Diagnóstico de esteatosis hepática por métodos clínicos, bioquímicos y por imágenes / Diagnosis of hepatic steatosis using clinical, biochemical and imaging methods

La enfermedad hepática grasa no alcohólica comprende un espectro de afecciones hepáticas que va desde la simple esteatosis a la esteatohepatitis, fibrosis y hasta cirrosis. Su prevalencia aumenta con la edad, la obesidad y está fuertemente asociada con la presencia de síndrome metabólico y aumento de la mortalidad cardiovascular y por enfermedades malignas. Se produce por una acumulación de triglicéridos en los hepatocitos relacionada con insulinorresistencia hepática y muscular. Su presencia se asocia con aumento de transaminasa glutámico-oxaloacética o glutamico-pirúvica, aunque esta última puede no estar elevada en la enfermedad avanzada. Existen 5 índices utilizados para el diagnóstico de esteatosis hepática: SteatoTest, fatty liver index, NAFLD liver fat score, lipid acumulation product y hepatic steatosis index, mientras que para esteatohepatitis contamos con el NASH test, NASH diagnostics, NASH score y HAIR (Hypertention, increased ALT and IR o Insulin resistence). En estadios de fibrosis el índice transaminasa glutamicooxáloacetica-glutamicopiruvica aumenta, así como la ferritina en sangre y el valor del NAFLD fibrosis score, siendo de alta especificidad para el diagnóstico. La ecografía abdominal tiene una gran disponibilidad, pero su sensibilidad diagnóstica es menor cuando existen grados leves de infiltración grasa hepática. La tomografía computada tiene una especificidad del 100% cuando el contenido graso es mayor al 30% pero la radiación emitida no permite un uso frecuente. La resonancia magnética con espectroscopia constituye el método de elección para la detección y cuantificación de contenido de grasa hepática. La biopsia hepática es un método invasivo que permite una clasificación pronóstica adecuada de la enfermedad, pero por sus complicaciones solo debe realizarse en pacientes seleccionados: aquellos con riesgo elevado de esteatohepatitis o riesgo de fibrosis por laboratorio o clínica, o con otras enfermedades hepáticas coexistentes. La identificación temprana de enfermedad hepática grasa no alcohólica permite la implementación de medidas tempranas para disminuir la morbimortalidad asociada a esta condición.

Non-alcoholic fatty liver disease (NAFLD) includes a spectrum of liver diseases ranging from steatosis to steatohepatitis, fibrosis and cirrhosis. Its prevalence increases with age and with obesity, and is strongly associated with the presence of metabolic syndrome and increased cardiovascular and malignant diseases. It is caused by an accumulation of triglycerides in liver hepatocytes and muscles, and related to insulin resistance. Its presence is associated with the increase of alanine aminotransferase (alt), although it may not be elevated in advanced disease. There are 5 indexes used for the diagnosis of hepatic steatosis: SteatoTest, fatty liver index, NAFLD liver fat score, lipid accumulation product and hepatic steatosis index, whereas for esteatohepatitis the NASH test, NASH diagnostics, as well as the non-alcoholic steatohepatitis (NASH) score and HAIR (hypertension, ALT, and insulin resistance). In stages of fibrosis AST-ALT index increases as well as ferritin in blood and the NAFLD fibrosis score, which has a high specificity for diagnosis. Abdominal ultrasound is widely available, but its diagnostic sensitivity is lower when there are mild degrees of hepatic fatty infiltration. Computed tomography has a specificity of 100% when fat content is greater than 30%, but the radiation emitted prevents frequent use. Magnetic resonance spectroscopy is the method of choice for the detection and quantification of liver fat content. Liver biopsy is an invasive method that enables appropriate prognostic classification of the disease, but has some complications, and should only be performed in selected individuals: high risk of steatohepatitis or fibrosis risk of laboratory or clinical or other co-existing liver disease. Early identification of NAFLD allows early measures to be implemented in order to reduce morbidity and mortality associated with this condition.

Relationship between Controlled Attenuation Parameter and Hepatic Steatosis as Assessed by Ultrasound in Alcoholic or Nonalcoholic Fatty Liver Disease

BACKGROUND/AIMS: The aim of this study was to evaluate the relationship between controlled attenuation parameter (CAP) and hepatic steatosis, as assessed by ultrasound (US) in patients with alcoholic liver disease (ALD) or non-alcoholic fatty liver disease (NAFLD). METHODS: Patients with either ALD or NAFLD who were diagnosed with fatty liver with US and whose CAP scores were measured, were retrospectively enrolled in this study. The degree of hepatic steatosis assessed by US was categorized into mild (S1), moderate (S2), and severe (S3). RESULTS: A total of 186 patients were included: 106 with NAFLD and 80 with ALD. Regarding hepatic steatosis, the CAP score was significantly correlated with US (ρ=0.580, p<0.001), and there was no significant difference between the NAFLD and ALD groups (ρ=0.569, p<0.001; ρ=0.519, p<0.001; p=0.635). Using CAP, area under receiver operating characteristic curves for ≥S2 and ≥S3 steatosis were excellent (0.789 and 0.843, respectively). For sensitivity ≥90%, CAP cutoffs for the detection of ≥S2 and ≥S3 steastosis were separated with a gap of approximately 35 dB/m in all patients and in each of the NAFLD and ALD groups. CONCLUSIONS: The CAP score is well correlated with hepatic steatosis, as assessed by US, in both ALD and NAFLD.