Diagnosis of Key Liver Diseases – Hepatitis A, B, C vs. Alcoholic vs. Ischemic (AST vs ALT Labs)


okay so welcome to another MedCram
lecture we’re talking about liver function tests it’s the third lecture
where we could talk about actual diseases and I wanted to break them up
into acute liver diseases chronic and finally cholestatic so let’s get started
okay so here I’ve made a table of some of the characteristics of hepatitis in
the acute form let’s talk about hepatitis A remember that hepatitis A is
an oral transmission so you don’t get it by blood you get it by so I’m not
washing their hands and then getting into the food and then there’s some sort
of a fecal oral transmission you get it but because this is the liver you’re
gonna see an increased amount of alt over ast both go up but you’re gonna see
more of an alt type of bound up over the ast and so how are you going to diagnose
this remember it’s the eye G M anti hepatitis A virus okay so that’s how you
make the diagnosis now with hepatitis B on the other hand it’s not oral but it’s
intravenous intravenous or body fluid okay and in this situation it’s very
similar to hepatitis A and that the alt is going to be higher than the ast
because this is the liver that’s being attacked and not muscle or something
else with hepatitis B remember there’s different antigens there’s surface
antigens and there’s cor antigens and that’s important because if you get an
immunization you’re gonna have antibodies against the surface antigen
so if I could draw a little example here if this is the virus particle the blue
is the surface and the core is the green the core is the actual viral particle so
when they give a vaccine they’re just using the blue portion of the virus the
non-infectious so you’re gonna have antibodies that are gonna be made
against the surf antigen so you so if you have an
immunization you should be surface antibody positive but you should be core
antibody negative because they never gave you the core and so what this means
is that you should the IgM antibody to the hepatitis B core antigen should be
positive if you actually have the infection let me restate that here so
the i GM core antibody is positive again the IgM antibody to the hepatitis B core
antigen is positive that’s called the IGM anti-hbc c stands for the core and
you should also have it positive to the surface antigen so both of those should
be positive okay because in an actual infection you’re getting the surface and
you’re also getting the core so you should have i GM you should have both of
those so again the IgM antibodies at the hepatitis B core antigen and to the
hepatitis B surface antigen both should be positive okay
what about hepatitis C again hepatitis C is actually a little bit more chronic
and so you’re not gonna see as much of an increase here but again the key point
here is the ast is gonna be less an increase than the alt again this is
intravenous drug use or IV DEA abuse okay there’s other things that are
associated with this like tattoos also sharing razors multiple sex partners
these sorts of things can increase the risk of spreading hepatitis C now how do
you check for that it’s very simple it’s simply the aunty HCV antibody into IgM
you could also check for the hepatitis C virus RNA within the first three months
of the exposure you should have an antibody reaction though
alright let’s talk about alcohol now whereas before the alt was higher than
the ASD because this is the liver be aware that in alcohol they’re about the
same or you might even see that the ast is going to be higher than the alt isn’t
that interesting and obviously here instead of intravenous drug use we’re
gonna get alcohol use so that’s that’s obviously very important difference
there obviously you want to make sure that there’s not other things going on
here so the diagnosis is basically based based on history
what about ischemic now remember an ischemic you’re getting no blood flow to
the liver so the liver is gonna be really upset with that and it’s gonna
tell you that and so what you’re gonna see is humongous raises in the ast and
the alt and we’re talking several thousand here okay so they really go up
in ischemic disease and obviously you’re gonna have blood pressures here in the
50s / 30s or something really bad like that or a code situation and again
you’re gonna be ruling out other things here but if you see this go up and shoot
up pretty quickly I want you to think of ischemia and you just again it’s gonna
be based on the the history okay let’s talk about the chronic diseases now
obviously you can get chronic hepatitis B and C and you don’t get chronic
hepatitis A or it’s very rare so I left those off of here basically they look
identical as to the acute situation except the liver enzymes are not as
elevated let’s talk about Nash probably one of the most common it stands for
non-alcoholic steatohepatitis basically these patients are fat obese so you’re
talking about patients with for instance the metabolic syndrome insulin
resistance hypertriglyceridemia and that in the history you’re going to basically
get for the diagnosis is that of exclusion you certainly don’t want to
just look at someone say they’re fat and that’s why you’ve got Nash but these
type of patients what do they look like these patients are liver patients so
they’re going to have a slightly increased alt over that of the AST but
the alt will be higher than the but it’ll be it’ll be elevated now as we
said with alcohol it’s very it’s just backwards the alt is high but the ast is
what’s elevated and again the history is going to be that of EtOH and a guess
it’s also gonna be of exclusion you want to just make sure that you’re not just
as subscribing somebody to the old alcohol reason for their liver disease
make sure that even though they’re drinking make sure you rule out the
other things autoimmune hepatitis that’s that’s the reason why we need to rule
this out if you have a middle-aged woman who drinks a lot you certainly don’t
want to say that it’s due to just for drinking because it could be due to
autoimmune disease these are the type of patients that get autoimmune disease
these young women so because it’s an autoimmune hepatitis again it’s in the
liver they’re gonna have a higher alt than ast so the history in this is that
they’re young women that’s the type of people who get these autoimmune diseases
and the thing here that you got to know is this this is for boards and it’s the
anti smooth muscle antibody if that’s positive it’s gonna be very difficult to
say that this is all related to alcohol disease so look for positive Auto
antibodies anti-nuclear antibodies but specifically the answer they’re looking
for is anti smooth muscle antibodies ok hemochromatosis this is uncommon in
women it’s usually because why they have periods and they lose iron so they it’s
very hard to store up with iron but the history here is that it’s typically in
men and what are we gonna see here well if you take the ferritin level and the
iron saturation that’s the where you take the iron the serum iron and divided
by the TI BC you’re gonna get something greater than 55% and usually you’re
ferritin level is greater than a thousand so you’re off the charts with
this and of course the history is that of something called bronze diabetes and
this shows up on test a lot and the reason does is because it’s going to
very specific presentation basically iron infiltrates a lot of the endocrine
organs of the body the iron infiltrates the pituitary okay so they can get
pituitary problems it infiltrates the pancreas so what do they get they get
diabetes it infiltrates the heart so they get what and CHF or some sort of
constrictive cardiomyopathy okay so look for this patient with diabetes who has a
bronze look to themselves now there’s an iron metabolism deficiency
that you should know it is on chromosome six and how do you remember that I
remember that iron comes in a 2 plus form and also in a 3 plus form the
Pharos and the ferric form and I know that 2 times 3 is equal to 6 so that’s
how I remember it’s on chromosome 6 I don’t think they will ever ask you that
but you can certainly impress your friends with that bit of knowledge
ok what about Wilson’s disease I think Wilson’s disease showed up on a famous
television show once and those of us who studied knew what the diagnosis was
before the end of the show you’re gonna have increased alt and ast the history
here with Wilson’s disease is that they’re young they get this kind of
korea form movement disorder and psychiatric disease but the key here is
this thing’s called the kaiser ka y ser Fleischer f.l.e.i.j.a sche are rings so
google that or look that up on the internet and see what kaiser Fleischer
rings are in the eyes and you will see that and the key here is not a high but
a low zero plasmon and why is that because it’s trying to suck up all the
copper this is a abnormal copper deposition so you get hemolysis and
actually you get a low alch foss and a low cerumen plasmon ratio okay and now
the one that’s most near and dear to my heart is alpha 1-antitrypsin these
but typically we see this with patients with lung disease remember antitrypsin
alpha-1 antitrypsin is an enzyme that is in your lungs it’s made in your liver as
well and what it does is it protects these elastase –is from breaking your
elastin fibers and so if you don’t make alpha 1-antitrypsin you have something
called alpha 1-antitrypsin deficiency and you tend to get emphysema more
quickly well that’s not the only thing that can happen you can get a buildup of
this abnormal protein in the liver and you’ll see these past positive paths
positive granules in the liver and you will get liver disease it’s a very kind
of a low-level liver disease so you’re not going to see it going very high but
on the history you’re gonna have COPD asthma certainly if they smoke very
early in life if they don’t smoke they’ll have COPD later in life in the
scratch your head say well how did I get the COPD I’ve never smoked well get an
alpha 1-antitrypsin level the thing that you should know there is the worst form
of it is the p i– z z allele okay and the normal is the mm
but the z z is the worst and that’s homozygote recessive okay so
this is autosomal recessive autosomal recessive inheritance and so how do you
make the diagnosis you don’t obviously do a liver biopsy first off but you
simply get an alpha 1-antitrypsin level and then have them see a liver doc okay
so let’s talk about next the characteristics of cholestatic liver
disease and for that join me for the next lecture number four