Asthma Pathology Profile
How it works
The symptoms of asthma include chest pain, tightness of the chest, shortness of breath, coughing, and wheezing. These symptoms are caused by the constriction of the airways and excess mucus production. Asthma symptoms vary in each person; some may experience symptoms only while exercising, while others experience symptoms every day (Mayo Clinic Staff). Therefore, in some people asthma is a major problem that seriously impacts their life, while in others it is just a minor problem. A physician will commonly diagnose a patient with asthma by doing a spirometry test or a peak flow test and asking about the patient’s symptoms.
A spirometry test measures how much air a patient can exhale and how fast he or she breathes it out. The physician will calculate a predicted value for test scores based on age, gender, height, and other factors. If the patient’s test result is 80% or more of the predicted value it is “normal” and if results are below that, it indicates lung disease or that damage has occurred to the patient’s lungs. A peak flow test measures how fast a patient can breathe out. If this number is low, it indicates that the patient’s lungs are not functioning normally (Mayo Clinic Staff).
Physiological basis of the Pathology
In the lungs, inhaled allergens get checked by immune cells when antigen presenting cells present allergens to immune cells. In people without asthma, immune cells check the allergen and then disregard it in many cases. In people with asthma, the immune system has a reaction to this allergen. The immune cells of the lungs create inflammation in response and that makes the airways narrower and more difficult to breathe through: this is an asthma attack (“Pathophysiology of Asthma). Eosinophils are abundant in the tissues of the lungs and release their granules when they are presented with an environmental trigger. These granules contain things like histamine and platelet activating factor which cause inflammation. The release of granules also causes the smooth muscle around the bronchioles to spasm and secrete mucus which narrows the airways even more. Substances that trigger these attacks can be air pollution, smoke, dust, mold, and pet dander (Morris). Patients with asthma have inflamed airways that are hypersensitive to allergens or triggers. Patients without asthma do not have hypersensitive airways, which is why they can inhale these allergens and have no reaction to it.
It is thought that children exposed to bacteria early in life will have less risk of developing hypersensitive airways. This is because early exposure to a lot of bacteria keeps the immune cells in regulation and keeps them from becoming hyperactive. The exposure to bacteria also prevents immune cells from becoming dominate in allergic responses. The humoral immune system is in the lungs and protects them from inhaled pathogens. It is what contributes to reoccurring asthma attacks. The humoral immune system defends the body against inhaled pathogens by creating antibodies to fight against them. Once an inhaled pathogen causes an immune response, it will continue to cause successive immune responses. The humoral immune system antibodies remember these pathogens and attack them when they are inhaled again. These inhaled pathogens become triggers for the patient, meaning they will cause an asthma attack when the patient inhales them, making it important that the patient avoids their known triggers (“Pathophysiology of Asthma).
Risk Factors of the Pathology
Risk factors for asthma can be a genetic predisposition or from environmental factors. If a patient has a family history of asthma, it increases his or her chances of developing asthma. This is an intrinsic factor that is out of the patient’s control. Environmental factors are extrinsic and can be somewhat controlled by the patient avoiding triggers. Patients that are not exposed to bacteria, and viruses early in life have an increased susceptibility to develop asthma. This reduced exposure varies the proportion of immune cells so they are more reactive in protective responses. Early onset asthma is usually a result of genetic factors, while later onset asthma is due to environmental factors (Morris). Both of these factors increase the hypersensitivity of the airways, making asthma attacks more common.
Treatment for asthma is preventative along with medication that is taken long term. Preventatively, patients must monitor their breathing and avoid triggers that may lead to an asthma attack. Patients can monitor their breathing daily at home using handheld meters that measure their airflow, such as a peak flow meter. Along with preventative care, long-term medications are taken to control a patient’s asthma, and quick relief inhalers are taken during an asthma attack. Long-term medications are usually inhaled corticosteroids which decrease the chance of having an asthma attack. They control asthma symptoms by decreasing the reactivity of the airways, so when a pathogen is inhaled, the steroid reduces the inflammation and mucus production. Since these symptoms are reduced, the patient can breathe while they inhale the pathogen that might normally have caused an asthma attack. Corticosteroids are considered a long-term drug for asthma patients because it takes a while for them to work. Therefore, they are preventative to help reduce asthma attacks, but if a patient has an asthma attack, he or she will take a quick relief inhaler (“Asthma TreatmentDrugs). Quick relief inhalers are usually albuterol or Xopenex, which relieve symptoms quickly when inhaled. They are bronchodilators which allow the patient to breathe better (Mayo Clinic Staff). These bronchodilators widen the patients’ airways which allows them to breathe easier and relieves the constriction caused by their attack. There is no cure for asthma, but medication and preventative measures can usually can control asthma.
The prognosis of a patient with asthma is good if the patient treats their asthma. Even with treated asthma, a patient may miss work or school occasionally due to an attack. When children receive treatment for their asthma, it usually improves by late adolescence. Long-term with no treatment, patients can develop changes to their airways which could lead to chronic symptoms and more difficulty controlling the disease with treatment options. Over time, the airway begins to scar, and the membrane begins to thicken, which is irreversible. Patients who do not receive treatment are at a greater risk of mortality than those who receive treatment and control their asthma, although the mortality rate of asthma is low (Morris).
Significance of the Pathology
Asthma affects 16.4 million adults and seven million children in the United States, which is approximately ten percent of the population. In the United States, the mortality rate of asthma is higher in African Americans than in Caucasians. This difference in mortality is not only due to genetics but also due to affordability of treatment. It is suspected that minorities have a higher mortality rate because they struggle more to afford treatment (Morris). Preadolescence asthma occurs more often in boys than girls. In both cases, boys and girls are likely to experience a decrease or even disappearance of symptoms by age eighteen. Therefore, most patients with asthma are diagnosed at a young age. Asthma is more commonly diagnosed in industrialized nations where there is air pollution, smoking, and environmental allergens.