Acute Respiratory Tract Reactions Induced by External Factors
Essentials
Sudden exposure to irritating chemicals may cause transitory symptoms of respiratory tract irritation, but in the most severe cases it may lead to pulmonary oedema and even death.
Immediately starting treatment with inhaled and systemic glucocorticoid aims at preventing the development of asthma and pulmonary oedema.
If strong exposure is suspected, the patient should be followed up in a hospital for a few days.
Further investigations at the pulmonary outpatient clinic are indicated.
It is important to refer exposed employees and other persons without delay to health care services in order to start inhaled glucocorticoid treatment.
Exposure
Fires
Mixtures of various gases and particulate substances
E.g., acrolein is released from burning oil products and plastics.
Industrial exposure
Gases released in industrial processes
Gas leaks in industrial plants and during transportation
Home environment
Severe exposure at home environment is rare. Check also locally relevant data.
Causes
Strong alkali (e.g. ammonia and caustic soda) and acids as well as strongly oxidizing agents (e.g. hydrogen peroxide and ozone) and inorganic chlorine and sulphur compounds are typical causes.
Any irritant gas can cause life-threatening alveolar injury if the exposure is very intensive or lasts long.
Manifestations
The symptoms caused by the exposure may be manifested in many different forms. Below they are ordered from the mildest to the most severe ones.
RUDS (reactive upper airway dysfunction syndrome)
Acute rhinitis
Acute maxillary sinusitis
Laryngitis or bronchitis with associated cough, pharyngeal irritation and a need to clear the throat
Obliterating bronchiolitis
The symptoms start acutely and then alleviate but worsen again after 1 to 3 weeks.
May subside within some months but may also remain chronic
Acute toxic pneumonitis
Dyspnoea that may only appear after 4 to 72 hours after the exposure
Often leads to a life-threatening condition that is similar to pulmonary oedema.
Investigations
Emergency investigations
Chest x-ray
Oxygen saturation or arterial blood sample
PEF measurement
CRP, basic blood count
Clinical status of the upper respiratory tract
Full blood and urine samples (to be frozen)
Further investigations
Performed as soon as the patient's condition allows:
spirometry and bronchodilator test
histamine or methacholine exposure
24 h follow-up of PEF.
Treatment
Acute treatment
First 5 days: the patient is given as soon as possible after the exposure (preferably within 15 minutes) 800-1 200 µg of budesonide or beclomethasone or 500 µg of fluticasone by inhalation using an inhalation chamber, or 2 ml of budesonide 0.5 mg/ml using a nebulizer. The dose is repeated at six-hour intervals.
After 5 days: the treatment is withdrawn unless there are pulmonary findings in which case the treatment will be continued until recovery.
If the patient is asymptomatic during follow-up and the initial respiratory function tests, including histamine or methacholine exposure, were normal, discontinuation of the pharmacological treatment may be considered.
Gradation of care
Minor exposure and mild symptoms are treated in outpatient care.
High-dose inhaled glucocorticoid for at least 5 days or until the lung function tests have been performed
Follow-up visit after 1 to 2 weeks including pulmonary function tests and, if considered necessary, consultation with a pulmonary specialist
Intensive exposure or severe symptoms
Inhaled glucocorticoid
Bronchodilator drugs, supplemental oxygen, systemic glucocorticoid as needed, transfer to specialist care
Further investigations and treatment in a pulmonary department
References
Lindström I, Lantto J, Karvala K, et al. Occupations and exposure events in acute and subacute irritant-induced asthma. Occup Environ Med 2021;78(11):793-800. [PubMed]