68% vs. 55%; P=.03), wheezing by history (73% vs. 53%; P=.002) and on examination (82% vs. 68%; P=.02), and lower temperature (P=.004) than influenza A virus. Compared with all non-RSV-infected subjects, nasal congestion (odds ratio [OR], 2.0 [95% confidence interval {CI}, 1.3-2.9]), wheezing on examination (OR, 1.8 [95% CI, 1.2-2.8]), and temperature >37.9 degrees C (OR, 1.6 [95% CI, 1.1-2.4]) were independent predictors of RSV infection, although their sensitivity and specificity were poor. New radiographic infiltrates were seen in approximately half of RSV-infected persons, and pneumonic opacities were typically small and unilateral. CONCLUSIONS: Although RSV causes a different clinical syndrome than influenza A virus, it is not readily differentiated on clinical grounds from influenza A nor from all non-RSV illnesses in elderly patients.     

Respiratory effects of cocaine "freebasing" among habitual users of marijuana with or without tobacco

Use of cocaine by smoking its alkaline precursor ("freebasing") has become increasingly prevalent. Recent studies of small numbers of cocaine users suggest that freebasing frequently causes cough, dyspnea, and abnormalities in diffusing capacity (DCO), although these findings could have been due to concomitant use of other drugs. We therefore evaluated the relationship between cocaine use by freebasing and chronic respiratory symptoms and lung dysfunction in a large sample of habitual smokers of marijuana with or without tobacco who denied intravenous drug abuse. The findings suggested that, among habitual marijuana smokers, "moderate" cocaine smoking damaged both large and small airways, as reflected by functional changes that were independent of concomitant marijuana use and appeared to be synergistic with the effects of tobacco. On the other hand, no adverse influence of cocaine smoking on the pulmonary microcirculation was demonstrated in our sample of freebase users.