We'll move on to our next case.
A 39-year-old woman presents to the clinic
complaining of bloody stools for one week.
She has a history of ulcerative
colitis, diagnosed at age 29,
well-controlled on a combination of
corticosteroids for flares and mesalamine.
Her last flare was several years ago.
She has not had abdominal pain, fevers,
diarrhea or other changes in bowel habits.
She does note an 8-kg unintentional
weight loss over the last 6 months.
Her vitals are normal,
physical exam is unremarkable.
Her labs show a hemoglobin
of 9 with an MCV of 78.
Her leukocyte count and
sedimentation rate are normal.
What is the best next step in diagnosis?
So let's look at some key features here.
She had new-onset hematochezia,
with a known history of ulcerative colitis.
She currently does not have
any features of a UC flare,
but her weight loss is a bit concerning.
And on her labs, she has a microcytic anemia
which can hint at long-standing blood loss.
In addition, her other labs, her white
count and her ESR are actually reassuring
against an ulcerative
colitis flare, at present.
So, as a quick aside, know that whenever a
patient describes a change in their bowel habits,
new-onset blood in their stools
or hematochezia or melena,
and iron deficiency anemia, you
should always consider colorectal caner.
This is a "must not miss" diagnosis and so you
should always make sure to screen for and rule this out.
So let's talk a bit more
about colorectal cancer.
Most colorectal cancers
Patient's presentation can vary quite a bit.
They may be asymptomatic and just
havecancer detected on a routine screening,
They may be symptomatic
with GI bleeding, abdominal pain.
you might first catch them
with iron deficiency anemia.
They may have change in their bowel habits, or
they may have unintentional wight loss.
Rarely, they may present as an
emergency with colonic obstruction
or perforation leading to peritonitis.
So the diagnosis is usually
made by colonoscopy
as this is the most sensitive and
accurate method for making the diagnosis.
And treatment as with all
cancers, depends on the staging.
When this is a limited stage cancer,
you can often do surgical resection.
but those who have more
advanced cancers may undergo
5-fluorouracil or radiation.
In addition, patients often
undergo post-treatment surveillance
with colonoscopies and CT of the chest
abdomen and pelvis at frequent intervals.
So we spoke a little bit broadly
about the staging of colorectal caner.
Here you can see that in stages
1,2,3 - the cancer has slowly progressed
to the layers of the mucosa,
submucosa and eventually into the muscle.
Once it has reached the serosa
or the outer layer of the colon wall
and penetrated into the other
organs or outside of the colon,
you now have stage 4 cancer.
So, what other inherited or existing
conditions can make somebody more likely
to develop colorectal cancer?
We spoke earlier about some broad risk factors that place
the general population at risk for colorectal cancer.
But there are also very many
familial cancer syndromes
that can lead to very
elevated risk of cancer.
We're not gonna go into too much detail
here but these are some the syndromes
you should know about
for test-taking purposes.
So the first is Lynch syndrome or Hereditary
Non-polyposis Colon Cancer.
This is from a mutation in a mismatch repair gene gene
that can lead to many types of cancers listed here.
Patients may also have FAP or
familial adenomatuos polyposis
This is from a mutation in
the APC tumor suppressor
which leads to many adenomas
forming throughout the GI tract.
You may also encounter Peutz-Jager Syndrome
which is a mutation in the STK11 tumor suppressor
which leads to the formation of many
hamartomas throughout the GI tract.
Another type of syndrome is Juvenile Polyposis Syndrome
which is a mutation in the TGF-beta signaling pathway
again leading to hamartomas
throughout the GI tract.
And lastly, an important one to know
about is ulcerative colitis or Crohn's disease,
so when patients have long-standing colitis
and inflammation that occurs over and over,
this places them at high-risk
for colorectal cancer as well.
So, how often should individuals with any of
these syndromes be screened for colorectal caner?
This is a complicated answer and I will
include the slide here for your reference.
What I would just draw your
attention to, however, is that
ulcerative colitis and Crohn's colitis patients
with these conditions should be screened
about every 1 to 2 years with a colonoscopy.
starting 8-10 years after they
were first diagnosed with IBD
So now that we've gone through
that, let's go back to our case.
We have a 39-year-old woman
with new-onset hematochezia.
She has a known
history of ulcerative colitis.
She was diagnosed 10 years ago at age 29.
She currently has no features of a UC flare and
her labs are mostly reassuring against this.
However she does now have
a new-onset microcytic anemia
which could be an iron-deficiency
anemia from long-standing blood loss.
So the next best step in diagnosis is a
colonoscopy to evaluate for a colorectal cancer,
Thank you very much for your attention.