Abnormal Liver Enzymes – A Clinical Approach

Lecture by

Professor David Twedt

Reviewed by

Chantal Celindano

So, does anyone else look at blood work results, see elevated liver enzymes and grimace just a little? Well, after you listen to this lecture by Dr David Twedt, you will be filled with confidence – and will worry a little less! In this presentation, Dr Twedt breaks elevated liver enzymes down using case studies and useful summary slides, enabling you to easily discern whether you have a case of liver disease proper, or perhaps a situation whereby the liver is just an innocent bystander of nearby disease. There is also a really helpful flow chart, presented 27 minutes into the lecture, which can be used as a guide for when we should be rechecking those enzymes (did you know, it can take two months for the liver enzymes to return to normal?!). This lecture also covers what an elevation in ALT vs an elevation in ALP means, what to be concerned about when GGT rises, and when to do further testing like bile acids. Do you know how many biopsies to take of the liver, when to think of copper storage disease, or how to treat chronic idiopathic hepatitis and monitor it adequately? Well this lecture has all of the answers, and much more!

Takeaway Pearls:

ALT and AST are liver ‘leakage’ enzymes, which can rise with any kind of liver necrosis or degeneration, administration of steroids or other drugs. They do NOT go up with old age!
ALT is considered significantly increased if it is double the normal reference range or chronically increased without an obvious cause.
Cat’s don’t get steroid hepatopathies, only dogs do.
It can take up to 2 months for elevated liver enzymes to return to the normal range.
Even topical or ocular steroids can cause an increase in ALP!
Animals with liver disease actually have a higher protein requirement and diet should be considered a part of treatment in these cases.
If the dog is asymptomatic, repeat liver enzymes in two months time and consider testing bile acids if they are still elevated.
Do bile acids when you are looking for occult underlying liver disease or considering a portosystemic shunt. There is no need to run this test if the dog is icteric. Always do a fasted and a two hour postprandial sample, as some patients show abnormalities with only one result, and others with both.
A FNA of the liver for cytology only matches up with histopath results from a biopsy around 30% of the time!
Biopsy samples should be obtained from three different liver lobes. Check coagulation profiles first, but these don’t often bleed excessively, and if they ooze you can employ electrocoagulation or gelfoam. There is a nice video on how to do this. Once you have the tissue, culture it, measure copper levels (in a red-topped tube) and do histopathology.
Keep in mind that chronic hypoxia, such as small dogs with tracheal collapse, can result in elevated liver enzymes!
Primary gastrointestinal disease can also result in liver enzyme elevation. Dysbiosis (bacteria imbalance) and inflammatory bowel disease can result in secondary changes in the liver and resolve with dietary manipulation! Winning!
Chronic hepatitis can be linked to copper disease, infection (e.g. leptospirosis), phenobarbital or chronic NSAIDs use, genetics (Dobermans, Labs, Westies, Dalmatians, Cocker spaniels, Standard Poodles and English Springer Spaniels) and idiopathic or immune-mediated conditions. Idiopathic chronic hepatitis occurs mainly in older females with persistent ALT elevation. Instead of using steroids in these cases, Dr Twedt recommends treating with cyclosporin, so that liver enzymes can be followed, as well as using ursodiol and denamarin.

Dr Twedt is an outstanding presenter, and this lecture provides a sound framework from which to tackle those tricky liver cases!

Liked the review? Watch the full lecture here!