Characterization of airway plugging in fatal asthma

doi:10.1016/S0002-9343(03)00241-9

The American Journal of Medicine

Volume 115, Issue 1, July 2003, Pages 6-11

https://doi.org/10.1016/S0002-9343(03)00241-9 Get rights and content

Abstract

Purpose

Case reports suggest that deaths due to asthma can occur without airway plugging. In this study, we examined the hypothesis that obstruction of the airway lumen by an exudate containing mucus and cells is a key feature of fatal asthma attacks.

Methods

We quantified airway narrowing and lumenal content in 275 airways from 93 patients with fatal asthma aged 10 to 49 years (59 white subjects and 34 Polynesian subjects, including 19 children), compared with airways from control patients who died suddenly without pulmonary diseases.

Results

The severity of lumenal occlusion ranged from 4% to 100% in these cases, but only five airways showed less than 20% occlusion. Compared with controls, patients with asthma had more lumenal occlusion (mean [± SD] open lumen, 42% ± 23% vs. 93% ± 8%), greater mucus occlusion (28% ± 13% vs. 5% ± 6%), and more occlusion by cells (30% ± 17% vs. 3% ± 2%, all P<0.0001). Airway narrowing was greater in larger airways (P<0.0001) and older patients (P = 0.009). Greater lumen content was associated with a higher proportion of cells (P = 0.003), and cells made up a higher proportion of the exudate in the small airways (P<0.0001). Lumenal mucus was greater in younger patients with asthma (P = 0.0007) and in Polynesian patients with asthma (P = 0.04).

Conclusion

Airway lumenal obstruction by an exudate composed of mucus and cells is a major contributing cause of fatal asthma in most patients.

Section snippets

Subjects

The airways of 93 patients who died in the community during an asthmatic episode were studied. They were selected from 178 cases of fatal asthma in white and Polynesian patients aged 10 to <50 years whose lung tissue was collected between 1975 and 1990 at the coroner’s morgue at the University of Auckland Medical School, Auckland, New Zealand, after excluding patients in whom other factors, such as anaphylaxis and pneumonia, may have contributed to death. Information about many of these

Results

There were similar numbers of men and women in the sample of patients with fatal asthma; most were young or middle-aged adults (Table 1). The mean (± SD) number of airways examined per case was 2.9 ± 1.8 (range, one to nine). There was no difference in the distribution of airway sizes in the two main ethnic groups.

The mean values for lumenal content of cells and mucus for the 275 airways from patients with asthma and the 28 control airways are shown in Table 2. The asthmatic airways had less

Discussion

Our results indicate that “dry airways” without lumenal occlusion are a rare feature of asthma death in adults and children of white and Polynesian ancestry. Compared with controls, patients with fatal asthma had more cells and mucus in airway lumens, even though it is likely that we underestimated the amount of lumenal contents because of plug shrinkage during tissue processing. We observed age-related increases in airway narrowing, as in a previous report (6). However, the greater mucus

Acknowledgements

We thank Tracey Weir and Danyi Zhou for technical assistance. This study could not have been performed without the help of Drs. T. Koelmeyer, P. Black, and J. Garrett of the University of Auckland School of Medicine.

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^☆: Supported by the British Columbia Lung Association, a Canadian Institute of Respiratory and Circulatory Health Research grant (#42537), and a National Institutes of Health grant (#HL64068).

View full text

Clinical studyCharacterization of airway plugging in fatal asthma☆

Abstract

Purpose

Methods

Results

Conclusion

Section snippets

Subjects

Results

Discussion

Acknowledgements

J Allergy Clin Immunol

Chest

Chest

Lancet

J Allergy Clin Immunol

Chest

The pathology of asthma

APMIS

Sudden-onset fatal asthma. A distinct entity with few eosinophils and relatively more neutrophils in the airway submucosa?

Am Rev Respir Dis

The effect of age and duration of disease on airway structure in fatal asthma

Am J Respir Crit Care Med

Reasons for racial differences in A & E attendance rates for asthma

N Z Med J

Death from asthma in Aucklandcircumstances and validation of causes

N Z Med J

Asthma mortality in New Zealanda two year national study

N Z Med J

A case-control study of deaths from asthma

Thorax

Lessons from the national asthma mortality studycircumstances surrounding death

N Z Med J

Clinical study
Characterization of airway plugging in fatal asthma☆