Editing Jaundice (section)

== Causes ==
[[File:Jaundice-types.png|thumb|upright=1.6|Types of jaundice]]
Jaundice is a sign indicating the presence of an underlying diseases involving abnormal bilirubin metabolism, liver dysfunction, or biliary-tract obstruction. In general, jaundice is present when blood levels of bilirubin exceed 3&nbsp;mg/dl.<ref name="Reuben_2012">{{cite book | vauthors = Reuben A |chapter=Jaundice |date=2012|title=Textbook of Clinical Gastroenterology and Hepatology|pages=84–92|publisher=John Wiley & Sons, Ltd|language=en|doi=10.1002/9781118321386.ch15|isbn=978-1-118-32138-6}}</ref> Jaundice is classified into three categories, depending on which part of the physiological mechanism the pathology affects. The three categories are:

{| class="wikitable mw-collapsible"
|-
!Category
!Definition
|-
|Prehepatic/hemolytic
|The pathology occurs prior to the liver metabolism, due to either intrinsic causes to red blood cell rupture or extrinsic causes to red blood cell rupture.
|-
|Hepatic/hepatocellular
|The pathology is due to damage of parenchymal liver cells.
|-
|Posthepatic/cholestatic
|The pathology occurs after bilirubin conjugation in the liver, due to obstruction of the biliary tract and/or decreased bilirubin excretion.{{cn|date=April 2024}}
|}

=== Prehepatic causes ===
Prehepatic jaundice is most commonly caused by a pathological increased rate of red blood cell (erythrocyte) [[hemolysis]]. The increased breakdown of erythrocytes → increased unconjugated serum bilirubin → increased deposition of unconjugated bilirubin into mucosal tissue.<ref>{{cite book | vauthors = Joseph A, Samant H | chapter = Jaundice |date=2022 | chapter-url = http://www.ncbi.nlm.nih.gov/books/NBK544252/ | title = StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=31334972 |access-date=2022-04-23 }}</ref> These diseases may cause jaundice due to increased erythrocyte hemolysis:<ref>{{cite web |title=What causes jaundice in hemolytic anemia? |url=https://www.medscape.com/answers/201066-27045/what-causes-jaundice-in-hemolytic-anemia |access-date=2022-04-26 |website=www.medscape.com |language=en}}</ref>
* [[Sickle-cell anemia]]<ref>{{cite web|title=What Is Sickle Cell Disease?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/sca|website=National Heart, Lung, and Blood Institute|access-date=8 March 2016|date=12 June 2015|url-status=live|archive-url=https://web.archive.org/web/20160306021706/http://www.nhlbi.nih.gov/health/health-topics/topics/sca/|archive-date=6 March 2016}}</ref>
* [[Spherocytosis]]<ref>{{cite book| vauthors = Hillman RS, Ault KA, Rinder HM |title=Hematology in clinical practice: a guide to diagnosis and management|url=https://books.google.com/books?id=NJs1VpA8SEoC&pg=PA146|accessdate=15 November 2010|year=2005|publisher=McGraw-Hill Professional|isbn=978-0-07-144035-6|pages=146–}}</ref>
* [[Thalassemia]]<ref>{{cite web |url=https://www.lecturio.com/concepts/thalassemia/ | title= Thalassemia
|website=The Lecturio Medical Concept Library |access-date= 27 July 2021}}</ref>
* [[Pyruvate kinase deficiency]]
* [[Glucose-6-phosphate dehydrogenase deficiency]]
* [[Microangiopathic hemolytic anemia]]
* [[Hemolytic–uremic syndrome]]
* Severe [[malaria]] (in endemic countries)

=== Hepatic causes ===
[[File:Bilirubin pigment in cholestatic liver 40X.jpg|thumbnail|Microscopy of a biopsy of a cholestatic liver showing bilirubin pigment (brown pigment), [[H&E]] stain]]
Hepatic jaundice is caused by abnormal liver metabolism of bilirubin.<ref>{{cite book | vauthors = Kalakonda A, Jenkins BA, John S | chapter = Physiology, Bilirubin |date=2022 |url= http://www.ncbi.nlm.nih.gov/books/NBK470290/ | title = StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=29261920 |access-date=2022-04-23 }}</ref> The major causes of hepatic jaundice are significant damage to hepatocytes due to infectious, drug/medication-induced, autoimmune etiology, or less commonly, due to inheritable genetic diseases.<ref>{{cite book | vauthors = Tripathi N, Jialal I | chapter = Conjugated Hyperbilirubinemia |date=2022 | chapter-url=http://www.ncbi.nlm.nih.gov/books/NBK562172/ | title = StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=32965843 |access-date=2022-04-23 }}</ref> The following is a partial list of hepatic causes to jaundice:<ref>{{cite book | vauthors = Tholey D | chapter = Jaundice |date=January 2023 |url= https://www.merckmanuals.com/professional/hepatic-and-biliary-disorders/approach-to-the-patient-with-liver-disease/jaundice | title = Merck Manual. Professional Version |publisher=Merck|access-date=2022-04-12}}</ref>
* [[Acute hepatitis]]
* [[Chronic hepatitis]]
* [[Hepatotoxicity]]
* [[Cirrhosis]]
* [[Drug-induced hepatitis]]
* [[Alcoholic liver disease]]
* [[Gilbert's syndrome]] (found in about 5% of the population, results in induced mild jaundice)
* [[Crigler–Najjar syndrome, type I]]
* [[Crigler–Najjar syndrome, type II]]
* [[Leptospirosis]]

===Posthepatic causes (Obstructive jaundice)===
Posthepatic jaundice (obstructive jaundice) is caused by a blockage of bile ducts that transport bile containing conjugated bilirubin out of the liver for excretion.{{fact|date=March 2025}} This is a list of conditions that can cause posthepatic jaundice:
* [[Common bile duct stone|Choledocholithiasis]] (common bile duct gallstones). It is the most common cause of obstructive jaundice.
* [[Pancreatic cancer]] of the pancreatic head
* Biliary tract strictures
* [[Biliary atresia]]
* [[Primary biliary cholangitis]]
* [[Cholestasis of pregnancy]]
* [[Acute pancreatitis|Acute Pancreatitis]]
* [[Chronic pancreatitis|Chronic Pancreatitis]]
* [[Pancreatic pseudocyst]]s
* [[Mirizzi's syndrome]]
* Parasites ("[[liver fluke]]s" of the [[Opisthorchiidae]] and [[Fasciolidae]])<ref>{{cite web|date=2019-04-18|title=CDC – Liver Flukes|url=https://www.cdc.gov/parasites/liver_flukes/index.html|access-date=2020-06-05|website=www.cdc.gov|language=en-us}}</ref>