In this episode of PodMD, Gastroenterologist and Hepatologist Dr Matt Kitson will be discussing the topic of evaluating abnormal liver function tests (LFT). We discuss important initial clinical factors to assess for in patients, different patterns of LFT derangement, warning signs a GP can look out for, and more.
- Transcript
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*As always, all in this PodMD podcast is intended for health professionals and the comments are of a general nature. Information given is not intended as specific medical advice pertaining to any given patient. If you have a clinical issue with one of your patients please seek appropriate advice from a colleague with expertise in the area.
Today I’d like to welcome back to the PodMD studio Dr Matt Kitson.
Dr Matt Kitson is an experienced Gastroenterologist and Hepatologist providing care in the Eastern and Southeastern suburbs of Melbourne, and also in Gippsland.
Matt studied Medicine at the University of Queensland, graduating with Honours in 2001 and obtained his FRACP in 2011. He was awarded a PhD by Monash University in 2015, and his thesis evaluated Vitamin D status in liver disease.
Today, we’ll be discussing the topic of evaluation of abnormal liver function tests.
*We do hope you enjoy this podcast but please remember that the advice here is of a general nature and is not intended as specific advice about a given patient. The views and opinions expresssed in this podcast are those of the doctor, not PodMD. If you do have a patient on whom you require specific advice, then please seek advice from a colleague with appropriate expertise in that area.
Matt, thanks for talking with us on PodMD today.
Matt: Thanks very much for having me on the podcast.
Now the topic of today’s discussion is evaluating abnormal liver function tests. How would a patient with abnormal LFTs typically present?
Matt: Yeah, abnormal function tests often present as an incidental finding, so patients are often asymptomatic, and they have blood tests for routine screening or other reasons. Occasionally, the patient might have symptoms such as pruritus, jaundice, systemic viral symptoms, but the majority of the time, they’re completely asymptomatic.
Question 1
What are some important initial clinical factors to assess for in a patient with abnormal LFTS?Matt: I guess the first thing to consider is “is this a new problem, or is this a worsening of previous abnormal liver function tests?” So, having access to previous liver function tests is very helpful, and I’ll often spend a significant amount of time looking into this and trying to access previous blood test results. Sometimes this is easy, as it’s been done with the same laboratory, but sometimes you have to really put a significant amount of work finding out previous blood test results.
I think the the pattern of the liver function test abnormality is very important as well, and we’ll talk a little bit about that later. It’s important to know exactly what medications the patient is taking, prescribed medications as well as over-the-counter medications and specifically paracetamol. It’s also really important to know about any herbal or dietary supplements that the patient might be taking. What their weight and their body mass index is, whether they they have diabetes or if there’s a family history of diabetes and also alcohol consumption are all very important things to know about. It’s also important to evaluate for other symptoms such as abdominal pain, nausea, vomiting, systemic viral symptoms and peritus as well. I mentioned about family history of diabetes, but also knowing if there’s a family history of autoimmune disease and hepatitis B as well is very helpful.Question 2
Can you tell us a bit about the different patterns of LFT derangement that might be seen?Matt: So there are quite a few different patterns that can be seen. The first one is is the bilirubin elevated or not as if this is the case, it should really raise eyebrows, especially if the bilirubin is 40 or above, there might actually be some significant pathology that needs to be thoroughly evaluated quite quickly. If the bilirubins are elevated, you also need to know if the patient has pruritus or abdominal pain. The most common cause of an elevated bilirubin is something called Gilbert Syndrome or Gilbert syndrome, depending whether you want to sound French or not. With this, the bilirubin or even normally in the 20s or the 30s and you can confirm this by checking their unconjugated bilirubin. But if the bilirubin is higher than that, in the 40s or above, there may be biliary obstruction, drug-induced liver injury, or severe acute hepatitis, and these are things that need to be evaluated for quite quickly.
The second pattern that is commonly seen is an elevated ALT, which is also known as a hepatocellular pattern. It’s important to know that a true normal ALT is 30 or less for men and 20 or less for women. I guess in the back of your mind you need to know what level of ALT, elevation should you really be concerned about. An ALT that’s consistently elevated 100 or more really requires a specialist review to try and determine the cause as it’s a risk factor for progression of liver disease and if the ALT is 300 or more, really the patient needs to be seen sooner rather than later by a specialist.
With ALT elevation, the most common cause of this is non alcoholic fatty liver disease, which has now been renamed MASLD, which is known as metabolic dysfunction-associated steatotic liver disease, it’s a bit of a a mouthful there but the ALT elevation with this common condition which is present in about 20 to 30% of people, is usually less than 100. Itt’s much less common for this to be pushing the ALT above 100 or more. Also need to consider about whether viral hepatitis is present or potential for underlying autoimmune liver disease, and this is especially the case if the ALT is 100 or more and also celiac disease, which is present in about one in 70 people can also cause an ALT elevation.
The other thing to look at if there’s a significant elevation of ALT is, is there atypical lymphocytes on their full blood count as this can be indicative of an acute EBV or CMV infection. It’s important to know about if the patients on statins and also how much paracetamol they’re taking. The other little takeaway for this, that’s important to know about, is if abdominal pain is present in the ALT is in the hundreds, then you really need to consider is there choledocholithiasis present because often you actually see an ALC elevation when this is the case.
The third thing is an isolated Gamma GT elevation. This is a fairly easy one and of less concern. Obviously you need to know how much alcohol the patient’s taking, and especially if their MCV is elevated and the AST is greater than the ALT. The other common cause of this is certain medications and especially anti epileptic drugs such as phenytoin and carbamazepine.
The final thing I’ll mention is an elevated alkaline phosphatase, also known as a cholestatic pattern. If the alkaline phosphatase is elevated with a normal bilirubin, then this is really a marker of what’s called intrahepatic Cholestasis. But we also often see the Gamma GT and the alkaline phosphatase elevated in fatty liver, even if the ALT is normal. The other thing to be aware of with an elevated alkaline phosphatase is that this can be elevated due to the bone ISO enzyme, so I’ll often to alkaline phosphatase isoenzymes testing to determine whether it’s the liver isoenzyme or the bone isoenzyme. The final takeaway for an elevated alkaline phosphatase is that you need to consider if primary biliary cholangitis is present if your patient is a female and aged above 40.Question 3
Are there any useful online resources to help if medications are suspected as being a cause?Matt: There’s this great online database called Livertox, so if you go to livertox.org this is an online encyclopedia of pretty much every medication and its risk of hepatotoxicity. So don’t hesitate to jump online and look into this.
Question 4
What basic investigations are helpful initially?Matt: The majority of patients with abnormal liver function tests will need imaging, which is most commonly done with an upper abdominal ultrasound, and this gives us important information, such as the architecture of the liver, which can indicate underlying chronic liver disease. It can also tell us about the presence of any hepatic steatosis, although, be aware that an ultrasound can only detect steatosis of about 5% or more, so you can have very mild fatty infiltration and this may not be picked up by liver ultrasound.
We can also evaluate for liver lesions, the presence of gallstones, and if their biliary tree is dilated. So it’s a very helpful initial, non-invasive investigation. Also, the other thing to do is to check anyone who has an elevated ALT, should have their hepatitis B and C serology checked, regardless of whether they have risk factors for chronic viral hepatitis or not, because sometimes you might find something significant there.Question 5
What subsequent investigations are sometimes necessary?Matt: So if all of the initial tests don’t yield a cause, often we’ll do a liver screen looking for autoimmune or genetic causes of liver disease, and that can sometimes give us an idea of what’s going on. The other thing that can also be helpful, especially if there’s chronic elevation of liver function tests, is considering a non invasive assessment of liver fibrosis with a fibroscan machine. Often a lot of radiology places will have the ability to do what’s called shear wave elastography with more modern ultrasound machines or you can also refer to the local tertiary referral centre hospital, and they’ll often have a fibroscan machine, which can assess via transient elastography. The other thing that can also be helpful, although often this will be ordered by a specialist, is ordering an MRCP if they have a cholestatic liver function test pattern or if choledocholithiasis is suspected.
Question 6
Are there any warning signs that the GP can look out for and, ultimately, when should they be referring?Matt: So to summarise, I think the warning signs to look out for is a bilirubin 40 or more is really important to identify, if the ALT is consistently 100 or more as well, these patients need to be seen by a specialist. If the patient has abdominal pain and the ALT’s in the hundreds, then have a high index of suspicion for Colorado Cholelithiasis as being the cause.
Question 7
Matt, thank you for your time here today in the PodMD studio. To sum up for us, could you please identify the three key taker messages from today’s podcast on evaluating abnormal liver function tests?Matt: Take home message number one is that often finding the cause of abnormal liver function tests is like doing detective work and having access to previous LFTs or tracking those down is a very helpful tool. The second take-home point is the medication history is really important, especially the time of commencement of medications and what that timing is relative to the onset of abnormal liver function tests and also doing a thorough history taking about the use of herbal and dietary supplements, it can be very helpful as well. The 3rd and final take-home point is if the bilirubin is significantly elevated and I guess I have put a cut off of 40 or more, or if the ALT is significantly elevated that is 300 or more, which is 10 times the upper limit of normal or more then get appropriate imaging, often with an ultrasound or maybe a CT, and then refer on fairly quickly to the appropriate specialist.
Thanks again for your time and the insights you’ve provided. We always appreciate having you on the podcast.
Matt: Thanks very much.
