Non-alcoholic fatty liver disease in children — formative SAQs

SAQ 1 — The overweight child with a mildly raised ALT (20 marks, ~15 minutes)

An eleven-year-old boy is reviewed at a routine visit. His body mass index is on the ninety-second percentile. He drinks two sugar-sweetened cans of soft drink a day, plays no organised sport, and spends most evenings on a screen. His alanine aminotransferase is 34 units per litre; the laboratory reports its normal range as up to 55 units per litre. His father has type 2 diabetes. ^[1]

Questions

1. Give the most likely diagnosis and explain why the laboratory reference range may be misleading. (4 marks) ^[1]
2. State the NASPGHAN 2017 sex-specific upper limits of normal for alanine aminotransferase and the age at which screening should begin. (4 marks) ^[1]
3. Outline how you would confirm the diagnosis and the threshold for formal evaluation and referral. (4 marks) ^[6]
4. Describe your first-line management and the weight-loss target associated with histological improvement. (5 marks) ^[1]
5. Summarise the new nomenclature and why it matters. (3 marks) ^[4]

Model answer (must-hit)

1. The most likely diagnosis is paediatric fatty liver disease, now named metabolic dysfunction-associated steatotic liver disease, given the overweight body mass index, the central adiposity pattern, the insulin-resistance family history, and the sedentary high-sugar lifestyle. The laboratory reference range is misleading because it was derived from populations that included people with undiagnosed fatty liver disease and is far higher than the metabolically healthy ninety-fifth percentile, so a value that looks in-range to the laboratory is in fact abnormal by the NASPGHAN thresholds. ^[1]
2. The NASPGHAN 2017 upper limits of normal are 22 units per litre for girls and 26 units per litre for boys, and screening with alanine aminotransferase should begin between ages nine and eleven years for all children with obesity and for children with overweight who have additional cardiometabolic risk factors. ^[1]
3. Confirm the elevation is persistent by repeating the alanine aminotransferase, and pursue formal evaluation when it remains above twice the sex-specific upper limit of normal for more than three months, or exceeds 80 units per litre at any time. The evaluation excludes viral, autoimmune, Wilson, alpha-1-antitrypsin, drug and metabolic causes, confirms steatosis and stages fibrosis non-invasively with elastography, and refers to paediatric gastroenterology or hepatology. ^[6]
4. First-line management is family-based lifestyle change: a calorie-appropriate diet with a sharp reduction in sugar-sweetened beverages and fructose, increased fruit, vegetables and fibre, portion control, at least one hour of moderate to vigorous activity daily, and reduced sedentary screen time, engaging the whole household. A weight reduction of around 7 to 10 per cent is associated with histological improvement of steatohepatitis. ^[1]
5. The 2023 multisociety Delphi consensus renamed non-alcoholic fatty liver disease to metabolic dysfunction-associated steatotic liver disease and non-alcoholic steatohepatitis to metabolic dysfunction-associated steatohepatitis, defining the disease by steatosis plus at least one cardiometabolic criterion rather than by exclusion of alcohol. This matters because it ties the liver disease to the cardiometabolic risk it travels with and aligns paediatric and adult practice. ^[4]