00:01
All right then. Let's look at choledochal cysts.
00:04
These are congenital bile duct anomalies caused
by dilation and/or obstruction of the biliary tree.
00:11
And it's pretty straightforward once
you've identified what it is.
00:16
There are different types, type one to type five,
do you need to memorize this?
Absolutely not. Know that type one,
I guess, is the most common.
00:24
This is cystic dilation of the extrahepatic duct
and then, there are just a diverticulum of the common duct.
00:32
There is a choledochocele, that's a
duodenal wall common duct cyst.
00:40
So, at the point where it enters into the duodenum,
there's dilation of both the intra and extrahepatic ducts.
00:47
And then, least common overall, cystic
dilations of the intrahepatic ducts.
00:52
Again, do you need to memorize this?
No. Just realize that there's going to be pathology associated
with anything other than the nice
narrow normal common bile duct.
01:05
The epidemiology of this. So, it's relatively rare, one in 100,000 to 150,000 in Western industrialized countries
because of a genetic founder effect. It's more
common, one in 1,000 in the Asian population.
01:21
The male to female ratio is one to three to four,
so, females, much more common
and it's often diagnosed in infancy or childhood
because of obstruction of bile flow.
01:33
The etiology of this, the vast majority
of cases, it's congenital.
01:38
You were born that way because
of a developmental defect.
01:41
It can be rarely acquired after cholecystectomy,
so, damage to the bile duct wall
during removal of the gall bladder can lead
to the formation incidentally of a choledochal cyst.
01:56
It may be associated with
other anatomic variants.
01:59
So, if there is an abnormal junction
of the pancreas into the biliary tree,
if there are areas of biliary
or duodenal or colonic atresia
that may cause secondary choledochal cysts
and when there is a common bile duct
reduplication that is frequently
associated with these cysts.
02:22
How does it present? Well, it presents primarily
with obstructive jaundice and in infants,
because they can't really tell you what's
going on, there's a palpable mass.
02:34
There's hepatomegaly because you're not dumping
bile appropriately into the GI tract at the duodenum
because of obstruction due to the cyst,
the stools tend to be light-colored
and you will tend to have increased bilirubin
within the urine, so, it'll be darker urine.
02:51
And it's usually an incidental finding but it comes
to light because of the obstructive jaundice.
02:59
In children, usually, before their teenage years,
it will manifest with pain and nausea, vomiting and fever.
03:06
There'll be jaundice and with higher levels of bilirubin,
there may also be deposition of bile salts causing pruritus.
03:13
There will often be a palpable mass,
this dilated duct system can be felt.
03:18
And because of the location, you can also
get obstruction of pancreatic duct
release of contents and get recurrent
bouts of pancreatitis.
03:31
The diagnosis is largely clinical but we will
also do confirmatory laboratory testing.
03:36
The liver is doing its job.
So, it is conjugating the bilirubin just fine
but we have elevated levels of the
conjugated direct hyper - of bilirubin
because we're not able to get it into the
GI tract because it's obstructive.
03:52
We also see elevated alkaline phosphatase,
a good marker for either intrahepatic
or extrahepatic biliary tree obstruction
is the alkaline phosphatase.
04:02
Overall in most cases, there's not
much hepatocyte damage.
04:07
So, the transaminases, ALT and AST,
will be mildly elevated at most.
04:13
Ultrasonography will be your prime
way of doing the diagnosis.
04:16
You will see a dilated duct either intrahepatic,
extrahepatic or some combination of both.
04:22
And then, you can also do ERCP, the
endoscopic retrograde cholangiopancreatography
to actually visualize what is going
on in the biliary tree.
04:32
How are we going to take care of this?
Well, if there are complications with severe obstruction,
particularly, in infancy and/or severe
liver dysfunction, we can get coagulopathy
and we need to minimize those risks.
Not only that but with the choledochal cysts,
you will often get associated inflammation,
inflammation with regenerating epithelium
is prime territory for developing cancer.
So, there's a risk of cholangiocarcinoma.
05:04
Surgically, we will intervene.
We can cut out the cyst and do a primary anastomosis.
05:10
We can also do bile to enteric direct connections.
05:15
And with that, we finished our discussion of choledochal cysts.