Occupational upper airway disease
Section snippets
Structure and function of the upper airway
As inspired air travels through the upper airway, its temperature is adjusted to near body temperature, and its relative humidity is brought to between 75% and 80%. The vascular supply of the nose has a central role in regulating temperature and humidity for the respiratory tract. The nasal passages have a diurnal variation in patency that alternates between the two sides (the so-called “nasal cycle”) and results in cyclical changes in airflow from left and right nares. In most circumstances,
Pathophysiology
The upper airway may respond to environmental stimuli through allergic or neurogenic mechanisms. Inflammatory changes in the upper airway may lead to rhinitis, sinusitis, pharyngitis, or laryngitis. Rhinitis has been divided into allergic and nonallergic subcategories (Box 1). Individuals who are suspected of having allergic or nonallergic rhinitis report increased congestion after exposure to airborne irritants such as cigarette smoke, perfumes, cleaning agents, and temperature/humidity
Occupational irritant rhinitis
Chemical irritants in office environments include combustion products from tobacco smoke and malfunctioning appliances, and volatile organic compounds from cleaning products, office supplies and machines, building materials, and furnishings. Industrial settings present workers with an even wider range of airborne irritants. Extreme forms of industrial irritant rhinitis occur in electroplaters and others who are exposed to chromic acid, which may cause nasal mucosal ulcerations and even septal
Sinusitis
Relatively few studies examined sinusitis related to occupational exposures. Surveys of furriers, spice workers, vegetable picklers, hemp workers, and grain and flour workers revealed increased prevalence rates of self-reported sinusitis symptoms [25], [26]. Clinically, a worker who recounts a history of apparent occupational rhinitis followed by sinusitis that is refractory to antibiotic treatment should be reassessed from the standpoint of allergen or irritant avoidance.
Pathophysiology
Much more is known about the mechanisms of allergen-mediated laryngeal dysfunction than that following irritant exposure. Allergen-induced laryngeal edema is seen as part of the cascade of immune-regulated inflammatory events of Type I hypersensitivity reactions [7]. Following allergen exposure, sensitized individuals will develop typical mast cell and IgE-mediated, immune responses that lead to swelling of the laryngeal structures with consequent symptoms of upper airway obstruction, and
Summary
The upper airway plays a critical role in filtering and conditioning air for the lungs. It provides the first line of warning and defense against microbials, allergens, and toxic inhalants. Current evidence suggests that the upper airway is susceptible to many of the pathogenic processes that the agents cause in the lower respiratory tract. Work-related rhinosinusitis or vocal cord dysfunction should prompt physicians and employers to identify the injurious agent(s) and formulate strategies to
Acknowledgements
Thanks to Dr. Dennis Shusterman for review of this manuscript and to Ms Jen Shindoll for her assistance in preparation of the manuscript.
References (42)
- et al.
Physiologic responses to intranasal dose-response challenges with histamine, methacholine, bradykinin, and prostaglandin in adult volunteers with and without nasal allergy
J Allergy Clin Immunol
(1990) - et al.
How and why the nose runs
J Allergy Clin Immunol
(1991) Sensory, parasympathetic, and sympathetic neural influences in the nasal mucosa
J Allergy Clin Immunol
(1992)- et al.
Nasal congestion secondary to allergic rhinitis as a cause of sleep disturbance and daytime fatigue and the response to topical nasal corticosteroids
J Allergy Clin Immunol
(1998) - et al.
Nasal obstruction as a risk factor for sleep-disordered breathing. The University of Wisconsin Sleep and Respiratory Research Group
J Allergy Clin Immunol
(1997) - et al.
Subjects with seasonal allergic rhinitis and nonrhinitic subjects react differently to nasal provocation with chlorine gas
J Allergy Clin Immunol
(1998) - et al.
Reflex effects of chemical irritation of the upper airways on the laryngeal lumen in cats
Respir Physiol
(1973) - et al.
The irritable larynx syndrome
J Voice
(1999) - et al.
Extrathoracic and intrathoracic airway responsiveness in sinusitis
J Allergy Clin Immunol
(1995) - et al.
Clinical significance of pulmonary function tests: upper airway obstruction
Chest
(1981)