CBL 6 Fatty Liver (1) Flashcards
What’s the most common cause of liver disease in a developed world?
Non-Alcoholic Fatty Liver Disease (NAFLD)
Spectrum of NAFLD. (3) forms
- steatosis - fat in the liver
- steatohepatitis - fat with inflammation
- progressive disease may cause fibrosis and liver cirrhosis
What is thought to be involved in the pathophysiology of NAFLD?
NAFLD is thought to:
represent the hepatic manifestation of the metabolic syndrome -> hence insulin resistance is thought to be the key mechanism -> steatosis
What does Non-Alcoholic Steatohepatitis mean?
Non-alcoholic steatohepatitis (NASH)
- liver changes similar to those seen in alcoholic hepatitis in the absence of a history of alcohol abuse
Factors associated with NAFLD (5)
- obesity
- type 2 diabetes mellitus
- hyperlipidaemia
- jejunoileal bypass
- sudden weight loss/starvation
Clinical Features of NAFLD
- usually asymptomatic
- hepatomegaly
- ALT is typically greater than AST
- increased echogenicity on ultrasound
Do we screen for NAFLD?
What are the guidelines based on?
- no evidence to support screening for NAFLD in adults, even in at risk groups (e.g. type 2 diabetes)
- the guidelines are based on the management of the incidental finding of NAFLD - typically asymptomatic fatty changes on liver ultrasound
What’s ELF blood test?
Firstly, finding (usually incidental and asymptomatic) of fatty liver changes on USS -> then use ELF blood test:
- use of the enhanced liver fibrosis (ELF) blood test to check for advanced fibrosis
- the ELF blood test is a combination of hyaluronic acid + procollagen III + tissue inhibitor of metalloproteinase 1. An algorithm based on these values results in an ELF blood test score
What diagnostic tests/investigations do we do if ELF blood test is not available?
Non-invasive tests may be used to assess the severity of fibrosis:
- FIB4 score or NALFD fibrosis score
- these scores may be used in combination with a FibroScan (liver stiffness measurement assessed with transient elastography)
(this combination has been shown to have excellent accuracy in predicting fibrosis)
- Patients who are likely to have advanced fibrosis should be referred to a liver specialist. They will then likely have a liver biopsy to stage the disease more accurately
Management of Non-alcoholic Fatty Liver Disease
- the mainstay of treatment is lifestyle changes (particularly weight loss) and monitoring
- there is ongoing research into the role of gastric banding and insulin-sensitising drugs (e.g. metformin, pioglitazone)
Diagnosis of metabolic syndrome
3 out of 5:
- diabetes
- HTN
- hyperlipidaemia
- hypertriglyceridaemia
- obesity
What histopathological changes may be seen in hepatosteatosis
Mechanism of formation of Mallory-Denk bodies is unclear. But these are tangles in the cytoplasm
What happens, histologically, in chronic hepatosteatosis?
Stellate cells lay fibrotic tissue
What liver enzymes would be increased due to damage to hepatocytes?
- ALT (to a greater extent)
- AST
What liver enzymes will be increased due to the progression of NAFLD?
(progression from steatosis - steatohepatitis - fibrosis/cirrhosis)
- increase in ALT
- sometimes increase in AST
How would the picture of increased liver enzymes would look like in alcohol-induced liver disease?
- Increased AST
- AST:ALT ratio >2
What % of fat content in the liver is considered abnormal?
> 5%
Is NAFLD reversible?
- Steatosis and steatohepatitis -> potentially reversible if addressing the cause
- Fibrosis -> not reversible
Detailed (with values) criteria for metabolic syndrome
- blood pressure >130/85 mmHg
- serum HDL concentration <1.04 mmol/l in men and <1.29 mmol/l in women.
- serum TG concentration >1.69 mmol/l
- fasting plasma glucose >6.1 mmol/l
- abdominal obesity (waist circumference >102 cm in men and >88 cm in women).
Symptoms of NAFLD
•Often asymptomatic, incidental finding on LFTs
Symptoms are vague:
- fatigue
- chronic malaise
- disturbed sleep
- abdominal pain
Signs of NAFLD
*also consider PMH
- raised ALT and AST
- exclude other aetiology for liver disease
- USS evidence of fat accumulation
- raised BMI/ abdominal obesity.
- metabolic syndrome
- Check the patient’s record for BMI, glucose, HbA1c, BP, waist measurement.
What’s NASH?
NASH – necro-inflammation with fibrosis, and has the potential to develop to cirrhosis and hepatocellular carcinoma
Patient’s factors that may suggest occurrence of more severe NASH
- Age > 45 years
- BMI >30kg/m2
- T2DM
- Found on USS
*These cases may require further investigation and possible liver biopsy
