ABSTRACT: The diagnosis of asthma in older persons may be complicated by a number of factors, including atypical presentations and comorbid conditions, such as chronic obstructive pulmonary disease and congestive heart failure (CHF). A high index of suspicion for the diagnosis of asthma is warranted in patients with isolated dyspnea or cough. The diagnosis should be based on demonstration of reversible airway obstruction on pulmonary function tests. Additional tests that may be useful in the initial evaluation include chest radiography, arterial blood gas analysis, and standard electrocardiography. CT may help exclude pulmonary embolism and certain neoplasms that can masquerade as asthma. High-resolution CT scans are valuable when pulmonary function test results are consistent with interstitial lung disease. When the diagnosis is uncertain, measurement of brain natriuretic peptide can help distinguish between obstructive lung disease and CHF. (J Respir Dis. 2008;29(10):391-396)
With the aging of the US population and the increasing prevalence of asthma, the number of adults older than 65 years who have asthma will increase considerably in future decades.1 These seniors with asthma may present with the typical symptoms of cough, wheeze, and dyspnea or with isolated complaints of fatigue or functional decline (Table 1). Common misdiagnoses include chronic obstructive pulmonary disea
se (COPD), congestive heart failure (CHF), depression, and "aging."2 Available data suggest that asthma is both underdiagnosed and misdiagnosed in seniors.2-4
Failure to pursue the diagnosis of asthma in symptomatic patients may result in lost treatment opportunities that could slow progression of the disease. Underlying medical conditions that mimic asthma or trigger asthma symptoms, such as gastroesophageal reflux and rhinosinusitis, may also go undetected.5 The presence of comorbid conditions, the decreased perception of bronchoconstriction in the elderly, and the propensity of older persons to minimize and adapt to symptoms with lower levels of functioning all contribute to underdiagnosis of asthma.6 These factors may partially explain why the elderly present later after the onset of symptoms and with more advanced airway obstruction than younger asthmatic patients.7,8
Because of these issues, we have developed an algorithmic approach to facilitate the diagnosis of asthma in this vulnerable population.
MAKING THE DIAGNOSIS
Atypical symptoms
Atypical presentations are common in older patients.9 Questioning older patients about shortness of breath, wheezing, chest tightness, and cough may help identify many cases of asthma. However, a high index of suspicion for the diagnosis is warranted in patients with isolated dyspnea, cough, or fatigue. Asthma must be considered if there is a history of allergic disease earlier in life; active atopic diseases, such as rhinosinusitis or eczema; or peripheral blood eosinophilia.
Wheeze, cough, and dyspnea may also be present in patients with COPD, CHF, hypersensitivity pneumonitis, sarcoidosis, and other conditions in which endobronchial airflow obstruction is present. Thus, there is a developing consensus that the diagnosis and assessment of the severity of asthma in elderly patients should be based on demonstration and quantification of reversible obstructive airway disease by pulmonary function testing.
