Very useful findings. Crackles are quite common in congestive heart failure (CHF). Yet, if present only after recumbent position, they may have even better diagnostic/predictive value.
What are posturally induced crackles (PICs)?
Very useful findings. Crackles are quite common in congestive heart failure (CHF). Yet, if present only after recumbent position, they may have even better diagnostic/predictive value.
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What about crackles of congestive heart failure (CHF)?
They are very similar to those of pulmonary fibrosis: profuse, fine, high pitched, and late inspiratory. Both predominate in gravity (and posture) dependent regions. In fact, they are quite difficult to separate on auscultation, even though a differentiation can usually be made on clinical grounds (or by using computerized sound analysis). Still, the examiner should be aware of their similarity, especially when considering diuresis. As a rule of thumb, bibasilar fine crackles should suggest heart failure only in patients with no other indication of pulmonary disease. What are the characteristics of crackles in pneumonia?
Although Laënnec considered them very similar to those of hemoptysis and pulmonary edema, their characteristics depend very much on the stage of pneumonia, as demonstrated by computerized sound analysis. In the acute setting, crackles are predominantly coarse and mid-inspiratory, resembling those of bronchiectasis. During recovery, however, they tend to become shorter, more end inspiratory, and thus similar to the crackles of pulmonary fibrosis. Is there any diagnostic clue that may suggest pneumonia in ambulatory patients?
In patients with cough, fever, sputum production, and dyspnea, the findings of egophony, bronchial breath sounds, dullness to percussion, diminished breath sounds, tachypnea, and crackles all argue (in decreasing order of importance) in favor of a diagnosis of pneumonia. What are the most valuable bedside predictors in pneumonia patients?
Hypothermia and hypotension, both strong predictors of poor outcome. Improvement of blood pressure and fever—together with lowering of cardiac and respiratory rates—is instead a favorable predictor. Finally, oxygen desaturation has little prognostic value in hospitalized patients. What about the presence of diminished breath sounds?
It also can occur in pneumonia, but usually in the setting of a concomitant pleural effusion. What is the time course of these findings?
Variable, with crackles and diminished breath sounds usually appearing first, bronchial breath sounds and egophony developing 1–3 days after onset of symptoms (i.e., cough and fever), and dullness to percussion (plus increased tactile fremitus) occurring even later. This time lag usually allows for x-ray to preempt diagnosis, thus making exam irrelevant, since early detection by imaging translates into early institution of antimicrobial therapy, which in turn leads to aborted or never-developed physical findings. Hence, physical exam may be entirely normal in patients with pneumonia. What are the traditional findings of pneumonia?
Increased tactile fremitus Dullness to percussion Bronchial breath sounds with late-inspiratory crackles Egophony Yet findings are often scanty or even absent. This argues against the original claims of physical diagnosis founders, that the bedside exam could identify any patient with pneumonia. The reason for this discrepancy is that modern physical exam is judged against extremely sensitive gold standards, such as roentgenograms and CT scans. Conversely, the 19th century gold standard was autopsy, which selected the most severe forms of pneumonia, and thus the ones more likely to be associated with abnormal physical findings. |