Does anyone have an easy method or know of a resource when trying to figure out breath sounds and forming this into a differential? I tend to get confused between Rhonchi, Rales, Wheezes, stridor, bilateral vs. unilateral, what you'd hear in asthma vs. pneumonia, etc. Combine this with the fact that the heart and lungs are so intimately related, and I sometimes get overwhelmed in figuring out the origin of the pathology. I feel like First Aid doesn't cover this that well, but maybe that's just me.
Also, any advice for XR? Not sure how people study for this, but X-rays of the lungs/heart/abdomen are the bane of my Step 1 existence.
It would be useful to define what is the cause of each breath sound and also know what each is associated with.
Wheezing happens mostly during the expiratory phase, is associated with airway obstruction and asthma is the most common cause.
Rhonchi is a manifestation of obstruction of medium sized airways-- the bronchi and most often associated with secretions. For rhonchi think bronchiectasis (CF) or COPD (smoker).
Crackles or rales are a sign or alveolar disease. Whatever disease process that fills the alveoi with fluid can cause crackles. Could be pneumonia or pulmonary edema (cardiogenic or non cardiogenic). Interstitial fibrosis can also cause crackles.
Stridor is a high pitched sound that usually occurs during inspiration (as opposed to wheezes) and this is associated with upper airway obstruction, at the level of the larynx. Stridor needs to be evaluated immediately as it may signal impending complete airway obstruction and resp failure. I think as far as step goes the most likely cause of stridor would probably be parainfluenza croup.
Egophony; hearing AH instead of EEE when patient phonates EEE, is suggestive of lung consolidation, such as what occurs with lobar pneumonia. This is useful to differentiate between alveoli fluid and interstitial fibrosis crackles. Egophony is present in alveloi fluid crackles but not in interstitial fibrosis crackles.
Tactile fremitus is increased in consolidation (pneumonia), and decreased in pleural effusion.
Lack of breath sounds might suggest a pleural effusion or a pneumothorax.
Dullness on percussion- Pleural effusion, which on CXR looks like opacification, with a fluid level (meniscus sign).
Hyperresonance on percussion- Pneumothorax with hyperlucency on CXR and contralateral deviation of mediastinal structures (if tension pneumothorax).
Anyways, I know this isnt complete but its a start. For more on chest and abdomen X-rays, I would make sure to learn the most common signs of things like pneumothorax, CHF, atelectasis, pleural effusion, small bowel obstruction, large bowel obstruction, volvulus, colorectal cancer, kidney stones and other common things. Might sound like a lot, but I think xrays/CTs on step should be pretty straight forward and knowing the very basics should be sufficient.
yessirr!!!!
