Intro To Diagnosis

DIAGNOSIS — it’s all that really matters.  We can’t a treat a patient if we don’t know what they have.  And aside from antibiotics, surgery, maybe chemotherapy, much of our therapeutics achieves comparatively little.  Oh, I’m sorry.  Sure, you can accomplish other do-good things, like relieve asthma symptoms, control hypertension, ease gastroesophageal reflux, minimize pain, etc.  Certainly, treat with whatever miracle drug or lifestyle change you want, but please — always think to yourself, “Hey, Dude, what’s the DIAGNOSIS?”

Don’t aim to nail an immediate diagnosis; rather, generate a list of possibilities, the “Differential Diagnosis.”  Rule them out, especially deadly ones, while searching for a most-likely cause.  Start with a symptom, the “chief complaint.”  (What’s really a “Chief Complaint” after all?)

The goal of DiagnosisDude is to help us sort through Differentials.

Above all, determine the CHRONOLOGY of illness — is it acute, chronic, or recurrent; intermittent or continuous?  “Abd. pain x2 days” might mean a constant, steady ache, or twinges lasting 10 seconds only occurring a few times.  I’ve seen countless clinicians blow a diagnosis simply by failing to elucidate the evolution of a symptom.  Put yourself in a patient’s shoes — truly imagine how their illness has played out.  Pardon the cliché, but try to “feel their pain” (or vomit, diarrhea, whatever).

History-Taking is the major tool; it finds the diagnosis the vast majority of the time.  Physical exam, lab, x-ray, & other tests mostly reinforce & confirm diagnostic suspicions.

  • Obtain your history & other data systematically — NEVER ask a single question without knowing what you’re trying to rule out or in.
  • As you sort through the list of differentials, think of the natural history of each entity — is the patient’s presentation a possible course of untreated illness?  [or, of treated disease, if they’d tried a therapy].

VERY IMPORTANT — Always inquire if the patient’s illness is “getting better,” “getting worse,” or “staying the same”.  A progressive course is always more concerning.  If symptoms are resolving, there’s usually less to worry about.

Acute symptoms (i.e. recent onset) are the most dangerous.  This is counter-intuitive to many of my patients, who think that ten years of pain is worse than a few days’ worth.  Keep in mind conditions which can do a person in rapidly [the “DON’T MISS” category].

Beware of the Compromised Host — Much more likely to harbor serious illness.  They include:

  • elderly
  • debilitated
  • malnourished
  • alcoholics
  • renal failure
  • liver failure
  • active cancer
  • rheumatologic diseases
  • HIV / AIDS
  • sickle cell
  • immunosuppressive therapy
  • certain other chronic diseases

Also beware of the Severely Mentally Ill.  They have a very high threshold for tolerating pain and other symptoms, so when they present for care, take their complaint very seriously.  Unfortunately, they may also be unable to describe their symptoms well.

That’s it for here.  New readers might start by scrolling down the list of “Prior Posts” in the right-hand margin, & pick a symptom.

Enjoy, and Good Luck!

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