Fatty liver disease in severe obese patients:Diagnostic value of abdominal ultrasound

AIM:To evaluate the sensitivity and specificity of abdominal ultrasound (US) for the diagnosis of hepatic steatosis in severe obese subjects and its relation to histological grade of steatosis. METHODS: A consecutive series of obese patients, who underwent bariatric surgery from October 2004 to May 2005, was selected. Ultrasonography was performed in all patients as part of routine preoperative time and an intraoperative wedge biopsy was obtained at the beginning of the bariatric surgery. The US and histological findings of steatosis were compared, considering histology as the gold standard. RESULTS: The study included 105 patients. The mean age was 37.2 ± 10.6 years and 75.2% were female. The histological prevalence of steatosis was 89.5%. The sensitivity and specificity of US in the diagnosis of hepatic steatosis were, respectively, 64.9% (95% CI: 54.9-74.3) and 90.9% (95% CI: 57.1-99.5). The positive predictive value and negative predictive value were, respectively, 98.4% (95% CI: 90.2-99.9) and 23.3% (95% CI: 12.3-39.0). The presence of steatosis onUS was associated to advanced grades of steatosis on histology (P = 0.016). CONCLUSION: Preoperative abdominal US in our series has not shown to be an accurate method for the diagnosis of hepatic steatosis in severe obese patients. Until another non-invasive method demonstrates better sensitivity and specificity values, histological evaluation may be recommended to these patients undergoing bariatric surgery.

Nonalcoholic fatty liver disease in asymptomatic Brazilian adolescents

AIM： To evaluate the prevalence and clinical characteristics of Nonalcoholic fatty liver disease （NAFLD） among asymptomatic Brazilian adolescents. METHODS： Transversal observational study included asymptomatic adolescents with central obesity from private and public schools in Salvador-Bahia, northeastern Brazil. The children answered a questionnaire that in- cluded age, gender, race, and medical history, and were submitted to a complete physical exam and abdominal ultrasound. Biochemical exams included： ALT, AST, GGT, C reactive protein （CRP）, fasting glucose, insulin, cholesterol and triglycerides. Criteria for NAFLD included： the presence of steatosis in ultrasound and/or high level of ALT, negative or occasional historic of intake of alcohol （4 140 g/wk）, negative investigation for hepatitis A, B, C, auto-immune hepatitis, Wilson disease and hemochro-matosis.RESULTS： From October, 2005 to October, 2006, the study included 1801 subjects between 11 and 18 years of age and a mean age of 13.7± 2.0 years. One hun- dred ninety-nine had central obesity. The prevalence of NAFLD was 2.3%, most of whom were male and white. Insulin resistance （IR） was observed in 22.9% of them and had positive correlations with ALT and GGT （P 〈 0.05）. Elevated CRP was observed in 6.9% of the cases; however, it was not associated with WC, IR or liver enzymes. CONCLUSION： The prevalence of NAFLD in Brazilian adolescents was low. The ethnicity may have influence this frequency in the population studied, which had a large proportion of African descendents.