Pathophysiological Mechanisms of Asthma and Acute Asthma Exacerbation
Asthma is a disease that causes airways to narrow and swell with excess mucus making breathing difficult. When the condition flares, a patient may cough, wheeze and experience shortness of breath. Asthma can be very serious, even life-threatening, in some patients. Asthma cannot be cured, but its symptoms can be controlled, but it often changes over time. Knowing the pathophysiology of asthma can help healthcare providers understand how to help patients control their asthma symptoms.
Asthma itself is not a disease, but a term that describes a condition that some people have. Bush (2019) writing in Frontiers of Pediatrics says, asthma “is an umbrella term that should be used to describe a constellation of clinical symptoms, namely wheeze, breathlessness, chest tightness and cough, and should be followed by the question ‘what sort of asthma is this?’ Dissecting out the individual asthmas is increasingly important as novel biologicals with different modes of action are increasingly being deployed” (Bush, 2019, p. 2). Bush goes on to say that the conventional view of the pathophysiology of asthma is that the airway inflammation that accompanies asthma “leads to airway hyper-responsiveness and, secondary to repeated episodes of inflammation, airway remodeling” (Bush, 2019, p. 2). However, Bush says that this view is incorrect because there is only a weak correlation between inflammation and bronchial hyper-responsiveness. One symptom may cause hyper-responsiveness but not inflammation, or the reverse may also be true. The result is that asthma is much more complicated than it has traditionally been thought to be. What may be more helpful is to think about what causes the asthma risks.
The causes of asthma are not known, but appear to be both environmental and genetic. Having a close blood relative with asthma is a risk factor. Other risk factors for adults include having an allergic condition, being overweight, being a smoker, exposure to secondhand smoke, exhaust fumes, or other pollution, and occupational triggers. Asthma can also be triggered by airborne substances, respiratory infections, physical activity, cold air, air pollutants and irritants, some medications, stress, sulfites and preservatives in foods and beverages, and GERD (Mayo Clinic, 2018). Risk factors, according to Bush (2019) are the concern when it comes to asthma.
The symptoms of asthma vary as does the frequency and the triggers. Some common symptoms according to the Mayo Clinic (2018) include shortness of breath, chest tightness or pain, trouble sleeping due to shortness of breath, coughing and wheezing, and coughing and wheezing that worsens from respiratory viruses (Mayo Clinic, 2018). These symptoms may flare when a person is exercising, working near chemical fumes, gas or dust or when airborne allergies are also present. For children, asthma may seem like a cold or flu that recurs frequently.
Asthma is exacerbated when the symptoms become more serious and more frequent, when breathing becomes more difficult, and when the asthma sufferers need their inhalers more often. Raimondi, Gonzalez, Zaltsman, and Menga (2014) of Pulmonary Medicine explain, “In acute asthma during moderate or severe bronchospasm, arterial blood gas levels generally show slight decrease in partial carbon dioxide pressure without significant abnormality of arterial oxygen saturation” (Raimondi, Gonzalez, Zaltsman, & Menga, 2014, p. 2). Complications that indicate that asthma is exacerbated include increased interference with sleep, work or recreational activities, more sick days from school or work, permanent narrowing of the bronchial tubes, increase in the number of emergency room visits or hospitalizations due to asthma and side effects of long-term use of asthma medication (Mayo Clinic, 2018). Age may also be a factor in asthma exacerbation.
How Age and Genetics Impact Pathophysiology
Asthma often shows up in young children. It may appear with a respiratory viral infection in pre-school children. Environmental allergens can also trigger asthma in young children. Most asthma attacks are caused by respiratory viral infections, but if the allergens are present and a child is exposed to them, this can be a strong prediction of an asthma attack (Bush, 2019, p. 7). One way to predict asthma attacks in children is to use the Seasonal Asthma Exacerbation Prediction Index (SAEPI). While asthma does often affect children, adults can develop it too.
Asthma attacks can be brought on by non-adherence to the treatment plan in adults who may have had asthma since childhood. Uncontrolled inflammation, even if asthma symptoms are controlled, is a major risk factor for asthma attacks. “There are some asthma patients who never have an attack, implying either genetic protection or susceptibility factors, which are poorly understood” (Bush, 2019, p. 7). Much more research needs to be done on asthma and its risk factors and causes.
Diagnose, Prescribe and Treat Patient with Asthma
A child who presents with wheezing, breathlessness, chest tightness and cough may have asthma. To determine if that is the correct diagnosis, a lung function test (spirometry) and an exhaled nitric oxide test should be done. Allergy tests may be done to see if it is asthma triggered by an allergen. To treat a pediatric asthma patient, a healthcare provider may take a wait and see approach if the symptoms are mild. However, the Mayo Clinic (2019) says if the symptoms interfere with the child’s life significantly there are many medications that can be prescribed including inhaled corticosteroids, leukotriene modifiers, combination inhalers, theophylline, or immunomodulatory agents. Omalizumab (Xolair) or other allergy medications may be given for allergy induced asthma (Mayo Clinic, 2019).
Adults can also present with symptoms of asthma that resemble an upper respiratory infection. Durham, Fowler, Smith and Sterrett (2017) of The Nurse Practitioner explain that asthma symptoms in adults often occur along with respiratory infections and symptoms are similar. However, the frequency and severity should be considered with adult patients asthma diagnosis (Durham, Fowler, Smith, & Sterrett, 2017, p. 18). To treat adult asthma short-term relievers include albuterol and levalbuterol or ipratropium for moderate to severe exacerbations. Long-term controllers include prednisone and ICS, and other corticosteroids (Durham, Fowler, Smith, & Sterrett, 2017, p. 21).
Conclusion
Asthma should not be considered a disease, but a condition brought on by a number of triggers. It has many risk factors, two of which are age and genetics: it is most often seen in children and genetics play a role in the condition, but environment is a factor also. Asthma can be controlled with treatment adherence and avoidance of triggers if possible. If an asthma patient does not follow the plan of treatment, the condition can exacerbate and lead to hospitalizations or death.
References
Bush, A. (2019). Pathophysiological Mechanisms of Asthma. Frontiers in Pediatrics, 7(68), 1-17. Retrieved from https://www.ncbi.nlm.nih.gov/p...
Durham, C. O., Fowler, T., Smith, W., & Sterrett, J. (2017). Adult Asthma: Diagnosis and Treatment. The Nurse Practitioner, 42(11), 16-24. Retrieved from https://journals.lww.com/tnpj/...
Mayo Clinic. (2018, September 13). Asthma. Retrieved from Mayo Clinic: https://www.mayoclinic.org/dis...
Mayo Clinic. (2019, March 20). Childhood Asthma. Retrieved from Mayo Clinic: https://www.mayoclinic.org/dis...
Raimondi, G., Gonzalez, S., Zaltsman, J., & Menga, G. (2014). Spirometry and arterial blood gases in acute severe asthma. Pulmonary Medicine, 5(4), 1-15. Retrieved from https://www.webmedcentral.com/...
