November 10, 2009

Snap, Crackle, Pop.

One of the difficult things about learning the art of the physical exam early in medical school is learning to differentiate pathology from normal. I remember when we first were instructed on the lung exam. We learned about these ambiguous terms... rales, rhonchi, egophony, stridor, tactile fremitus. I learned that you could have crackles in your lungs, and set about listening to the lungs on all my patients very closely. And I discovered a funny thing. Vesicular (aka normal) breath sounds can sound kinda-crackley if you listen close enough. All my patients started having crackles. I asked a doc I was working with one day "What do crackles sound like? Because it sounds to me like all my damn patients have crackles."

Eventually, I had a patient with real crackles, and like anything else with the physical exam, once you listen and touch enough normal patients the pathology begins to jump out at you. But this story isn't about that patient. It's about a patient I saw earlier this week, a 65 year old man with chronic kidney disease and congestive heart failure who presented with shortness of breath. He was actually my first patient I've seen with 3+ pitting edema, I damn near lost the entirety of my index finger into his left shin. But this story is about crackles, and I noticed a certain quality to his voice as I was talking to him in the exam room. No hoarseness or changes in phonation. But it sounded like someone had just poured themselves a bowl of rice krispies and set it in the corner. The snap, crackle, pop became more audible with each labored breath he took. For some reason, the moment brought me back to my early days of listening to the lungs, waiting for total silence and listening intently, hoping to catch a crackle or two in passing. And here I had a patient sitting in front of me with so much fluid brimming out of his lungs that I didn't even have to place a stethoscope on him to hear the crackles.

Sadly, in this economy, I'm not sure Kelloggs is looking for any new spokespersons anytime soon.


Brett said...

Fascinating! I heard that the use of stethoscopes is declining since they are not so effective on obese people. Is this true? Have you ever noticed this effect (an attenuated sound signal) in practice?

I'm not in the medical field but I really do enjoy these "insider insights". Thanks.

MedZag said...

I think it would be a sad day if the stethoscope became "out of favor" in medicine. I think we're seeing a swing back in the pendulum. In the 90's medicine came up with all these highly sensitive and specific diagnostic tests which some clinicians came to lean on more than they probably should have. Now the field is broke financial and everything is about "cost effectiveness." Well there's really nothing more cost effective than a physical exam. You can get an enormous about of information quickly and effectively with a good PE.

But yeah, you can't hear (or feel) very much effectively in the morbidly obese. I can't tell much on the heart exam except that heart sounds are present and the rate and rhythm are regular. Can't hear any murmurs, rubs, or gallops. Same goes for the abdominal exam... might be able to feel the liver if its huge but no much else. You can do a pretty decent lung exam though.