MLAB 2401: Clinical Chemistry Keri Brophy-Martinez

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MLAB 2401 Clinical ChemistryKeri Brophy-Martinez

• Alterations in Liver Function

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Jaundice/Icterus

• Yellow discoloration of the skin, eyes and mucous
  membranes
• Due to the presence of bilirubin
• Onset seen at bilirubin levels gt 3.0 mg/dL
• Kernicterus
• Yellow staining of the meninges of the brain due
  to bilirubin
• Found in newborns
• Causes brain damage

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Classification of Jaundice

• Prehepatic
• Hepatic
• Posthepatic

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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

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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

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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

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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

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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

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Other Liver Dysfunctions

• Reyes Syndrome
• Cirrhosis
• Drug Alcohol Disorders
• Hepatitis

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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

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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

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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

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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

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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

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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

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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 ?
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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/newb
  orn_care/jaundice.html
• Sunheimer, R., Graves, L. (2010). Clinical
  Laboratory Chemistry. Upper Saddle River Pearson
  .