Hi, my name is Jill Beavers-Kirby, and
today we're going to talk about
pathophysiology. So what is pathophysiology?
Well, it's broken down
in Greek words, one meaning pathos which
means disease, and physiology which
means the study of all structural and
functional changes in cells, tissues and
organs. Anytime you see -ology on the end
of a word, you want to know that
that's the study of something.
are cellular and structural changes within
the body and the effects that
these changes cause on somebody. So then
what is disease? Disease is a
pathological disorder. It is not caused from
trauma or injury. It can affect all the
structures in all parts of an organism.
It is, once again, not
a result of a physical injury. So the features
of disease include etiology, the
pathogenesis, the morphological changes, and
the clinical signs and symptoms.
So etiology. Once again we have the -ology
ending on the end, so etiology is the
study of why things are. So etiology can
be biologic such as bacteria or
viruses, they can be physical such as from
trauma or burns, they can be
chemical from alcohol or poisons, it can be
inherited such as some types of heart
disease can be inherited from family members,
or they can be congenital which
simply means that they've been there since
birth. So what is pathogenesis?
Many diseases are thought to be of a
genetic predisposition or from an
environmental cause. So from an environmental
exposure, or it's just
something in your genes or your DNA. So pathogenesis
and etiology, even though
they mean two different things, you might hear
these two words used
Just remember that etiology is the study of
the cause of the disease whereas the
pathogenesis is what is causing the disease.
You don't really need to get too
hung up if they are used interchangeably.
So morphology. Remember, we have that
ending on the end, that means study of.
This is the study of the function of cells or
tissues. Morphologic changes, when you hear this,
is referring to the changes in
the cells or the tissues. Histology is the study
of the actual individual cells.
So sometimes when describing a disease, you
might hear that there are
histological changes. This simply means that
the changes are at a very cellular
level. Sometimes histological changes are used
to determine the cause of diseases.
Other manifestations of diseases are symptoms.
Symptoms can be hard on
patients and on caregivers, because symptoms
are whatever the patient tells you.
Things like pain, dizziness, we can't see these.
We just have to go by whatever the
patients tell us. Whereas signs are things
that we can actually see and
measure, such as somebody's temperature or swelling
or redness, also known as
erythema. But remember, symptoms you can't see,
it's just strictly based on what the
patient tells you.
Signs, if you think of like a stop sign or a
yield sign on the road, these are
things that we can see and measure. So we
often hear about the signs
and symptoms the patient presented with were --
Syndromes, and you'll hear this term
also, is the collection of the signs and symptoms.
So an example of a syndrome is
Down syndrome or irritable bowel syndrome.
Those are just a couple of examples. You can
also have complications which are
unfavorable developments of a disease. So a
person with chronic obstructive
pulmonary disease, a complication of that
might be shortness of breath and
wheezing, whereas sequelae are the natural
progression of the disease. So as
end-stage renal disease, meaning end-stage, you
don't make any urine
any more, you can end up on dialysis. That's
a sequela of that disease.
So diagnostic tests. These will also help us
with the pathophysiology. So diagnosis is
the process of listening to the patient
talk about their signs and symptoms, gathering
a full history and physical,
and utilizing the testing that we have
available to us.
Diagnosis as I stated, requires a thorough
history and physical exam.
I can't stress this enough. You really have
to listen to the patient,
listen to what they are saying. It is also important
to listen to what they are not
saying. You know, are they not complaining of
abdominal pain even though they are
complaining of nausea. So developing a diagnosis
requires using all of your
senses, looking at the patient, listening
to the patient,
utilizing tests that you have available, and
weighing all this evidence. You want to
make a diagnosis, a healthcare diagnosis, based
on what is most easiest.
So if somebody comes in, sniffles, sneezes,
runny nose, low grade fever, they
probably have a cold, correct? They probably
don't have lung cancer. So you
always kind of want to think of the most simplest
reason to explain all of
the information that you've gathered from the
patient. Age, gender, race and
lifestyle can also aid you in your diagnosis.
So for example, a man comes in
with a large belly, saying he's having belly
pain and cramping, I'm not going to
to think he's pregnant because he's a man, this
is impossible. So there are
age-related diagnoses, gender-related diagnoses.
not one diagnosis that fits everybody. So when you
use a diagnostic test, you have to
take in to the quality of the test. So there are
certain terms that we use to
describe how good a test it is. One of these
terms is validity. Simply wrote
down, how valid is this test?
Is it measuring what it says it's measuring?
So is a milliliter measuring a
milliliter? Another term we use to describe
tests is reliability. How reliable is it?
So this is how reliable are these results? If
I repeat the results and you
repeat the test, are we getting the same result?
There are two other terms that we
use to describe the quality of diagnostic tests.
One is specificity.
So this is simply how specific is this test? So if
a test is highly specific and it
comes up with a positive result, the chances are
that the test is positive.
For example, if you do a blood pregnancy test
on a patient where you're looking
for the beta hCG protein in the blood, that is
highly, highly specific. So if
that comes up positive, the chances are that
you're pregnant. Not 100%,
but very highly likely that you're
pregnant. The sensitivity is how
sensitive the test is. So for example, a highly
sensitive test would be good in
ruling out a disease. So once again, talking
about the serum pregnancy test or
serum blood test, if your beta hCG is negative,
chances are you're not pregnant. So what is evolution
of a disease? You're going to hear these
terms used a lot. So acute means the acute phase
of the disease. It doesn't
mean that the disease is a cute little disease,
it means the disease is
new and it's been newly diagnosed, and it's in
the beginning phase. You may or may not hear
of a subacute phase. A subacute phase is the
phase between the acute and the chronic.
So the disease is leaning towards the chronic
phase of disease but it's not
quite there yet. So if you think about somebody
who has got kidney disease and is
going into kidney failure,
the initial insult when their creatinine
was elevated would be considered the acute phase.
Then as their kidney
function leans more towards end-stage dialysis ,
that would be the subacute
phase. The chronic phase is the continuing, long
lasting phase of
the disease. So once again, the end-stage renal disease,
where a patient may or may
not be receiving dialysis three times a week. You
can also have flare ups which
are called acute on chronic. You will hear this a
lot used with somebody who
has COPD. So they've been managing their breathing
issues fine, fine, fine, and then
all of the sudden spring time comes, things pollinate,
they get acutely short of
breath or they get upper respiratory infection.
This causes an acute
exacerbation of their chronic symptoms. And finally,
the natural history of the
This is simply talking about the natural prognosis,
how it developed, how it's
going to flow through someone's life, and more
likely than not how the disease
will end. Prognosis defines the probability
of the outcomes of the disease.
Thank you. This has been Jill Beavers-Kirby