Gastroenterology Book

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BilirubinAka: Total Bilirubin, Serum Bilirubin, Hyperbilirubinemia

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  1. See Also
    1. Jaundice
    2. Direct Bilirubin (Conjugated Bilirubin)
    3. Indirect Bilirubin (Unconjugated Bilirubin)
    4. Neonatal Bilirubin
    5. Liver Function Test
    6. Liver Function Test Abnormality
  2. Physiology
    1. Heme product degradation yields Hemoglobin
      1. Red Blood Cells (responsible for 80% of heme product)
      2. Myoglobin
      3. Maturing Red Blood Cells
    2. Hemoglobin transported to reticuloendothelial system
      1. Hemoglobin bound to Haptoglobin in plasma
      2. Hemoglobin metabolized in reticuloendothelial system
        1. Heme is oxidized to bilverdin
        2. Iron
        3. Globin
    3. Bilverdin converted to Unconjugated Bilirubin
      1. Normal production of bilirubin: 4 mg/kg/day
    4. Unconjugated Bilirubin circulates
      1. Tightly bound to albumin and fat soluble
        1. Displaced bilirubin causes
          1. Albumin saturated with bilirubin or
          2. Medications (e.g. Sulfisoxazole, Streptomycin, Vitamin K)
        2. Displaced Unconjugated Bilirubin crosses blood-brain barrier and placenta
          1. Results in toxicity (e.g. Hepatic Encephalopathy, Kernicterus)
      2. Unconjugated Bilirubin is insoluble in water
        1. Not found in tears or Saliva
        2. Unconjugated Bilirubin can not be excreted
      3. Concentrates in high albumin containing tissues
        1. Skin (especially face and trunk): Jaundice
        2. Sclera: Scleral Icterus
    5. Unconjugated Bilirubin converts to Conjugated Bilirubin
      1. Bilirubin conjugated with glucuronic acid in liver
        1. Conjugated by glucuronosyltransferase enzyme
      2. Conjugated Bilirubin is water soluble
      3. Only Conjugated Bilirubin can be excreted
    6. Conjugated Bilirubin excreted into biliary tract
      1. Stored in gallbladder
      2. Ultimately excreted into duodenum
    7. Conjugated Bilirubin passes into feces
      1. Converted by bacterial enzymes to Urobilinogen
      2. Most Urobilinogen excreted in stool
      3. Small levels Urobilinogen reabsorbed and urinated
  3. Normal
    1. Total Bilirubin <1.0 mg/dl
  4. Increased Total Bilirubin
    1. Diagnosis depends on whether bilirubin is conjugated
      1. See Unconjugated Bilirubin (Hemolytic Jaundice)
      2. See Conjugated Bilirubin (Obstructive Jaundice)
    2. General Hyperbilirubinemia Causes
      1. See Medication Causes of Jaundice
      2. Hemolysis
      3. Liver disease
        1. Hepatitis
        2. Cirrhosis
        3. Liver tumor
        4. Cholangitis
        5. Biliary Tract Obstruction
        6. Epstein Barr Virus (EBV)
        7. Cytomegalovirus (CMV)
        8. Hereditary
          1. Gilbert's disease
          2. Dubin-Johnson syndrome
        9. Congestive Heart Failure
          1. Hepatic congestion
      4. Pulmonary Causes
        1. Pulmonary infarction
        2. Pulmonary Embolus

Bilirubin (C0005437)

Definition (MSH)A bile pigment that is a degradation product of HEME.
Definition (CSP)bile pigment that is a degradation product of heme.
Definition (NCI)(bil-ih-ROO-bun) Substance formed when red blood cells are broken down. Bilirubin is part of the bile, which is made in the liver and is stored in the gallbladder. The abnormal buildup of bilirubin causes jaundice.
ConceptsOrganic Chemical (T109) , Biologically Active Substance (T123)
EnglishBilirubin, Bilirubin IX alpha, BILIRUBIN PREPARATION, Conjugated and unconjugated bilirubin, Total bilirubin
Spanishbilirrubina
CreditsDerived from the NIH UMLS (Unified Medical Language System)


Hyperbilirubinemia (C0020433)

Definition (MSH)A condition characterized by an abnormal increase of BILIRUBIN in the blood, which may result in JAUNDICE. Bilirubin, a breakdown product of HEME, is normally excreted in the BILE or further catabolized before excretion in the urine.
Definition (CSP)pathologic process consisting of an abnormal increase in the amount of bilirubin in the circulating blood, which may result in jaundice.
ConceptsDisease or Syndrome (T047)
EnglishBILIRUBINAEMIA, Bilirubinemia, Bilirubinemias, Hyperbilirubinaemia, Hyperbilirubinemia, Hyperbilirubinemias
Spanishbilirrubinemia, hiperbilirrubinemia
CreditsDerived from the NIH UMLS (Unified Medical Language System)


Bilirubin, total measurement (C0201913)

Definition (NCI)A measurement of the total bilirubin in a biological specimen.
Definition (NCI)Bilirubin is a breakdown product of hemoglobin. Total and direct bilirubin are usually measured to screen for or to monitor liver or gall bladder dysfunction. (from MedlinePlus Medical Encyclopedia)
ConceptsLaboratory Procedure (T059)
EnglishBILI, Bilirubin, Total bilirubin, Total bilirubin level
Spanishbilirrubina total, medición total de bilirrubina, medicion total de bilirrubina
CreditsDerived from the NIH UMLS (Unified Medical Language System)



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