Persistent effects of chlorine inhalation on respiratory health

Abstract

Chlorine gas is a toxic respiratory irritant that is considered a chemical threat agent because of the potential for release in industrial accidents or terrorist attacks. Chlorine inhalation damages the respiratory tract, including the airways and distal lung, and can result in acute lung injury. Some individuals exposed to chlorine experience a full recovery from acute injury, whereas others develop persistent adverse effects, such as respiratory symptoms, inflammation, and lung-function decrements. In animal models, chlorine can produce persistent inflammation, remodeling, and obstruction in large or small airways, depending on species. Airways with pseudostratified epithelium are repaired efficiently, with surviving basal epithelial cells serving as progenitor cells that repopulate the complement of differentiated cell types. Distal airways lacking basal cells are repaired less efficiently, leading to chronic inflammation and fibrosis at these sites. Persistent chlorine-induced airway disease in humans is treated with asthma medication to relieve symptoms. However, such treatment does not ameliorate the underlying disease pathogenesis, so treatments that are more effective at preventing initial development of airway disease after irritant gas exposure and at reversing established disease are needed.

Awareness of Toxicity Induced by Chlorine

“…Also, multiple drug therapies, such as corticosteroids, adrenergic, and anticholinergic bronchodilators, that are approved for other lung diseases, are useful in chlorine toxicity. However, these treatments control symptoms, but, do not ameliorate the primary pathogenesis (12).…”

The influence of chlorine in indoor swimming pools on the composition of breathing phase of professional swimmers

“…This prolonged exposition lead to secondary acute airway obstruction and sometimes pulmonary edema, which may convert into chronic process. The cause of chronic symptoms may be chlorine induced pulmonary inflammation and remodeling [18] sometimes called as chlorine-induced reactive airways dysfunction syndrome (RADS) [19]. Persistent chlorine induced airway irritation may be responsible for development of asthma like symptoms, but with more persistent consequences [18,20].…”

“…The cause of chronic symptoms may be chlorine induced pulmonary inflammation and remodeling [18] sometimes called as chlorine-induced reactive airways dysfunction syndrome (RADS) [19]. Persistent chlorine induced airway irritation may be responsible for development of asthma like symptoms, but with more persistent consequences [18,20]. Even short, but intensive exposure may result in persistent respiratory symptoms, complains and impairment of pulmonary function [21].…”

“…In acute chlorine gas exposure it is currently speculated that a transient receptor potential (TRP) channels have an important role in respiratory disease [22]. It has to be underlined that although the effect of chlorine on lungs and airways is often described as persistent in most publications acute high exposures are described [18] whereas according to our best knowledge the scarce data about effect of low dose persistent exposition on human lungs and airways. Moreover, at his stage there are no prospectively confirmed specific treatment, therefore in acute intoxication treatment regimens are symptomatic [23], however, based on experimental studies the vanilloid-type TRP channels family TRPV4 may be considered as a candidate for management of acute lung injury caused by acute chlorine gas exposure [22], but this needs to be confirmed in humans.…”

Respiratory

“…For example, inhalation of chlorine is toxic to the lungs, where low doses can cause airway injury and high doses can cause both airway and alveolar injury [150]. These injuries can manifest as dyspnea, hypoxemia, pulmonary edema, and pneumonitis [150]. High doses of carbon dioxide, such as that released from dry ice, can also induce respiratory failure.…”