nonalcoholic%20fatty%20liver%20disease
NONALCOHOLIC FATTY LIVER DISEASE

Nonalcoholic fatty liver disease is having excessive hepatic fat (in the form of triglycerides) accumulation not due to excessive alcohol consumption or other secondary causes.

It is considered as a hepatic manifestation of metabolic syndrome.

Progression of nonalcoholic fatty liver disease is variable.

Diagnosis

  • Patient with persistent abnormal liver enzymes, with insulin resistance and/or metabolic syndrome risk factors should be screened for nonalcoholic fatty liver disease (NAFLD)
  • Criteria for diagnosing NAFLD:
    • Presence of steatosis in either imaging or histology studies
    • Alcoholic liver disease has been ruled out (daily alcohol consumption did not exceed 30 g for males and 20 g for females)
    • Chronic use of steatogenic medications and other liver diseases (eg chronic hepatitis B/C, autoimmune liver disease) and metabolic or monogenic hereditary liver diseases have been ruled out

Classification

 Clinical Entities

  • Nonalcoholic fatty liver (NAFL)
    • Minimal risk of progression to cirrhosis and liver failure
  • Nonalcoholic steatohepatitis (NASH)
    • Can progress to cirrhosis, liver failure or even hepatocellular carcinoma



History

  • Patients are usually asymptomatic until the condition progresses to liver cirrhosis
  • Sometimes have vague symptoms of fatigue, malaise, and abdominal discomfort
  • Detailed patient history of alcohol consumption should be sought
  • Dietary and physical activity habits should be assessed because these influence the development and progression of NAFLD

Physical Examination

  • Physical findings to (rule out other causes of liver disease) assess progressive liver disease are presence of spider angiomas, ascites, hepatomegaly, splenomegaly, palmar erythema, jaundice, hepatic encephalopathy

Laboratory Tests

  • Shows mild elevation of transaminases (ALT, AST)
  • Levels of serum transaminases are helpful in screening for NAFLD but these do not identify severity of NAFLD
  • Hepatitis B surface antigen, hepatitis C virus antibody or HCV-RNA should be done to exclude viral hepatitis as the cause of the fatty liver findings without chronic alcohol intake
  • Other findings include elevated hyaluronic acid that indicates fibrosis and low platelet counts with evidence of liver dysfunction such as elevated serum bilirubin and ammonia indicative of cirrhosis
Liver Biopsy
  • Diagnostic procedure considered in patients who are at increased risk to have NASH and advanced fibrosis or are suspected of having coexisting chronic liver diseases where there is a need to distinguish NASH from other chronic liver diseases
  • Essential in diagnosing and staging NASH

Histology

  • NAFLD is characterized by macrovesicular steatosis in 5% of hepatocytes
    • Fibrosis is the most significant histological feature as it is related with long-term mortality
  • Histologically, NAFL is characterized by ≥5% hepatic steatosis with no evidence of hepatocellular injury (eg hepatocyte ballooning) or fibrosis
  • NASH is characterized histologically by ≥5% hepatic steatosis associated with evidence of liver cell injury (eg ballooning degeneration) and lobular inflammation, with or without fibrosis

Imaging

  • Used to detect fatty changes
  • Abdominal ultrasound is the most common method of assessing hepatic steatosis
    • Preferred diagnostic procedure for NAFLD as it provides additional hepatobiliary information aside from presence of steatosis
  • Computed tomography and magnetic resonance imaging (MRI) seem to be more objective and more sensitive techniques for the quantification of steatosis, but MRI is still less widely available and much more expensive

Screening For Alcohol Abuse or Dependency

  • Patient’s alcohol consumption should be established to diagnose NAFLD
    • Threshold is <20 g/day in females and <30 g/day in males or
    • A standard alcoholic drink (ie 14 g of pure alcohol) consumed on average per week of >14 drinks in females and >21 drinks in males
  • To evaluate the alcohol consumption of the patient, appropriate specialized questionnaires or scoring systems should be used
  • Tool most often used to assess alcohol dependency is “CAGE” questionnaire which refers to lifetime occurrence of the following:
    • Cutting down on drinking
    • Annoyance at others’ concerns about drinking
    • Feeling Guilty about drinking
    • Use of alcohol as an Eye opener in the morning
  • CAGE confirms clinically relevant alcohol consumption if at least one of the above questions is answered positively and if the Alcohol Use Disorders Identification Test (AUDIT) score is higher than 8
  • Other screening tools include the Michigan Alcoholism Screening Test (MAST) and the Lifetime Drinking History

Evaluation of Steatosis

Validated Steatosis Scores
  • Used in large-scale screening for presence of steatosis
  • NAFLD fibrosis score is a widely validated scoring system for predicting the severity of fibrosis
    • It is based on 6 readily assessable clinical variables that include age, body mass index (BMI), hyperglycemia, platelet count, albumin and the aspartate transaminase/alanine transaminase ratio that is calculated using a published formula
  • Enhanced liver fibrosis (ELF) test is used to determine the presence of liver fibrosis
    • ELF score of ≥10.51 with NAFLD indicates advanced liver fibrosis
    • Can also be used to test if pharmacological therapy is effective
  • Other scoring systems are Fatty Liver Index (FLI), SteatoTest and NAFLD liver fat score
Digital Edition
Asia's trusted medical magazine for healthcare professionals. Get your MIMS Gastroenterology - Malaysia digital copy today!
Sign In To Download
Editor's Recommendations
Most Read Articles
2 days ago
The types of bariatric surgery differentially affect the risk of developing acute pancreatitis postoperatively, such that the risk is greater in patients who undergo vertical sleeve gastrectomy vs Roux-en-Y gastric bypass surgery, according to a study. Risk factors include younger age and presence of gallstones.
6 days ago
Elderly adults using hypoglycaemic glucose-lowering drugs, such as insulin and glinides, have an excess risk of hospitalization for serious trauma, a recent study has found.
6 days ago
Rather than the presence or type or urinary incontinence, increasing severity of urinary incontinence correlates with increased depression, anxiety and stress among treatment-seeking women with lower urinary tract symptoms (LUTS), suggests a study.
Roshini Claire Anthony, 4 days ago

Overweight or obese patients taking lorcaserin as an appetite suppressant may have the added benefit of a reduced risk of incident diabetes, according to results of the CAMELLIA-TIMI 61* trial presented at EASD 2018.