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Acute Exacerbations of Asthma

Sep 2, 2010 | By Gail Morris
Acute Exacerbations of Asthma
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Asthma is a disease whose physiological changes include inflammation of the airways caused by a variety of factors. The person experiences partial or completely reversible constriction of the smaller airways in the lungs. According to Dr. Gary Rachelefsky, in his article published August 2003 in Pediatrics, asthma exacerbations are the leading cause of hospital admission for children in the U.S. who are younger than 5. According to national guidelines, an exacerbation is defined as an increase in symptoms and a decrease in lung function. Most children and adults with asthma can sense even a small change in lung function that can be documented using spirometry or peak flow measurements.

Excess Mucus

There are two different biological changes that occur in the body when there is an asthma exacerbation or asthma attack. The first is an increased production and buildup of mucus in the airways, according to MayoClinic.com. The mucus reduces the amount of oxygen that can be exchanged at the level of the small airways. It can plug the smallest airways where oxygen is exchanged.

Inflammation

Inflammation and swelling of the airways is the second biological change that occurs, according to MayoClinic.com. These changes result in narrowed spaces, also reducing the amount of oxygen exchanged at the lung tissue. The inflammation and swelling can be minor to severe, and it varies from person to person. Inflammation, swelling and mucus can be triggered by an allergic reaction to a protein molecule, or from exercise.

Portable Spirometry

A measure of how much inflammation and mucus is present can be made with a portable spirometry measurement. In a study published in the Journal of Asthma in March 2009, researchers found that portable spirometry can be successfully used by children to determine the severity of the airway obstruction during an acute exacerbation of the disease. This non-invasive measurement gives patients and their families a unique and objective way of determining whether emergency care must be sought or if home treatments are successful.

Oxygen Saturation

Blood is circulated through the small airways of the lungs, where it exchanges oxygen for carbon dioxide. When those airways are narrowed and filled with mucus, oxygen exchange is limited and the blood doesn't get enough oxygen to support some vital functions. People who are experiencing an exacerbation of their asthma find themselves short of breath. According to the Agency for Healthcare Research and Quality, physicians test for oxygen saturation in the blood and subjectively measure cyanosis, or the blue coloring under the nail beds and lips that result from low oxygen supply.

Clinical Symptoms

These physiological changes result in observable clinical symptoms, according to the Merck Manuals Online Medical Library. Symptoms can include shortness of breath, coughing, wheezing, increase rate of breathing, increased heart rate, upright posture, breathing through pursed lips, inability to speak and a prolonged expiratory phase of breathing.

Danger Signs

Patients can suffer a severe exacerbation that results in respiratory failure and death. According to the Merck Manuals Online Medical Library, symptoms of impending respiratory failure can include a combination of altered consciousness as the brain is severely deprived of oxygen, blue-tinged nail beds and lips, hyper-inflated lungs and drooling as the work of breathing becomes so difficult that the patient is no longer able to handle swallowing her own saliva.

References

Article reviewed by Anton Alden Last updated on: Sep 2, 2010

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