From the Guidelines
The primary mechanism of death in asthma is asphyxia due to severe airway obstruction.
Key Factors Contributing to Asphyxia
- Bronchoconstriction: Contraction of bronchial smooth muscle narrows the airways, limiting airflow [ 1 ].
- Airway inflammation: Inflammation leads to edema, mucus hypersecretion, and formation of inspissated mucus plugs, further limiting airflow [ 1 ].
- Mucous plugging: Blocks airways, preventing air from reaching the lungs [ 1 ].
Complications Leading to Fatalities
- Tension pneumothorax: Air leaks into the space between the lung and chest wall, causing the lung to collapse [ 1 ].
- Lobar atelectasis: Collapse of an entire lobe of the lung, reducing lung function [ 1 ].
- Pneumonia: Infection of the lungs, which can be fatal in severe cases [ 1 ].
- Pulmonary edema: Fluid buildup in the lungs, making it difficult to breathe [ 1 ].
Pathophysiology of Asthma
- Airway hyperresponsiveness: Exaggerated response to stimuli, leading to bronchoconstriction [ 1 ].
- Airway remodeling: Permanent changes in airway structure, including sub-basement fibrosis, smooth muscle hypertrophy, and angiogenesis [ 1 ].
Clinical Implications
- Severe asthma exacerbations: Can lead to hypercarbia, acidemia, hypotension, and depressed mental status [ 1 ].
- Near-fatal asthma: Often associated with reduced perception of dyspnea, which can delay seeking medical attention [ 1 ].
From the Research
Mechanism of Death in Asthma
The mechanism of death in asthma is complex and multifactorial. Some of the key factors that contribute to asthma mortality include:
- Disease severity and poor disease management 2, 3
- Adverse psychosocial circumstances 2
- Bronchial hyperresponsiveness and airway obstruction 3
- Inflammation and eosinophil-rich inflammatory cell infiltrate 2, 4
- Mucoid plugging of the airway lumen 2
- Pneumothorax and surgical emphysema of the mediastinum 2
Pathophysiological Mechanisms
The pathophysiological mechanisms of asthma involve:
- Chronic bronchial hyperreactivity 4
- Epithelial damage and deposition of collagen beneath the basement membrane 4
- Eosinophilic and lymphocytic infiltration 4
- Hypertrophy and hyperplasia of goblet cells, submucosal glands, and airway smooth muscle 4
- Activation of CD4+ lymphocytes, the Th2 subtype, in the airways 4
Types of Fatal Asthma
There are two distinct types of fatal asthma:
- Type I: slow onset-late arrival, characterized by poor asthma control, increased use of bronchodilators, late arrival for care, and underutilization of glucocorticosteroids, with eosinophilia in the airways 5
- Type II: sudden, unexpected, and rapidly progressive attack, characterized by neutrophilia in the airways 5