Asthma Maintenance
Total Page:16
File Type:pdf, Size:1020Kb
Asthma Maintenance Whitney Hanks, Pharm.D. Candidate 2012 Stephen Jamison, Pharm.D. Candidate 2012 Brett Parrish, Pharm.D. Candidate 2012 Bernie R. Olin, Pharm.D., Associate Clinical Professor and Director Drug Information Center Harrison School of Pharmacy Auburn University UNIVERSAL ACTIVITY NUMBER (UAN): 0178-0000-12-113-H04-P 1.5 Contact Hours | 0.15 CEUs expiration date: 12/12/2015 Alabama Pharmacy Association | 334.271.4222 | www.aparx.org | [email protected] Asthma Maintenance Pharmacist learning objectives: predisposition to the development of asthma, yet the • Describe how and why asthma affects patients understanding remains multi-part and incomplete. of different gender, ethnicity, and age. Genetic factors are thought to account for 35% to 70% • Explain the different environmental risk factors of the vulnerability. As a result, genetic predisposition that affect the development of asthma. to atopy (genetically determined state of hypersensitivity to environmental allergens) is a • Discuss spirometry and its role in diagnosing significant risk factor for developing asthma although asthma. not all atopic individuals develop asthma nor do all • Identify the two main goals of asthma therapy. asthmatics exhibit atopy.1,2 • Identify the most effective long term asthma Environmental risk factors for the control medications. development of asthma include socioeconomic status, • family size, exposure to secondhand tobacco smoke at Introduction infancy, allergen exposure, urbanization, and Asthma is an intricate disorder characterized decreased exposure to common childhood infectious by variable and recurring symptoms, airflow agents. The “hygiene hypothesis” proposes that obstruction, bronchial hyper-responsiveness, and genetically susceptible individuals develop allergies underlying inflammation. The interaction of these and asthma by allowing the allergic immunologic characteristics can determine the clinical symptoms, system (T-helper cell type 2 lymphocytes) to develop the severity of asthma, and the patient’s response to instead of the immunologic system used to fight treatment.1 An estimated 20.5 million persons in the infections (T-helper cell type 1 lymphocytes), and is United States have asthma, about 7% of the being used to explain the increase of asthma in population. In addition, asthma is the most common Western countries.2 The first 2 years of life appear to chronic disease among children in the United States, be most important for the exposures to produce an with approximately 6.5 million children affected. The alteration in the immune response system. Support for incidence rate is highest in children 5–17 years of the hygiene hypothesis for asthma comes from studies age.2,3 Over time the occurrence of asthma worldwide demonstrating a lower risk for asthma in children who steadily continues to increase. live on farms and are exposed to high levels of Asthma accounts for 1.6% of all ambulatory bacteria, in those with a large number of siblings, in care visits, results in more than 497,000 those with early enrollment into child care, in those hospitalizations and 1.8 million emergency with exposure to cats and dogs early in life, or in those department visits per year. Asthma is the third leading with exposure to fewer antibiotics. reason of preventable hospitalization in the United Risk factors for early (<3 years of age) States, and children younger than 15 years of age have recurrent wheezing associated with viral infections the highest rate of hospitalization at 31 per 10,000 include low birth weight, male gender, and parental population. In young children, aged 0 to 10 years of smoking. However, this early pattern is a result of age, the risk of asthma is greater in boys than in girls, smaller airways, and these risk factors are not the risk becomes about equal during puberty, and then necessarily risk factors for asthma in later life. Atopy is greater in women than in men.2,3 is the predominant risk factor for children to have Ethnic minorities continue to share the continued asthma.2 burden of asthma disproportionately. African Occupational asthma in previously healthy Americans have a higher prevalence than whites, but individuals depicts the effect of environment on the this appears to be a result of urbanization and not race development of asthma. Although, a variety of triggers or socioeconomic status. African Americans are three can have different degrees of importance from patient times as likely to be hospitalized and approximately to patient. Environmental exposures are the most 2.5 times more likely to die from asthma. In addition, important precipitants of severe asthma African Americans and Puerto Ricans living in inner exacerbations. Epidemics of severe asthma in cities cities are four times more likely to experience have followed exposures to high concentrations of emergency department visits than whites. These aeroallergens. Viral respiratory tract infections remain patterns are likely a result of poor access to health the single most significant precipitant of severe care.2 asthma in children, and are an important trigger in adults as well. Other possible factors include air Etiology pollution, sinusitis, food preservatives, and drugs.1 Asthma is a partially inherited, complex disease that requires a gene-by-environment Pathophysiology interaction for its development. Epidemiologic studies Asthma is a chronic inflammatory disorder of strongly support the concept of a genetic the airways in which many cells and cellular elements 1 Asthma Maintenance | Alabama Pharmacy Association | www.aparx.org play a role. The elements normally involved consist of normal breathing or prolonged phase of forced mast cells, eosinophils, neutrophils, T lymphocytes, exhalation, hyper- expansion of the thorax, use of macrophages, and epithelial cells. In susceptible accessory muscles, appearance of hunched shoulders, individuals, this inflammation causes recurrent or chest deformity. Finally, the skin is evaluated for episodes of coughing, wheezing, breathlessness, and atopic dermatitis and eczema.1 chest tightness. These episodes are usually associated Spirometry can demonstrate obstruction and with widespread but variable airflow obstruction that is often reversible either spontaneously or with Spirometry is an essential objective measure to treatment.1 establishassess reversibility the diagnosis in patients of asthma ≥5 becauseyears of theage. medical Airflow limitation is caused by a variety of history and physical examination are not reliable changes in the airway, but all changes are influenced means of excluding other diagnoses or of assessing by airway inflammation. Bronchoconstriction entails lung status. Spirometry is the most widely available bronchial smooth muscle contraction that quickly and useful pulmonary function test. It provides narrows the airways in response to exposure to a information about the obstructive aspect of asthma, variety of stimuli, including allergens or irritants. and allows for measurement of all lung volumes and Airway hyper-responsiveness is an exaggerated capacities except residual volume, functional residual bronchoconstrictor response to stimuli. Last, airway capacity, and total lung capacity. Spirometry is edema can develop as the disease becomes more generally recommended, rather than measurements persistent and inflammation becomes more by a peak flow meter, due to wide variability in peak progressive. Edema, mucus hypersecretion, and flow meters and reference values. Peak flow meters formation of mucus can further decrease and limit are an inexpensive way to measure a patient’s peak airflow. This can lead to remodeling of the airways. expiratory flow, also known as the maximum forced Reversibility of airflow limitation may be incomplete expiratory flow. This is the maximum flow obtained in some patients. Persistent changes in airway during the forced vital capacity. Peak flow meters are structure can occur including sub-basement fibrosis, more used for monitoring and not as diagnostic tools.2 mucus hypersecretion, injury to epithelial cells, smooth muscle hypertrophy, and formation of new Goals of therapy blood vessels.2 The main two goals of asthma therapy are to reduce a patient’s impairment and reduce the patient’s Diagnosis risk of worsening asthma. The objectives that make up To establish a diagnosis of asthma, the reducing impairment are to prevent chronic problems, clinician needs to determine that the patient’s reducing the need for SABAs for quick relief of symptoms are of recurrent episodes of airflow symptoms, maintain normal pulmonary function, obstruction or airway hyper-responsiveness. As well, maintain normal daily activity for patients, and to other diagnoses need to be excluded. Airflow meet the patients’ desires with satisfaction of care. obstruction is thought to be at least partially The main points of reducing risk for asthma reversible, measured by spirometry. Reversibility is progression are to avoid recurrent exacerbations of determined by an increase in forced expiratory asthma and minimize the need for emergency room volume (FEV1 visits or hospitalization, to prevent loss of lung measure after inhalation of a short-acting beta2- function, and to provide optimal drug therapy with agonist (SABA).) of Some >200 studies mL and indicate ≥12% from that anbaseline increase minimal or no adverse events.1 predicted FEV1 after inhalation of a SABA may have higher likelihood of separating ofpatients ≥10 percent who have of the asthma from those