How does sepsis cause jaundice?

The pathogenesis here is multifactorial, and so breaking it down systematically is probably best.

• Haemolysis - There are many ways by which sepsis can cause haemolysis of red blood cells. Otherwise normal red cells can be haemolysed directly by certain organisms (e.g. C. perfringens, or in malaria) or else they may cause an autoimmune haemolytic anaemia. Furthermore, the drugs used to treat sepsis may cause haemolysis by a number of mechanisms.  Lastly, any these processes are exacerbated by any underlying red cell abnormalities, the classic case being glucose-6-phosphate dehydrogenase deficiency.


• Hepatic dysfunction - This is the most important cause in the majority of cases. Largely as a result of inflammatory cytokines, a large variety of abnormalities of bilirubin processing occur.  These include decreased bilirubin uptake, deficient intrahepatic processing (due, amongst other things, to a combination of hepatic ischaemia and hepatocellular injury) and intrahepatic cholestasis. 


• Extrahepatic biliary obstruction - Ascending cholangitis is fairly rare but an immensely important cause of jaundice to exclude in the septic patient.  It classically presents with the triad of fever, jaundice and right upper quadrant pain and is due to infection of a blocked hepatic or common bile duct.  This can be due to a gallstone, for instance.

Apologies for the brevity of the explanations here.  The full picture is absolutely vast, and you can read about it here if you need more detailed explanations.