Putting it all together

[DancingFajitas]

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Hi, I seem to have a lot of trouble putting all the patient information together to come up with a differential. For instance, I can get a good history and physical exam, but after I check the lab work I'm sort of at a loss. I find it hard to go from a very superficial thought of ok this person has decreasing kidney function to oh its due to an interstitial nephritis. Does that makes sense? I guess you could say I'm having trouble connecting all the dots and wondered if anyone else has this problem and if so, how should I go about getting better at resolving it?

 

[haveaniceday]

Hi, I seem to have a lot of trouble putting all the patient information together to come up with a differential. For instance, I can get a good history and physical exam, but after I check the lab work I'm sort of at a loss. I find it hard to go from a very superficial thought of ok this person has decreasing kidney function to oh its due to an interstitial nephritis. Does that makes sense? I guess you could say I'm having trouble connecting all the dots and wondered if anyone else has this problem and if so, how should I go about getting better at resolving it?

Pocket medicine is great, for the kidney example: just go to the nephrology section and check out all the lovely tables with lab values and diagnostic criteria for things like interstitial nephritis, nephrotic syndromes, etc. Do this for everything, even when you think you know the answer and eventually you will know how to see red flags and patterns of lab values with symptoms and history, then you can make differentials pretty easily. Also, always remember big categories: drug-induced, infection, tumor, trauma and fill in the subcategories.

 

[AwesomO]

Everyone has this problem during third year. The important thing is to understand the pathophys behind the disease and have a step wise plan to evaluate your patient. Don't get caught in the "I'll just memorize the flow chart from uptodate" mentality. That does nothing for you because if you haven't seen a patient with say Renal failure in a month you will forget the entire flow chart. But if you understand why you are performing each step then you will never forget it.

Heres how I do it.

1) I Gather patient history and establish a DDx from that. After establishing your DDx I gather more history pertinent to my DDx.
2) I Perform the PE and look for things that confirm or rule out your DDx list
3) I Look over labs HOWEVER I know why I am ordering each lab and what I am looking for. I Don't just shotgun it and hope that it will all come together. Instead I have a plan on how I will use the lab values to justify my diagnoses. For instance I believe this patient has renal failure. And I want to know why. So I am going to order a US and bladder scan to rule out post renal obstruction. Then I will evaluate for prerenal by ordering the following tests. Then if neither of those are positive I will work the patient up for intrinsic renal failure and I will order these lab tests to confirm it.

Again have a plan of action and how you will justify your diagnoses.

If you can do that as a student you should be solid. As you go through the rest of your clinical rotations and eventually residency you will be able to expand your DDx from step 1 and be able to add to your DDxs based on step 3.

 

[BillyWitchDoctr]

I remember getting confused over lab results and reporting every abnormal lab in rounds. In retrospect, much of that was because I would chase every abnormal lab result without knowing its significance or how it would fit into the larger picture. I agree with the previous poster that it's important to know why you're ordering a lab or diagnostic test (or ask the M4 or resident if you don't) to know what's important to the differential.