occupational asthma

Occupational Asthma

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Causes and symptoms

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asthma

a condition marked by recurrent attacks of dyspnea, with airway inflammation and wheezing due to spasmodic constriction of the bronchi; it is also known as bronchial asthma. Attacks vary greatly from occasional periods of wheezing and slight dyspnea to severe attacks that almost cause suffocation. An acute attack that lasts for several days is called status asthmaticus; this is a medical emergency that can be fatal. adj., adj asthmat´ic. Causes. Asthma can be classified into three types according to causative factors. Allergic or atopic asthma (sometimes called extrinsic asthma) is due to an allergy to antigens; usually the offending allergens are suspended in the air in the form of pollen, dust, smoke, automobile exhaust, or animal dander. More than half of the cases of asthma in children and young adults are of this type. Intrinsic asthma is usually secondary to chronic or recurrent infections of the bronchi, sinuses, or tonsils and adenoids. There is evidence that this type develops from a hypersensitivity to the bacteria or, more commonly, viruses causing the infection. Attacks can be precipitated by infections, emotional factors, and exposure to nonspecific irritants. The third type of asthma, mixed, is due to a combination of extrinsic and intrinsic factors.
There is an inherited tendency toward the development of extrinsic asthma. It is related to a hypersensitivity reaction of the immune response. The patient often gives a family medical history that includes allergies of one kind or another and a personal history of allergic disorders. Secondary factors affecting the severity of an attack or triggering its onset include events that produce emotional stress, environmental changes in humidity and temperature, and exposure to noxious fumes or other airborne allergens.Symptoms. Typically, an attack of asthma is characterized by dyspnea and a wheezing type of respiration. The patient usually assumes a classic sitting position, leaning forward so as to use all the accessory muscles of respiration. The skin is usually pale and moist with perspiration, but in a severe attack there may be cyanosis of the lips and nailbeds. In the early stages of the attack coughing may be dry; but as the attack progresses the cough becomes more productive of a thick, tenacious, mucoid sputum.  An asthma attack with respiratory distress. From Frazier et al., 2000.Treatment. The treatment of extrinsic asthma begins with attempts to determine the allergens causing the attacks. The cooperation of the patient is needed to relate onset of attacks with specific environmental substances and emotional factors that trigger or intensify symptoms. The patient with nonallergic asthma should avoid infections, nonspecific irritants, such as cigarette smoke, and other factors that provoke attacks.
Drugs given for the treatment of asthma are primarily used for the relief of symptoms. There is no cure for asthma but the disease can be controlled with an individualized regimen of drug therapy coupled with rest, relaxation, and avoidance of causative factors. Bronchodilators such as epinephrine and aminophylline may be used to enlarge the bronchioles, thus relieving respiratory embarrassment. Other drugs that thin the secretions and help in their ejection (expectorants) may also be prescribed.
The patient with status asthmaticus is very seriously ill and must receive special attention and medication to avoid excessive strain on the heart and severe respiratory difficulties that can be fatal.Patient Care. Because asthma is a chronic condition with an irregular pattern of remissions and exacerbations, education of the patient is essential to successful treatment. The plan of care must be highly individualized to meet the needs of the patient and must be designed to encourage active participation in the prescribed program and in self care. Most patients welcome the opportunity to learn more about their disorder and ways in which they can exert some control over the environmental and emotional events that are likely to precipitate an attack.
Exercises that improve posture are helpful in maintaining good air exchange. Special deep breathing exercises can be taught to the patient so that elasticity and full expansion of lung and bronchial tissues are maintained. (See also lung and chronic obstructive pulmonary disease.) Some asthmatic patients have developed a protective breathing pattern that is shallow and ineffective because of a fear that deep breathing will bring on an attack of coughing and wheezing. They will need help in breaking this pattern and learning to breathe deeply and fully expand the bronchi and lungs.
The patient should be encouraged to drink large quantities of fluids unless otherwise contraindicated. The extra fluids are needed to replace those lost during respiratory distress. The increased intake of fluids also can help thin the bronchial secretions so that they are more easily removed by coughing and deep breathing.
The patient should be warned of the hazards of extremes in eating, exercise, and emotional events such as prolonged laughing or crying. The key words are modification and moderation to avoid overtaxing and overstimulating the body systems. Relaxation techniques can be very helpful, especially if the patient can find a method that effectively reduces tension.
Asthmatic patients fare better if they feel that they do have some control over their disease and are not necessarily helpless victims of a debilitating incurable illness. There is no cure for asthma but there are ways in which one can adjust to the illness and minimize its effects.

occupational asthma