Fatty Liver Disease
Excess fat accumulation in liver cells, regardless of cause. Covers the spectrum from simple steatosis to non-alcoholic steatohepatitis (NASH) and alcoholic liver disease — the most common chronic liver pathology worldwide.
What it is
Fatty liver disease — increasingly called metabolic dysfunction-associated steatotic liver disease (MASLD) or simply steatotic liver disease (SLD) under the 2023 nomenclature — describes pathological fat accumulation in hepatocytes (>5% of liver cells). The category subsumes NAFLD (non-alcoholic, driven by metabolic syndrome), alcoholic fatty liver disease (heavy alcohol use, AST/ALT ratio typically >2), and combined metabolic-and-alcoholic disease (MetALD). Most patients have simple steatosis with no progression, but a meaningful minority develop steatohepatitis (NASH) with inflammation, fibrosis, cirrhosis, and rarely hepatocellular carcinoma. The condition is a leading cause of liver transplantation in many countries.
Key lab markers
- ALT — typically the first to rise; AST often elevated too.
- AST/ALT ratio — usually <1 in non-alcoholic disease; >2 suggests alcoholic component.
- GGT — often elevated, particularly in alcohol-related disease.
- Triglycerides, HDL, fasting glucose, HbA1c — the metabolic-syndrome cluster.
- FIB-4 score — non-invasive fibrosis stratification (uses age, AST, ALT, platelets).
- Liver ultrasound, transient elastography (FibroScan) — confirm steatosis and quantify fibrosis without biopsy.
Symptoms
Most patients are asymptomatic — fatty liver is typically caught incidentally on lab work or imaging. Late-stage disease may present with:
- Right-upper-quadrant discomfort
- Fatigue
- Hepatomegaly
- Signs of advanced liver disease: jaundice, ascites, varices, hepatic encephalopathy in cirrhotic patients
When to discuss with a doctor
Persistent ALT elevation in a patient with overweight, type 2 diabetes, dyslipidaemia or alcohol use warrants a primary-care work-up: viral hepatitis serology, ultrasound, FIB-4 calculation, alcohol-use history. Significant fibrosis (FIB-4 >2.67 or transient elastography >8 kPa) needs hepatology referral. The cornerstone of treatment is 7–10% weight loss for metabolic-driven disease — this reverses steatosis and improves fibrosis. Alcohol abstinence is critical for any alcoholic component. Pharmacotherapy is evolving — resmetirom recently received FDA approval for NASH with significant fibrosis. Mediora.AI flags the liver pattern alongside the metabolic and alcohol context.