Asthma in Older Adults Workup

Updated: Oct 28, 2015
  • Author: Praveen Buddiga, MD; Chief Editor: Michael A Kaliner, MD  more...
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Workup

Approach Considerations

This usually involves procuring a clinical history of persistent cough or nocturnal cough, wheezing, shortness of breath, or chest tightness triggered by either allergic or nonallergic stimuli. Diagnostic testing may be conducted.

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Lab Studies

Spirometry measures the maximal expiratory flow and exhaled volume during a forced expiratory vital capacity maneuver. The test is widely available, reproducible, and highly standardized in terms of performance, methodology, and equipment specifications.

Spirometry is a useful measure of severity of airflow limitation in asthma and is predictive of clinical outcomes. Normal standardized values for spirometry are well established for healthy, multiethnic populations. It is a safe and low-risk procedure that can be performed repeatedly for long-term monitoring.

The prebronchodilator response and postbronchodilator response maneuver involves a baseline spirometric value compared with a postbrochodilator spirometric value (ie, a repeat spirometry 15 min after 2-4 inhalations of albuterol). A measurement of forced expiratory volume in one second (FEV1) improvement of 12% or greater from baseline represents the presence of reversible airflow obstruction, which usually means that the patient has asthma. [7, 8] See the image below.

Spirometric data plotPre Bronchodilator FEV1 = 1.7 Spirometric data plotPre Bronchodilator FEV1 = 1.77 L, Post Bronchodilator FEV1 = 3.11 L approximating to 75 % change or airway reversibility.
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Peak Expiratory Flow

Peak expiratory flow (PEF) is a measure of maximum instantaneous expiratory flow and is used as an indicator of airway caliber in asthma. The advantage of peak expiratory flow is that the test can be self-administered on a daily basis, and the results can be recorded manually or electronically to attain the day-to-day or intraday variability. [8]

Peak flows may be used to monitor changes in airflow in response to treatment, in relation to exercise or other provocations, or to determine if shortness of breath (or other chest symptoms) is associated with a change in airflow measurement when trying to differentiate the various causes for shortness of breath (ie, cardiac vs pulmonary).

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Imaging Studies

Methacholine inhalation challenge provides a measure of airway responsiveness and has been used as one indication of whether a patient has asthma. A negative methacholine finding is a strong indicator that the patient does not have asthma, whereas a positive finding does not mean that the patient does have asthma. Methacholine challenges have proven useful in the evaluation of coughing patients and in evaluating vocal cord dysfunction. The challenge is performed by inhalation of increasing concentrations of methacholine, which is a cholinergic agonist, until the FEV1 falls by 20% or more. [8]

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Exercise Challenge

An exercise challenge measures air flow limitation after a maximum exercise test. A decline in FEV1 of 10% or more is a positive result. A positive test result is highly specific for a diagnosis of asthma in children but less so in adults. [8]

An exercise challenge measures air flow limitation after a maximum exercise test. A decline in FEV1 of 10% or more is a positive result. A positive test result is highly specific for a diagnosis of asthma in children but less so in adults. [8]

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Isocapnic Hyperventilation Challenge

Isocapnic hyperventilation challenge via the inhalation of cold, dry air induces bronchoconstriction in many people with asthma but is not considered a diagnostic test. Wide application of the test is limited by the lack of standardization. [8]

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Mannitol Challenge

The mannitol inhalation challenge is a promising method of assessing airway hyperresponsiveness by imposing an osmotic stress on the airways. It may induce bronchoconstriction by the same mechanism as exercise or isocapnic hyperventilation. [8]

Mannitol is used for the same indications as methacholine but is easier to perform and less dangerous for personnel who may themselves have airway overreactivity.

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Other Tests

Allergy skin testing

Adults with asthma often have an allergic trigger; therefore, skin tests are useful to determine the offending triggers. Strategies for allergen avoidance can then be developed, (eg, cat allergy, dust mite allergy).

Chest radiography

A chest radiograph may reveal hyperinflation of the lungs for a diagnosis of asthma. This test may be an important part of the work-up for differential diagnoses of other respiratory diseases.

Sinus CT scanning

A sinus CT scan may reveal evidence of rhinosinusitis or nasal polyposis, which might help with the diagnosis (eg, Samter’s triad asthma, aspirin sensitivity, nasal polyposis).

pH probe evaluation

This is a procedure that involves placing a pH probe attached to a monitor and measuring in real-time the amount of stomach acid that is refluxed within the esophagus. This may establish a diagnosis of gastroesophageal reflux disease (GERD) or laryngopharyngeal reflux (LPR) disorder as the etiology of chronic cough. GERD is also known to trigger and exacerbate asthma. LPR can cause postnasal drip, throat clearing, cough, and hoarseness. Lifestyle modifications include weight loss, low-fat diet, decreased caffeine and alcohol intake, raising the head of the bed about 6 inches, and avoiding meals 2-3 hours prior to reclining. Medications that reduce gastric acid secretion may also be helpful. Oral steroids may exacerbate GERD symptoms. [9]

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