How Should We Interpret Pulmonary Crackles?
How Should We Interpret Pulmonary Crackles?
Abstract & Commentary
By Allan J. Wilke, MD, Residency Program Director, Associate Professor of Family Medicine, University of Alabama at Birmingham School of MedicineHuntsville Regional Medical Campus, Huntsville. Dr. Wilke reports no financial relationship to this field of study.
Synopsis: Crackles occur commonly in cardiac patients without overt heart failure.
Source: Kataoka H, Matsuno O. Age-related pulmonary crackles (rales) in asymptomatic cardiovascular patients. Ann Fam Med. 2008 May-Jun;6(3):239-245.
Pulmonary crackles (the physical finding previously known as râles, French for "rattle") are commonly sought to confirm a diagnosis of heart failure (HF) and can be fine, medium, or coarse. However, crackles can occur in other diseases (interstitial lung disease,1 asbestosis,2 alveolitis,3 and bronchiectasis4) and in presumably normal people.5,6 Because HF is more frequent as people age, Kataoka and Matsuno wondered about the character of crackles in the elderly with stage A cardiovascular disease, defined as patients "at high risk for HF but without structural heart disease or symptoms of HF".7 High-risk patients include those with hypertension, atherosclerosis, diabetes mellitus, obesity, or metabolic syndrome or who are taking cardiotoxic drugs or who have a family history of cardiomyopathy. The authors conducted a prospective study at their cardiology outpatient clinic in Japan for fifteen months in 2005-2006. They recruited 385 patients without heart or lung complaints and no history of structural heart disease, decompensated heart failure, chronic or recent lung disease, or connective tissue disease. These patients had a physical examination, blood tests, electrocardiogram (ECG), and a chest x-ray (CXR). Patients with a creatinine ³ 1.2 mg/dL, an abnormal rhythm on ECG, or an abnormal CXR were excluded. The remaining patients had an echocardiogram (ECHO) and a serum B-type natriuretic peptide (BNP), to rule out structural heart disease and HF, and were excluded if the ECHO was abnormal or the BNP ³ 80 pg/mL. There were 274 patients left after this final screen. They ranged in age from 45 to 95 years (mean 69 years) with men making up 28%. Eighteen percent (18%) had a past or current smoking history. The patients were stratified by age, 45-64, 65-79, and 80-95 years. Ninety-two (34%) had audible crackles. The incidence of crackles increased with age, 11%, 34%, and 70%, respectively. Older patients were more likely to have bilateral crackles. In 79 (86%) the crackles were fine. Fifty-five patients with audible crackles had chest computed tomography (CT). In 20, the CT was normal and in 27, there were minimal changes noted. For comparison, 19 patients without crackles underwent chest CT. Five of them had minimal abnormalities. In a logistic regression analysis that looked at crackles with age, leg venous insufficiency, leg edema, serum creatinine, and BNP as independent variables; only age was an independent variable. They followed 255 patients for 6 to 12 months (mean 11 months). Congestive HF occurred in 3, acute coronary syndrome in 2, bacterial pneumonia in 5, and interstitial pneumonia in 1.
Commentary
In this population, audible crackles were fairly common, despite the absence of structural heart disease and symptoms of HF among the patients. This was a large study, but originated in a Japanese cardiology clinic, so the patients may not be representative of your population. This study doesn't tell us what the prevalence of crackles is in the general public, let alone in patients with decompensated HF. Assuming for the moment, however, that the findings are generalizable, how should we incorporate them into practice? Suppose you are examining an at-risk, but asymptomatic, 70-year-old patient who meets the definition of stage A and you hear crackles. The study suggests that this happens approximately a third of the time in patients with no structural heart disease on ECHO and a low BNP. The next step depends on your and your patient's risk aversion. If this were one of my patients whom I trusted to report back, I'd be comfortable following closely. On the other hand, if this were a new patient or one who didn't always return for follow-up, I'd order an ECHO and a BNP.
Pulmonary crackles (the physical finding previously known as râles, French for "rattle") are commonly sought to confirm a diagnosis of heart failure (HF) and can be fine, medium, or coarse. However, crackles can occur in other diseases (interstitial lung disease, asbestosis, alveolitis, and bronchiectasis) and in presumably normal people.Subscribe Now for Access
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