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Approach to a patient with Fatty Liver.pptx
- 1. Approach to a patient with Fatty Liver Dr. Nazish Butt MBBS, FCPS, MACG Dr. Nazish Butt Associate Professor Head of Gastroenterology Department Jinnah Postgraduate Medical Centre, Karachi General Secretary of Pakistan Society of Gastroenterology
- 2. How Prevalent Are NASH and NASH With Advanced Hepatic Fibrosis?
- 3. Worldwide Prevalence of NAFLD and NASH Steatohepatitis “NASH” Cirrhosis Normal Liver Steatosis “NAFL” NAFLD Fatty liver with significant inflammation and hepatocyte ballooning Increasing fibrosis leading to cirrhosis, hepatocellular carcinoma Fatty liver with trivial or no inflammation and no hepatocyte ballooning Slide credit: clinicaloptions.com Worldwide prevalence: 25%1 3% to 5%1 1% to 2% at risk* 1. Younossi. J Hepatol. 2019;70:351. 2. Kabbany. Am J Hepatol. 2017;112:581. *Based on analysis of NHANES data estimating 1.74% prevalence of NASH with advanced fibrosis.2
- 4. Fatty Liver Is Not Benign: Mortality Associated With Isolated Steatosis and NASH Analysis of all-cause mortality in 6 separate studies among patients without NAFLD vs with and without NASH ‒ NAFLD determined by ultrasound; NASH determined by liver biopsy No NAFLD (14.5-yr follow-up) NAFL (Steatosis) (13.3-yr follow-up) NASH (Steatohepatitis) (13.0-yr follow-up) Liver related Cardiovascular Other Mortality (%) 40 20 0 80 60 100 Bril. Endocrinol Metab Clin North Am. 2016;45:765.
- 5. How does NAFLD occur? • We aren’t exactly sure….
- 6. Normal Liver NASH NAFL “Simple Steatosis” Cirrhosis Clin Med (Lond). 2015 Apr • Sedentary lifestyle • High fat diet • Insulin resistance • Obesity • Oxidative Stress • Mitochondrial Dysfunction • Inflammatory Cytokines • Gut Dysbiosis, Endotoxins 1 2 “Two Hit” Hypothesis
- 7. What populations are at higher risk for NAFLD? • Risk Factors • Obesity, (↑ risk with advancing BMI and waist circumference) • Impaired fasting glucose • Hispanic heritage • Male gender • Advancing age • Coined the “Hepatic Manifestation” of Metabolic syndrome
- 9. How do you diagnose NASH?
- 10. • NAFLD a common diagnosis in patients with “incidental” abnormal liver enzymes such as ALT, AST[1-3] However: • Liver enzymes may be normal in ~ 80% of NAFLD patients[4,5] • ALT and AST not sensitive for NAFLD/NASH • Poor correlation between ALT and histology • ALT typically decreases with advanced fibrosis • As NASH progresses, AST/ALT ratio may increase (ie, ALT < AST) • Histology severity similar in NAFLD patients with normal vs abnormal liver enzymes[6-8] Normal Liver Enzymes Do Not Rule Out NASH 1. Daniel. Am J Gastroenterol. 1999;94:3010. 2. Skelly. J Hepatol. 2001;35:195. 3. Pendino. Hepatology. 2005;41:1151. 4. Browning. Hepatology. 2004;40:1387. 5. Dyson. Frontline Gastroenterol. 2014;5:211. 6. Mofrad. Hepatology. 2003;37:1286. 7. Sorrentino. J Hepatol. 2004;41:751. 8. Fracanzani. Hepatology. 2008;48:792.
- 11. How do you diagnose NASH? • Liver biopsy is the GOLD standard Do we have to do a biopsy on EVERYONE with fatty liver disease??
- 12. Clinical Predictors of Fibrosis • NAFLD Fibrosis Score (Age, AST, ALT, PLT, BMI, Albumin) • BARD Score (AST:ALT ratio, DM, BMI) • Fib-4 (age, ALT, AST, platelet count) • Presence of underlying risk factors (diabetes, hyperlipidemia, etc)
- 15. How do you Diagnose NASH? Non-invasively? • Vibration Controlled Transient Elastography (Fibroscan) • MRI Elastography (MRE) • Multiparametric MRI (LiverMultiscan)
- 16. Imaging for Identifying Advanced Fibrosis in NAFLD: Vibration-Controlled Transient Elastography • Accurate in detecting advanced fibrosis • Most reliable in ruling out advanced hepatic fibrosis (NPV stronger than PPV) • Predicts risk of decompensation and complications • Correlates well with portal pressure F1/2: Perisinusoidal Portal F3: Bridging Fibrosis F4: Cirrhosis FibroScan Value (kPa) Fibrosis Stage F0: Normal 6-8 8-12 12+ 6
- 17. 1) Review of clinical history 2) RUQ US 3) Full liver enzymes evaluation (rule out viral hepatitis, autoimmune disease, hemochromatosis, etc The Lowly fellow’s algorithm for elevated LFTS and/or concern for NAFLD: 1) Imaging assessment of Fibrosis (Fibroscan or MRE) 2) Review clinical risk Continue LFT evaluation as necessary Continue liver enzyme evaluation as necessary No liver Biopsy Liver biopsy for staging US(+), no clear alternate etiologies US(-) Elevated Liver stiffness Clinically increased risk Normal liver stiffness Encourage lifestyle modifications ?Vitamin E Weight loss accountability Continue to reassess need for staging (if not already done) NASH Non NASH NAFLD
- 19. Conclusion Patients with NAFLD have little knowledge about the disease they harbor, its nature, its implications, and the need for intervention. This represents a major gap between disease causality and its understanding and eventual outcomes that can only be bridged by introducing policy in the form of clinical guidelines, awareness campaigns, civil society involvement, and healthcare system reforms including registries. For the moment, further exploration of the awareness of and attitudes towards NAFLD is needed to develop effective strategies for combating this disease in Pakistan.
Editor's Notes
- NASH, nonalcoholic steatohepatitis.
- NAFL, nonalcoholic fatty liver; NAFLD, nonalcoholic fatty liver disease; NASH, nonalcoholic steatohepatitis.
- Fatty liver itself is not a benign disease. This is an analysis of 6 studies with follow-up between 13.0 and 14.5 years. As you can see, patients who have steatosis have an increased mortality and that increased mortality is specifically related to an increase in cardiovascular mortality. When you go to the true patients with NASH, these patients not only have an increased risk of cardiovascular mortality (red) but also have an increased risk of liver-related mortality (blue).
- It is also interesting and important to remember that if you look at NAFLD patients as a whole group, the vast majority of these patients will have normal or near normal liver enzymes. Liver enzymes do not actually correlate with histology; they are not very sensitive for diagnosis of NAFLD and NASH. In fact, when you look at those patients with fatty liver disease with normal liver enzymes or with elevated liver enzymes, their histology is not that different. In patients with fatty liver disease, as the disease progresses and they develop more fibrosis (scarring of the liver), the levels of ALT will decrease such that the AST to ATL ratio will reverse, with higher AST vs ALT. An AST to ALT ratio > 1 is usually associated with alcoholic liver disease. In this context, when you have a patient with NAFLD who starts with a lower AST to ALT ratio which then flips to a higher AST to ALT ratio, that indicates there may be progressive liver disease and fibrosis. This change is one of the clues in clinical practice that you can examine.
- Transient elastography uses sound waves to measure the stiffness of liver tissue. MR elastography uses magnetic resonance imaging to capture images of shearwave propagation in the liver producing an elastogram that maps liver stiffness values with high resolution
- Vibration-controlled transient elastography (VCTE) is a noninvasive technology that is based on ultrasound waves. In general, the entire procedure will take no more than 10-15 minutes. The VCTE will give you 2 numbers. One is a measurement of the stiffness of the liver, as measured in kPa, and the second is called CAP, which is a measure of the amount of fat in the liver. As an example, if you have a patient with a liver stiffness of 8 or higher, that patient probably has significant fibrosis, bridging fibrosis, and possibly cirrhosis. If you have very high numbers—13, 14, or 15—there is a high probability of cirrhosis. I use a CAP score of > 245 to suggest that the patient may have fatty liver at the same time. But from the 2 numbers that you get, I think it is important to pay a lot more attention to the stiffness. Keep in mind that this is not a perfect test; it does have some flaws. However, it is a reliable test in terms of excluding advanced fibrosis. So the negative predictive value is higher, and it does correlate well with some complications of cirrhosis such as portal hypertension. It is also important to remember that VCTE does not measure cirrhosis or scarring of the liver; it just measures stiffness of the liver, which correlates with staging of fibrosis. There are a number of situations where it may not perform well. If a patient has severe visceral obesity or has had a meal before the test, it can have some false positivity and negativity. Note that there are newer modalities, new probes, that have been developed that are very accurate in assessing liver stiffness even in the context of visceral obesity. The advantage of VCTE is that you can have this done in your clinic. In fact, there are portable machines that can move from one place to another place. There is also MR elastography, which is based on MRI technology, which I think is probably more accurate. In that test, the stiffness is also measured as kPa, but the scoring is different; a score of approximately 3.2 or higher suggests advanced fibrosis. However, it is more expensive and not readily available in all practices. If you are looking for a test that is point of care and easily accessible, VCTE is the one that we use most of the time. If you are looking for accuracy, for example in clinical research or clinical trials, consider MRE or MR elastography.