Asthma: Diagnosis and Management ____________________________________________________________
Coughing When secretions become too thick for cilia to handle, the sys- tem responds by coughing to remove the unwanted substance. Dry coughs in patients with asthma are generally the product of extra-thick mucus plugs or bronchioles so blocked that the mucus cannot be removed or moved through. Nasal and sinus drainage, a common symptom of allergies, may also irritate airways and produce a nagging, unproductive cough [13]. If a patient has been mouth breathing, the airways may become dry and have decreased elasticity, making it more difficult to clear them. If this is the case, the patient should be encouraged to take frequent sips of water or isotonic fluids (e.g., electrolyte replacement drinks). Wheezing Wheezing is considered to be a trademark of asthma, but it is not a definite indicator. The wheezing sound associated with asthma results from a forceful rush of air pushing through narrowed, constricted airway lumens. The surge of air causes vibrations that make the wheezing sound. In some cases, air- ways can be so constricted that the air flowing past a blockage is not sufficient to produce a wheeze. In very severe attacks, the absence of wheezing is a worrisome sign. It is important to note that patients with severe asthma have acute airway inflammation during an episode, and as stated previously, patients with chronic asthma have continuous symptoms of airway inflammation, which can eventually destroy airway tissue and alter lung function. Prolonged inflammation may result in permanent obstruction as a result of alteration of the bronchial walls. Unfortunately, after this change occurs, the airways may not respond to common treatment as quickly or at all. This is why it is important to use medication to reduce airway inflammation, subsequently preventing permanent obstruction [13]. Fatigue Breathing with asthma can fatigue the body. As exhalation is blocked and air is trapped in the lungs, more force is required to maintain adequate oxygen supply. To aid in exhalation, accessory muscles become involved, which can deplete the body of energy. Untreated asthma can produce severe degrees of fatigue for the patient, and this can become a critical situation warranting immediate intervention [13]. Lethargy, decreased response time, and weakness are all late signs of fatigue.
effortless flow of air during inhalation and exhalation. In the lung of a person with asthma, it is thought that the balance may be tipped toward the PNS and that this imbalance may result in narrowed bronchial tubes and asthma symptoms. There was once a belief that the PNS was solely responsible for airway sensitivity; however, studies now seem to indicate that, although the PNS is involved, it is not the major reason for inflammation in asthma[12; 13]. Researchers continue to study the importance of these neurotransmitters relative to bronchial muscle tone. Additionally, there is a proposed theory that some people with asthma have abnormal beta receptors and the proper neurotransmitters are blocked from reaching the appropriate receptors. When the nervous system becomes unbalanced due to this blockage, the parasympathetic nerves overreact and constrict the bronchial tubes. For some researchers, the “beta blockage theory” offers a better explanation of the cause(s) of asthma symptoms present in some patients after exposure to what are known as nonspecific triggers, such as viruses and extreme weather changes [12; 13]. However, it is still not under- stood how and when beta receptors would become defective. ELEMENTS OF AN ASTHMA ATTACK There are essentially five key elements of an asthma attack: muscle spasm, excess mucus, coughing, wheezing, and fatigue. While not all five elements are present for all patients, they are the most common physical manifestations of an episodic attack of the condition and should be evaluated and treated urgently. Muscle Spasm In response to irritation and immune response, muscles on the outer layer of the bronchi contract, causing a bronchospasm. Tightened muscles restrict the movement of air. Depending on the degree of airway narrowing, which differs for each patient and with the severity of the attack, the characteristic breathing difficulty, chest tightness, wheezing, and coughing will follow [13]. Excess Mucus Inflammation can produce excess mucus as a protective mechanism. During an asthma attack, glands secrete exces- sive amounts of thick mucus to compensate for the increased amount of irritants or allergens. The excess mucus clumps together in the airways, further narrowing the bronchial tubes by partially blocking the passageway and hindering breathing. This increased amount of mucus can also form plugs that clog very small airways. During an asthma episode, some patients attempt to clear their airways by coughing up what seems to be a mucus plug. However, patients may produce many plugs; consequently, they may have a continuous, irritating hacking cough. If left untreated, mucus plugs can prolong asthma episodes and increase the risk of infection [13].
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