Publications

There is no gold standard for determining poisoning incidence. We wished to compare four measures of poisoning incidence: International Classification of Diseases 9th Revision (ICD-9) principal (N-code) and supplemental external cause of injury (E-code) designations, poison control center (PCC) reporting, and detection by the Drug Abuse Warning Network (DAWN). We studied a case series at two urban hospitals. We assigned ICD-9 N-code and E-code classifications, determining whether these matched with medical records. We ascertained PCC and DAWN system reporting. A total of 724 subjects met entry criteria; 533 were studied (74%). We matched poisoning N-codes for 278 patients (52%), E-code by cause in 306 patients (57%), and E-code by intent in 171 patients (32%). A total of 383 patients (72%) received any poisoning N-code or any E-code. We found that PCC and DAWN reporting occurred for 123 of all patients (23%) and 399 of 487 eligible patients (82%), respectively. In multiple logistic regression, factors of age, hospital admission, suicidal intent, principal poisoning or overdose type, and mixed drug overdose were statistically significant predictors of case match or report varying by surveillance measure. Our findings indicate that common surveillance measures of poisoning and drug overdose may systematically undercount morbidity.

Metal fume fever is a flulike illness caused by zinc oxide inhalation and accompanied by an impressive pulmonary cellular response. We hypothesized that the syndrome is mediated by cytokines released in the lung after exposure to zinc oxide fume. We carried out 26 experimental welding exposures in 23 volunteer subjects, performing postexposure bronchoalveolar lavage (BAL) 3 h (n = 6), 8 h (n = 11), or 22 h (n = 9) after exposure. We detected tumor necrosis factor (TNF), interleukin-6 (IL-6), and interleukin-8 (IL-8) varying in a time- and exposure-related manner. The concentration of TNF in the BAL fluid supernatant was significantly greater at 3 h than at 8 h or 22 h after exposure (p < 0.05), exhibiting a statistically significant exposure-response relationship to airborne zinc at each follow-up time period (p < 0.05). TNF concentrations were statistically correlated with those of IL-6 in BAL supernatant obtained at 22 h (r = 0.78, p = 0.01) and with concentrations of IL-8 in BAL 8 h after exposure (r = 0.85, p = 0.001). IL-6 displayed a significant exposure-response relationship to zinc (p < 0.05) at 22 h. IL-8 exhibited a significant exposure-response relationship to zinc (p < 0.05) at 8 h after exposure, a time at which IL-8 correlated with marked increases in BAL fluid polymorphonuclear leukocytes (PMN) (r = 0.7, p = 0.01). Although we also detected interleukin-1 (IL-1) in BAL samples, this cytokine did not demonstrate a statistically significant exposure response. TNF, IL-6, and IL-8 in BAL fluid supernatant concentrations increased in a time and exposure-dependent fashion after zinc oxide welding fume exposure. The time course of increased cytokines, their correlations with one another and with PMN in the BAL fluid, and the consistency of our findings with the known kinetics and actions of these cytokines support the hypothesis that a network of cytokines is involved in the pathogenesis of metal fume fever.

We conducted a review of the literature detailing the respiratory effects of chlorine, an extremely important but toxic halogen. Historically, the heaviest mass inhalational exposures to chlorine resulted from World War I gassing. Currently potential human exposure to chlorine inhalation occurs in a variety of settings in the workplace, as a result of inadvertent environmental releases, and even in the home due to household cleaning mishaps. Chlorine species are highly reactive; tissue injury results from exposure to chlorine, hydrochloric acid, hypochlorous acid, or chloramines. Acute, high level exposure to chlorine gas in occupational or environmental settings results in a variety of dose-related lung effects ranging from respiratory mucus membrane irritation to pulmonary edema. Pulmonary function testing can reveal either obstructive or restrictive deficits immediately following exposure, with resolution over time in the majority of cases. However, some of those exposed may demonstrate long-term persistent obstructive or restrictive pulmonary deficits or increased nonspecific airway reactivity after high level exposure to chlorine gas. Symptoms and signs following inhalation of mixtures of chlorine-containing cleaners in the home are similar to those after occupational exposures and environmental releases. Although generally less severe, these events may be extremely common. Controlled human exposure data suggest that some subjects may be more responsive to the effects of chlorine gas; epidemiologic data also indicate that certain subpopulations (e.g., smokers) may be at greater risk of adverse outcome after chlorine inhalation. Although these findings are intriguing, additional study is needed to better delineate the risk factors that predispose toward the development of long-term pulmonary sequelae following chlorine gas exposure.

STUDY OBJECTIVE

To estimate the incidence of respiratory symptoms and physiologic abnormalities after inhalation of common irritant chemicals.

DESIGN

Structured interview of 12 months of poison control center (PCC) inhalation cases. Follow-up measurement of pulmonary function and airway responsiveness in a subgroup with symptoms 12 to 24 h postexposure.

SETTING

A regional PCC and clinical pulmonary function laboratory.

PATIENTS

Consecutive sample of 547 inhalation cases. Interviews of 299 subjects. Lung function follow-up in 10 subjects.

MEASUREMENTS AND MAIN RESULTS

Immediate respiratory symptoms were reported by 262 (88 percent) subjects; 12 to 24 h postexposure symptoms were reported by 130 (44 percent). Cigarette smoking was significantly related to immediate onset of cough (relative risk [RR] = 1.3; 95 percent confidence interval [CI], 1.1 to 1.5); both smoking (RR = 1.6; 95 percent CI, 1.1 to 2.1) and prior asthma (RR = 1.3; 95 percent CI, 1.1 to 1.6) were associated with wheeze, exhibiting multiplicative combined risk (RR = 2.8; 95 percent CI, 1.9 to 4.3). Of 10 subjects studied, none had abnormal airflow or lung volumes 8 +/- 4 days postexposure; 8 demonstrated increased airway responsiveness to methacholine. By three months, only one subject's increased responsiveness reversed; in three others, symptoms resolved but increased responsiveness remained.

CONCLUSIONS

Respiratory symptoms following irritant exposure are associated with smoking and asthma and typically resolve quickly. Continuing symptoms are associated with persistent increased airway responsiveness without other pulmonary function abnormalities. This may reflect newly induced airway changes or, alternatively, could represent underlying increased responsiveness in subjects symptomatic after irritant exposure.

OBJECTIVE

To estimate the incidence of work disability among adults with asthma and to evaluate a clinically based illness severity score as a predictor of such disability.

DESIGN

Baseline and follow-up telephone interviews and medical record review.

SETTING

University-based outpatient pulmonary specialty practice.

PATIENTS

Fifty-six patients interviewed at baseline; 42 reinterviewed 2 years later.

MEASUREMENTS

Work disability ascertained by interview report and defined as change in job duties, reduction in pay, or change in job or employment status attributed to asthma. Severity of asthma score derived from medical records and based on respiratory symptom frequency, asthma history, and prescribed medications. Pulmonary function by routine testing. Logistic regression analysis of the 5-year incidence of work disability on severity score and forced expiratory volume in 1 s (FEV1).

RESULTS

The 5-year work disability cumulative incidence was 19 percent for change in duties, 17 percent for reduction in pay, 20 percent for change in job or work status, and 36 percent for any of these measures. The median asthma score was 10 (range, 2 to 26). The mean FEV1 as a percent predicted (FEV1 percent) was 88 +/- 25 percent. Score and FEV1 percent were statistically correlated (r = -0.6, p < 0.0001). Severity of asthma score statistically predicted each measure of work disability (p < 0.01). Addition of FEV1 percent added little additional explanatory power to the logistic regression model (maximum chi 2 = 1.3, p > 0.2).

CONCLUSIONS

Work disability is common among adults with asthma. A severity of asthma score based on clinical variables is statistically correlated with lung function but appears to be a stronger predictor of disability than airflow measured at one point in time.

Methyl ethyl ketone is a common solvent but data on overdose in humans are scarce. We report a case of co-ingestion of methyl ethyl ketone together with methanol associated with a hyperosmolar coma without anion gap metabolic acidosis. Blood levels of methyl ethyl ketone and its metabolite, 2-butanol, indicated that this solvent did contribute approximately 20 mosm/L to an observed osmolar gap of 99 mosm/L. At the levels detected, methyl ethyl ketone may have inhibited methanol metabolism, contributing to the low serum formate (1.3 mmol/L) and normal anion gap despite a blood methanol of 67 mmol/L.

Although drugs are frequently detected when studied in trauma series, the association between specific trauma types (such as gun shot wound) and drug use complicates interpretation of such reports. We carried out a case control study of trauma deaths with drug detection matched by cause with non-drug detection trauma fatality controls. We studied 117 case and control pairs identified from medical examiner's records. By multiple logistic regression analysis, younger adult age (OR 3.1; 95% CI 1.5 to 6.1) and black race (OR 2.3; 95% CI 1.1 to 5.0) were both strongly associated with drug detection. In contrast, neither gender, intent (homicide, suicide or unintentional), primary trauma site, nor ethanol detection were significantly associated with drug detection. Our findings suggest that case mix variables should be considered when interpreting the drug use rates in trauma.

We reviewed the relationship between occupational respiratory medicine and the environmental health aspects of air pollution control. Although these fields share epidemiologic and toxicologic concerns, they collaborate infrequently. From an historical perspective, both occupational health and air pollution control efforts increased in response to the Industrial Revolution but only occasionally overlapped. Moreover, they were undermined by the belief in "bad air" as the cause of epidemic disease. In the twentieth century, occupational medicine and industrial hygiene professionals together addressed mass air pollution exposure incidents, but this period of interdisciplinary activity was brief. Later regulatory approaches, together with economic pressures, have tended to divide rather than integrate occupational and environmental health. Despite their differences, these disciplines are linked by common scientific challenges. Recent governmental and non-governmental efforts suggests that future efforts in occupational health and air pollution control may become better coordinated.

Nurse practitioners with master's degrees were surveyed to assess the type and volume of occupational health services provided by primary care as compared with occupational health practitioners and the knowledge base in occupational health in these two groups. Thirty-six percent of 224 nonoccupational health nurse practitioners reported caseloads with 10% or more occupationally related chief complaints; 21% reported treating work-related injury or illness at least once per week. By contrast, a large percentage of nonoccupational health practitioners failed the knowledge-based exam. Large-scale prevention of occupational illness and injury warrants that primary care providers receive training in occupational health.

A retrospective review of cases consulted by the San Francisco Bay Area Regional Poison Control Center during a 2-year period was performed to determine the causes and consequences of seizures associated with poisoning and drug intoxication. Of 233 charts coded as involving seizures, 191 occurred in humans and were available for analysis. The leading causes of seizures reported to the Poison Control Center were cyclic antidepressants (55 cases, 29%); cocaine and other stimulants (55 cases, 29%); diphenhydramine and other antihistamines (14 cases, 7%); theophylline (10 cases, 5%); and isoniazid (10 cases, 5%). Stimulants and diphenhydramine were more likely than other drugs to produce brief, self-limited seizures. In contrast, poisoning by cyclic antidepressants, cardiodepressant antiarrhythmic agents, or theophylline was more likely to be associated with death. Seizures in elderly patients were more likely to result in complications and death. The frequency of seizure-related cases by substance type was also compared with the results of an earlier survey performed in 1981, and found a striking increase in the proportion of seizures caused by cocaine and (23% in 1988 to 1989 compared with 4% in 1981). Poison Control Center data can provide valuable information about the causes and consequences of drug-related medical complications, as well as highlight changing trends in drug-related injury.