Porphyria Disorders
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Questions and Answers

What is the primary characteristic of acute hepatic porphyrias?

  • Deficiency in X-linked ALAS2
  • Photosensitivity without gastrointestinal symptoms
  • Increased synthesis of heme
  • Accumulation of ALA and PBG (correct)

    • Which of the following is NOT a symptom of acute hepatic porphyrias?

  • Abdominal pain
  • Delirium
  • Rash (correct)
  • Anxiety

    • What is the effect of using drugs such as barbiturates and ethanol in patients with acute hepatic porphyrias?

  • It increases the synthesis of heme
  • It induces the synthesis of the heme-containing CYP microsomal drug-oxidation system (correct)
  • It decreases the synthesis of ALAS1
  • It has no effect on heme synthesis

    • What is the result of deficiencies in ALAS1?

    <p>Unknown</p> Signup and view all the answers

    What is the characteristic of urine from a patient with porphyria cutanea tarda?

    <p>It is darker than normal</p> Signup and view all the answers

    What is the effect of increased synthesis of ALAS1?

    <p>Decreased synthesis of heme</p> Signup and view all the answers

    Which of the following porphyrias is characterized by abdominal pain and neuropsychiatric disturbances?

    <p>Acute intermittent porphyria</p> Signup and view all the answers

    What is the outcome of deficiencies in X-linked ALAS2?

    <p>Anemia</p> Signup and view all the answers

    What is a common feature of the hepatic porphyrias?

    <p>Decreased synthesis of heme</p> Signup and view all the answers

    What is the result of decreased heme synthesis in the liver?

    <p>Increased synthesis of ALAS1</p> Signup and view all the answers

    What is the primary source of heme destined for degradation?

    <p>Senescent RBC</p> Signup and view all the answers

    What is the effect of increased δ-aminolevulinic acid synthase activity?

    <p>Increased synthesis of intermediates</p> Signup and view all the answers

    What is the purpose of phlebotomy in the treatment of porphyrias?

    <p>To remove porphyrins</p> Signup and view all the answers

    What is the role of β-carotene in the treatment of porphyrias?

    <p>Scavenging free radicals</p> Signup and view all the answers

    What is the function of heme in the liver?

    <p>Repressor of the ALAS1 gene</p> Signup and view all the answers

    What is the purpose of intravenous injection of hemin and glucose in acute porphyria attacks?

    <p>To decrease ALAS1 synthesis</p> Signup and view all the answers

    What is the normal production of bilirubin per day?

    <p>300 mg</p> Signup and view all the answers

    What is the result of extensive hemolysis in patients with sickle cell anemia?

    <p>Elevated UCB levels in the blood</p> Signup and view all the answers

    What is the effect of hepatic damage on the enterohepatic circulation of urobilinogen?

    <p>It decreases the circulation of urobilinogen</p> Signup and view all the answers

    What is the consequence of hemolytic jaundice on the amount of urobilinogen entering the enterohepatic circulation?

    <p>It is increased</p> Signup and view all the answers

    What is the consequence of hepatocellular jaundice on the urinary excretion of urobilinogen?

    <p>It is increased</p> Signup and view all the answers

    What is the normal capacity of the liver to conjugate and excrete bilirubin per day?

    <p>3,000 mg</p> Signup and view all the answers

    What is the result of defects in the metabolism of bilirubin at more than one step?

    <p>Accumulation of unconjugated bilirubin</p> Signup and view all the answers

    What is the consequence of hemolysis on the production of conjugated bilirubin?

    <p>It is increased</p> Signup and view all the answers

    What is the likely cause of jaundice in obstructive jaundice?

    <p>Obstruction of the common bile duct</p> Signup and view all the answers

    What is the color of urine in conjugated hyperbilirubinemia?

    <p>Dark brown</p> Signup and view all the answers

    What is the term for the leakage of conjugated bilirubin into the blood?

    <p>Regurgitation</p> Signup and view all the answers

    What percentage of full-term newborn infants experience a rise in unconjugated bilirubin in the first postnatal week?

    <p>60%</p> Signup and view all the answers

    What is the term for the blockage of the common bile duct?

    <p>Extrahepatic cholestasis</p> Signup and view all the answers

    What is the likely cause of darkening urine in patients with jaundice?

    <p>Excretion of conjugated bilirubin in the urine</p> Signup and view all the answers

    What is the characteristic of stools in patients with obstructive jaundice?

    <p>Pale, clay color</p> Signup and view all the answers

    What is the term for the condition where conjugated bilirubin is not efficiently secreted from the liver into bile?

    <p>Intrahepatic cholestasis</p> Signup and view all the answers

    What is the outcome of decarboxylating DOPA in a reaction requiring PLP?

    <p>Formation of dopamine</p> Signup and view all the answers

    What is required for the hydroxylation of dopamine to form NE?

    <p>Ascorbic acid and copper</p> Signup and view all the answers

    What is the role of S-adenosylmethionine in catecholamine synthesis?

    <p>Methyl donor for N-methylation reactions</p> Signup and view all the answers

    What is the primary treatment for Parkinson disease?

    <p>Administration of L-DOPA</p> Signup and view all the answers

    What is the purpose of the blood-brain barrier?

    <p>To prevent dopamine from crossing into the brain</p> Signup and view all the answers

    What is the function of monoamine oxidase (MAO) in catecholamine degradation?

    <p>To oxidatively deaminate catecholamines</p> Signup and view all the answers

    What is the product of the MAO reaction that is excreted in the urine?

    <p>Vanillylmandelic acid</p> Signup and view all the answers

    What is the role of catechol-O-methyltransferase (COMT) in catecholamine degradation?

    <p>To O-methylate catecholamines</p> Signup and view all the answers

    What is the purpose of the reactions catalyzed by MAO and COMT?

    <p>To inactivate catecholamines</p> Signup and view all the answers

    What is the characteristic of catechols?

    <p>Having two adjacent hydroxyl groups</p> Signup and view all the answers

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