ValueChain_OganGurel

52 KoreaVoices
It is said that the only things
guaranteed in life are “death and
taxes” and while some have been
known to avoid taxes, death will
eventually claim us all. Indeed,
not all of us are doctors but we all
have been, or will be, patients. For
the past five years I had had the
privilege of presenting the Mini-
MD, a comprehensive overview of
all of medicine (some call it a “Mini
Medical School) for healthcare
professionals worldwide, teaching
the program at Samsung, both
in Korea and in the U.S., and
then more broadly in Singapore,
Melbourne, Italy and later this month
(October 22nd) back in Seoul. The
program is designed for those in
the healthcare field, though without
formal medical training: they include
hospital executives, pharmaceutical
and medical technology leaders,
government policy makers,
biomedical scientists and engineers,
healthcare designers, lawyers, etc.
But if you think about it, medicine,
for the main reason given above,
that it affects us all, is of deep,
enduring interest. The human body
holds endless fascination, and even
more so in the case of disease, and
acutely so when it affects us. So
how is it that doctors think? How
do they arrive at diagnoses? Is it
a science—or an art? Some of us
may just defer to doctors and leave
it at that, but most, especially as we
approach our inevitable mortality
are more than curious. So I thought
I would share here, for the benefit
of my fellow KBLA members and
wider audience, some of the distilled
“pearls of wisdom” on how doctors
think. Reading further may not save
your life, but, who knows, it might
very well do just that …
From the General to the Specific
Obviously, we will not cover all of
medical school in the space of a
few paragraphs but there are some
general principles that doctors
follow, some of it learned explicitly,
others more subconscious. One
is the concept of proceeding from
the general to the specific. While
the structure of medical practice
is often oriented towards specialty
care (indeed, many people complain
that some doctors seem to care only
about specific diseases and organs,
and not the whole person), medical
education is fundamentally general
and broad. In the United States,
medical school is actually called
“undergraduate medical training”,
much to the chagrin of college
graduates who have already gone
through “undergraduate” training,
only to have to do it again!! What
that means is that all doctors are
actually trained to be generalists
– there is no “medical school for
the liver” or “medical school of
cardiology”. Rather, we are exposed
to all the aspects of medicine, from
superspecialized surgery all the way
to the basics of labor and delivery
in obstetrics, all in an effort to instill
the principles of care for the whole
patient, and in the scientific sense,
to minimize diagnostic mistakes that
arise from overspecialization.
Here’s an example. Say you have a
cough: a lay person may logically
conclude that the problem is with the
lungs. It is the lungs, after all, that are
producing the “cough”. Of course,
most will do a Google search and if
you go to some reputable site you’ll
find a long list of possible causes
(“etiology” is the technical term)
of cough. But a doctor — a good
doctor — will be trained to look at
the broad range of possibilities first,
and then narrow these down more
specifically based on information,
data, results of tests, and so forth.
The Logic of Medicine:
How Doctors Think
Ogan Gurel, MD
CEO, NovumWaves
ogan.gurel@kbla.info

53KoreaVoices
So, roughly speaking, there are
actually three anatomic sources
of cough (we would call this the
“differential diagnosis of cough”) and
they would be the lung (no surprise),
the heart, and the stomach. [More
on this later, but the heart can
cause a cough via “heart failure” in
which fluid backs up into the lungs,
thereby causing the cough-inducing
irritation, and the stomach can incite
cough through gastroesogpheal
reflux, namely stomach acid getting
into the esophagus and creeping
up to the lung.] Of course, not
everything causes cough. It would
be very unusual indeed if one of
the anatomical causes of cough
were your left big toe. So part of the
science and art of medicine – the
reason for the long training, is how
general to be and how quickly to get
specific. Too general, and you waste
time, money, and create potential
risk for patients, investigating things
pointlessly. Too specific, and you run
the risk of misdiagnosis some, if not
most, of the time.
This principle of general to specific
also pervades the process of
medical diagnosis, indeed the entire
engagement with the patient. As
most people know, on first encounter
with a doctor, typically (and there are
exceptions such as emergencies,
general screening tests, etc.)
the relationship begins with a
conversation (formally called “taking
the history”). “What brings you to
the hospital?” or “What is bothering
you today?” are typical questions
that are posed to elicit what is
called the “chief complaint”. After
taking the history, a physical exam
is performed which begins to get
more specific in its focus, after which
blood tests are taken, again guided
towards more specific results,
and perhaps some other tests or
imaging studies. The sequence is
not random. One does not show up
at the hospital and immediately get
a test for, say thyroid disease, and
then a colonoscopy, and eventually a
doctor shows up and gets around to
asking what the problem is. From the
general to the specific is the guiding
principle. It may not always happen
that way, but that is the ideal.
Framing the Problem: Dualities
So let’s say you’ve seen the doctor
with your cough and they determine
it’s not the heart (for example, some

54 KoreaVoices
specific heart related tests come
back negative) and neither do you
have reflux (heartburn). So it’s likely
to be a lung problem. Lung disease:
now that, too, is fairly broad and
often, when faced with a broad
spectrum of possibilities, doctors
will frame the problem in terms
of a duality, namely two contrary
possibilities. It turns out that there
are two types of lung disease:
obstructive lung diseases and
restrictive diseases. And this way
of categorizing medical knowledge
as dualities is extremely common.
For example, there are two types
of heart failure: systolic heart failure
(poor pumping of the heart with
blood) and diastolic heart failure
(poor filling of the heart with blood):
even though both are “heart failure”,
they have entirely different causes
and treatments. Stroke comes in
two varieties: ischemic stroke (lack
of blood flow to the brain) and
hemorrhagic stroke (bleeding or too
much blood to the brain), for which
the treatments are obviously quite
different. In fact, the treatment of
ischemic stroke, life saving in that
instance, could very well be fatal if
applied to a patient with hemorrhagic
stroke. So these dualities are not just
theoretical constructs but have very
real implications and consequences.
Back to the cough. In obstructive
lung diseases (such as bronchitis
or asthma) it turns out that the lung
volumes are actually larger than
normal, which makes sense as the
obstruction, such as with narrowed
airways, prevents air from being
adequately blown out. In fact,
doctors can often spot a patient,
even without tests, as potentially
having obstructive lung disease, if
they show up with a large “barrel”
chest, a consequence of a chronic
(long-term) obstructive process.
But again, more specific tests,
such as spirometry or so-called
“pulmonary function tests” (the one
in which you are told to breathe in
and out of a tube) can pick this up
more specifically. Restrictive lung
disease, which is generally rarer,
is characterized by smaller lung
volumes, as you can see from the
diagram. Again, as with the heart
failure or stroke examples, the further
diagnostic steps and treatment
options are entirely different for these
two categories.
Dualities are very important in
providing structure to medical
knowledge and framing the problem.
The offer certainty, an “either / or”
kind of thinking that is very important
in proceeding to the beyond
just the vague amorphousness
of “lung disease”. Knowing and
understanding these dualities is a
key part of medical training.
Prior Probabilities
Of course, medicine, and life
in general, is not so “black and
white”. As is commonly taught,
medicine is not an exact science
and while frameworks such as the
ones I shared above offer some
degree of certainty, nothing is
more certain than the possibility of
uncertainty. But there is a science
of uncertainty, which falls under the
general scheme of statistics, but
in the case of medicine (and other
fields) deals more specifically with
the concept of “prior probabilities”
codified in a mathematical law called
“Bayes Theorem”. Without being
too technical, Bayes Theorem (the
science of “conditional probabilities”
or “prior probabilities”) basically
states that the probability of an
event (say a certain diagnosis)
is related to conditions that are
related to that event. Let’s look at
the probability of a pregnancy test
being positive. If one already knows
that the patient is male (e.g. a “prior
probability” obtained via the history
or observation), then we already
know, we are certain, that is, that
the probability of the pregnancy test
being positive is zero. Of course,
that is an extreme example but most
of medical diagnosis is influenced
strongly by such thinking. This
is one reason why the “general”
approach outlined above, and, in
particular, good “history-taking”
is so essential to getting the right
diagnosis. Lay persons often thing
that one single blood test “clinches”

55KoreaVoices
the diagnosis, but in reality is a
combination of data points, each of
which create the circumstances for
greater certainty (e.g. “conditional
probabilities”) which would otherwise
be impossible. It’s one of the reasons
why we don’t screen everybody
for cancer, for the same reason we
don’t screen men for pregnancy.
The prior probability of a 5-year
non-smoker getting lung cancer
is so infinitesimally small that it is
far outweighed by the risk, cost,
and inconvenience of submitting
that toddler to a CT exam. It may
sounds like an oxymoron, but prior
probabilities ensure certainty.
The Importance of Talking to the
Patient
As mentioned, history-taking is
absolutely essential to proper
diagnosis. Not only does it ensure a
“general approach” to the patient,
as outlined earlier, but it also obtains
a wider matrix of information, the
“prior probabilities” in which more
correct, more efficient diagnosis
can be made. There is a saying
in medicine, perhaps not always
adhered to, that the “history”, more
than any blood tests or other fancy
investigations, provides roughly
“80%” of the diagnosis. Some say it
accounts for even more.
Let me share a story. I worked for
four and a half years at Samsung, at
SAIT, the central corporate research
lab, which also housed the CTO
function for Samsung Electronics.
Obviously, we had some of the
world’s top scientists and engineers,
and our focus was very much on
technology. For a leading tech
company like Samsung, technology
is the mantra, the way, the be all
and end all. So imagine the surprise
when one of my technologically-
oriented co-workers comes to me
first thing in the morning, saying,
“when I woke up I had this terrible,
terrible, pain,” while pointing and
rubbing the middle of his back on
the right side. “What happened?!”
I asked. “Did you fall down?”
“Where you in a fight?” (these are
obviously diagnostic questions
to rule out a traumatic etiology).
He answered that he had gone
to a company dinner the night
before, drank a lot (my mind starts
thinking “dehydration”) and he was
awakened with this terrible pain,
which he had never experienced
before. And so this is what I told him,
“I think you have a kidney stone, and
you should go to the doctor to have
that evaluating.” Even though I was
fairly confident of the diagnosis (e.g.
all the prior probabilities pointed to a
highly positive outcome on an x-ray
for kidney stone), the reason to go
to the doctor would be to determine
if it was large (e.g. > 5mm) or small
(< 5mm) — again, “duality” — which
would imply a different treatment
approach.
Rather than thank me for my
advice, my colleague looked at me
with disbelieving eyes: “How do
you know that? You didn’t do any
tests? How do you know I have
a kidney stone?” I answered that
while confirmatory tests would be
required, the history (he scoffed)
strongly suggested that. The next
day, after he returned, feeling much
better, by the way, I asked him, “So
what was the result?” He sheepishly
looked down: “a kidney stone.” After
that, he seemed convinced that I
was some sort of magical “seer” who
could somehow conjure up diagnosis
from nothing. In reality, I was just
applying the power of “talking to the
patient”, taking a good history, which
is often nearly all a doctor needs to
establish the diagnosis. It’s actually
one reason why we ourselves (and
doctors themselves) are often the
poorest diagnosticians when it
comes to ourselves. Sometimes
we are in our own denial and so we
don’t take the right history, we don’t
look generally enough, to get it right
when it comes to our own illnesses.
Treatment: Is it Medical or is it
Surgical?
Among the many dualities in
medicine, one of the most
fundamental is that of diseases being
“medical” or “surgical”. There is a
very profound difference between

56 KoreaVoices
the two that is not just theoretical,
not just practical, in terms of the care
of the patient, but even pervades
the entire structure of medicine and
the healthcare industry. Roughly
speaking, “medical” diseases
are those that are generalized or
“systemic” throughout the body and
are treated by medicines, namely
drugs, while “surgical” diseases are
those that are localized or regional,
and require some sort of intervention
for their treatment. Many diseases
can actually be both “medical”
and “surgical” either at the same
time or at different stages in their
development. Early-stage cancer,
for example, being localized is often
treated surgically, with removal of
the tumor, while late-stage cancer,
with disseminated metastases
throughout the body, may no longer
be surgically treatable but rather
requires chemotherapy.
In the case of the kidney stone
example above, I mentioned that
5mm was the rough “cut-off” point
for determining whether the disease
was medical or surgical. Less than
5mm implies that the stone can likely
be passed (usually quite painfully)
through aggressive fluid therapy
alone (e.g. medical treatment).
Experience has shown that stones
greater than 5mm are unlikely to
spontaneously pass and thereby
require some form of intervention,
such as a catheter, stent, shock
wave lithotripsy, or even “cutting”
surgery, to remove.
So now you can think like a doctor:
your colleague comes to you
complaining of back pain. You ask
general questions, to rule out a wide
a wide spectrum of causes, you
talk to the patient to find out more
background, compiling these among
“prior probabilities”, come up with
the leading diagnosis of “kidney
stone” and then think, “is this
medical or is this surgical?” There’s
obviously a lot more to how doctors
think but these are a sampling of
some of the core principles. You can
find out more at the Seoul Mini-MD
coming up on August 22nd at COEX
(see: http://www.seoul-mini-md.
com/). The program will help you
be a better health professional and,
who knows, a little knowledge and
understanding of doctors think may
even save yours or one of your loved
ones life one day?
About the Author
Ogan Gurel, MD, is the CEO /
Founder, NovumWaves and former
Visiting Professor, Samsung
Advanced Institute of Science &
Technology. He is an
Honorary Fellow, University of
Melbourne and an advisor to
numerous healthcare startups and
companies.

ValueChain_OganGurel

More Related Content

What's hot (9)

Viewers also liked (14)

Similar to ValueChain_OganGurel (20)

More from Ogan Gurel MD (11)

ValueChain_OganGurel