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Download MLAB 2401: Clinical Chemistry Keri Brophy
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MLAB 2401: Clinical Chemistry Keri Brophy-Martinez Alterations in Liver Function Jaundice/Icterus • Yellow discoloration of the skin, eyes and mucous membranes • Due to the presence of bilirubin • Onset seen at bilirubin levels > 3.0 mg/dL • Kernicterus – Yellow staining of the meninges of the brain due to bilirubin – Found in newborns – Causes brain damage Classification of Jaundice • Prehepatic • Hepatic • Posthepatic Classifications of Jaundice • Prehepatic – Abnormality is outside the liver – Liver function is normal – Cause: too much bilirubin presented to liver – Result • Increase in unconjugated bilirubin • Total bilirubin: increased or normal • Increase in serum iron – Examples: acute /chronic hemolytic anemias Classifications of Jaundice • Hepatic – Intrinsic liver disease or defect – Caused by • Disorders of bilirubin conjugation • Disorders of bilirubin transport • Hepatocellular injury or destruction – Cirrhosis – Tumors – Infection – Toxins – Intrahepatic obstructions Inherited Hyperbilirubinemias Liver • Gilbert Syndrome Reduction in the activity of UDP-glucoronyl transferase • Crigler-Najjar syndrome Defective UDPG-transferase • Dublin-Johnson disease Post-conjugation failure Acquired Hyperbilirubinemias • Neonatal jaundice – Deficiency of glucuronyl transferase – Causes an increase in unconjugated bilirubin – Leads to kernicterus – Treat by exposure to UV light or exchange transfusion Classifications of Jaundice • Posthepatic – Abnormality is outside the liver – Liver function is normal – Biliary obstruction due to gallstones, tumors, edema – Stool turns clay-colored due to lack of bile – Results: • Increased: Conjugated bilirubin, urinary bilirubin, ALP, GGT, total bilirubin, unconjugated bilirubin • Decreased: Urine and fecal urobilinogen Other Liver Dysfunctions • • • • Reye’s Syndrome Cirrhosis Drug & Alcohol Disorders Hepatitis Reye Syndrome • Group of disorders caused by infectious, metabolic, toxic or drug-induced disease found mostly in children • Often preceded by viral syndrome • Related to aspirin consumption during the viral syndrome • Symptoms – Profuse vomiting – Neurological impairment Cirrhosis • Scar tissue replaces normal healthy liver tissue • As time moves forward, function deteriorates and signs appear – Fatigue, nausea, weight loss, jaundice, etc • Common causes – Chronic alcoholism – Hepatitis • Results: – Increased: unconjugated and conjugated bilirubin, ALP, GGT,AST, ALT – Decreased: cholesterol, albumin Drug and Alcohol Disorders • Accounts for 1/3 to ½ of acute liver failure since the liver plays a major role in drug metabolism • Drugs cause an immune mediated injury to the hepatocytes, resulting in disease • Ethanol is the most significant • Acetaminophen also common • Several stages of classification based on disease severity Alcoholic Liver Disease (ALD) • Breakdown of alcohol leads to toxin formation • Risk factors for ALD include: – History and magnitude of alcohol consumption – Hepatitis B or C infection – Gender – Genetic factors – Nutritional status Alcoholic Injury • Stages – Alcoholic Fatty Liver • Mildest form • Elevations of AST, ALT, GGT • Complete recovery possible if drug removed – Alcoholic hepatitis • Moderate elevations of AST, ALT, GGT • Bilirubin, ALP also elevated • Albumin decreased • PT prolonged – Alcoholic cirrhosis • Elevated AST, ALT, GGT, ALP, total bilirubin • Albumin decreased • PT prolonged Hepatitis • Inflammation of the liver • Viral, bacterial, radiation, drugs, chemicals and others can cause inflammation • Viral infections account for the majority of cases in the clinical lab • Includes subtypes A, B,C, D, and E • Clinical Symptoms – Jaundice, dark urine, fatigue, nausea, abdominal pain Hepatitis Viruses Virus Incubation Period Mode of transmission Vaccine Chronic Infection Hepatitis A 2-6 weeks Fecal-oral Yes NO Hepatitis B 8-26 weeks Parenteral, sexual Yes Yes Hepatitis C 2-15 weeks Parenteral, sexual No Yes Hepatitis D 21-90 days Parenteral, sexual Yes Yes Hepatitis E 3-6 weeks Fecal-oral No ? References • Bishop, M., Fody, E., & Schoeff, l. (2010). Clinical Chemistry: Techniques, principles, Correlations. Baltimore: Wolters Kluwer Lippincott Williams & Wilkins. • http://kidshealth.org/parent/pregnancy_center/newborn_car e/jaundice.html • Sunheimer, R., & Graves, L. (2010). Clinical Laboratory Chemistry. Upper Saddle River: Pearson .
