Liver Disease: Introduction and Commonly Used Liver Test

00:01 Hello! Welcome to Hepatobiliary diseases.

00:04 Here our topic at first will be viral hepatitis.

00:08 Remember that when we discuss hepatitis there could be many, many causes as we go through our topic of hepatitis.

00:17 At first it will be viral, but it could be autoimmune.

00:19 It could be alcohol, could be many causes do not always assume that it's viral.

00:25 Let's begin. The liver tests that you should be familiar with, known as your liver function tests include the following.

00:34 In hematology, we talked about bilirubin quite a bit, and here we talk about bilirubin as being part of prejudice or pre hepatic jaundice.

00:44 Hepatic jaundice and post hepatic jaundice.

00:47 Here with bilirubin accumulating.

00:51 Not exactly sure as to what part of bilirubin metabolism could be affected.

00:55 What do you mean, Dr. Raj? Watch. Say that you brought bilirubin.

01:01 Unconjugated type.

01:02 An indirect is what is what we use clinically.

01:06 And you bring this lipid soluble substance to deliver with the chaperon.

01:10 The albumin then drops it off.

01:12 Obviously the first step here by the liver's to make sure that it conjugates it correct.

01:18 What does conjugate mean to you.

01:20 It means a turning something that's lipid soluble into water soluble.

01:25 And why is that our objective.

01:27 Why is this objective so important.

01:29 Because we're trying to at some point get this bilirubin out into excretion.

01:33 And in order for you to get bilirubin into the urine, you must conjugate it at some point in time. My point is this when you have liver disease, maybe perhaps the enzymes have been affected.

01:46 The enzyme responsible for conjugation is UDP glucuronosyltransferase.

01:50 Without going into that type of detail.

01:53 If the liver is damaged sufficiently and the enzymes are not working properly, then what component or what fraction of a bilirubin are you then noticing? Good the unconjugated bilirubin.

02:07 Or let's say that there is enough damage to the liver that now at this point the entry point into bile has been blocked.

02:17 But remember bilirubin is part of your bile as well.

02:21 So therefore now you could get conjugated.

02:24 However, the type of bilirubin that you're looking for laboratory wise could be conjugated. So what's the point.

02:31 And what are you paying attention to on your boards and on your wards? You can have a mixed picture of bilirubin.

02:40 Or called jaundice.

02:42 When you have liver disease, keep that in mind.

02:45 If that is not clear, make sure that you go back and take a look at proper and full bilirubin metabolism.

02:51 So what I have just discussed with you medically, clinically makes a lot more sense.

02:58 Next. My topic is liver function tests.

03:01 What if the liver is damaged sufficiently enough where the liver inadequately doesn't put out albumin? Welcome to something like cirrhosis.

03:15 Anything that causes end stage liver disease, or if there is sufficient liver damage, there's every possibility that albumin could be diminished.

03:23 Mm. What does albumin contribute physiologically in your circulation.

03:28 What part of your starling's forces.

03:31 Good oncotic pressure.

03:33 Thus, if albumin is not present, oncotic pressure drops.

03:38 Where is my fluid now? Escaping into intra tissue.

03:44 There are two tests or coagulation tests.

03:48 You notice I didn't say platelet test, right? What's the platelets platelet test that you're extremely familiar with or should be.

03:55 That's bleeding time and hemodynamics.

03:58 We talked about platelets.

04:00 I'm not going to bring that up here.

04:02 But either platelet dysfunction or quantitatively you have thrombocytopenia.

04:06 Then the bleeding time will be affected.

04:07 Here. However the coagulation factors that you should be familiar with include well from the liver what are you synthesizing to seven, nine and ten divided by k dependent factors on one end pro coagulation.

04:25 And what are the two anticoagulation factors that deliver produces? Protein C and protein S.

04:33 From henceforth.

04:35 Whenever you think about the liver, remember there are pro and anti coagulant factors that are in fact being secreted from it.

04:42 Correct. Next.

04:45 Clinically speaking, which of the two tests are you going to measure of your coagulation to tell you that the liver may or may not be functioning properly? It's PT prothrombin time.

04:58 Inr international normalized ratio.

05:02 What is it that you want to know in terms of its actual time? 11 to 15 seconds.

05:09 You know that for your boards you'll be in good shape.

05:12 Thus, if the liver is not functioning properly, the synthesis of your coagulation factor drops.

05:19 What then happens to your PT? Increases. Have alt.

05:26 This is your alanine or alkaline alanine type of aminotransferase.

05:30 So you have the two transaminases Alt and AST.

05:34 And the ratio here do become very important since our topic in this section is going to move into viral hepatitis, would you please be able to tell me which one of these transaminases would be elevated? More so would it be Alt or AST in viral hepatitis? Good alt.

05:53 Just to make sure that we're clear and to have a little bit of fun with this.

05:58 I want you to toast to assist.

06:01 Toasting. What? Alcohol. So whenever you have alcohol induced hepatitis there, the assist will be increased versus alt.

06:12 2 to 1 ratio.

06:14 Continue. When does alkaline phosphatase come into play? And do not confuse the ALP with Alt.

06:24 Alp alkaline phosphatase would come into consideration if the biliary tree has been affected. Obviously, the liver and the biliary tree are one unit.

06:38 You cannot separate one from the other if there's enough damage that's taking place to the liver. Understand that you are then going to affect your bile or biliary canaliculi. And so therefore may cause damage or injury to the biliary system, therefore increasing ALP.

06:56 Just to make sure we're clear, would you tell me as to what other set of diseases under a different type? But still ALP would be used for obviously bone disease.

07:08 Now the two types of liver function are p t and albumin.

07:11 So those are the two that you definitely want to focus upon.

07:14 But absolutely understand that each one of the components that we're dealing with here will play an important role, so that you can diagnose your patient properly.

07:23 The other is only signify altered function and do not correlate with overall synthetic activity of the liver. So of all of these, the two that actually give you proper functioning of liver include p, t and albumin.