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biliary cast formation almost always occurs in orthotopically transplanted livers as a consequence of complications .
however , in the past few years , gastroenterologists in germany have observed and reported on an unusual sclerosing cholangitis in patients who have recovered from life - threatening disease in intensive care units ( icus ) .
this newly described entity has been named sclerosing cholangitis in critically ill patients ( sc - cip ) ( 1 - 4 ) .
this new disorder is unfamiliar to many radiologists , and no reports focusing on the radiological findings associated with biliary cast formation in sc - cip have been published .
we report a case of biliary cast formation with sc - cip and describe the computed tomography ( ct ) , magnetic resonance cholangiopancreatography ( mrcp ) , and endoscopic retrograde cholangiography ( erc ) findings .
a 68-year - old man was transferred to our hospital for further evaluation of cryptogenic organizing pneumonia ( cop ) .
he had a six - week history of intermittent chills , myalgia , general weakness , and dyspnea .
a contrast - enhanced chest ct acquired at a local medical center was reviewed by the chest radiologist at our hospital , whose first impression was also cop .
histologic confirmation was obtained by wedge resection via video - assisted thoracoscopic surgery ( vats ) .
the patient received aggressive icu treatment for cop with acute respiratory distress syndrome ( ards ) , including positive end expiratory pressures ( peep ) mode mechanical ventilation .
the patient did not have hypotension severe enough to require administering vasopressors , such as epinephrine or norepinephrine .
three weeks later , blood tests in the icu revealed elevated alanine transaminase ( alt , 126 u / l ) and alkaline phosphatase ( alp , 463 iu / l ) levels but a normal total bilirubin level .
the patient did not have any past medical history of hepatobiliary disease ; therefore , the clinician suspected drug - induced hepatitis .
the patient underwent abdominal ultrasound to exclude obstructive bile duct pathology or underlying chronic liver disease .
an abdominal ultrasound revealed a slightly coarse parenchymal echotexture in the liver and a sludge ball in the gallbladder .
there was no evidence of intrahepatic bile duct ( ihd ) or common bile duct ( cbd ) dilatation .
two weeks later , a contrast - enhanced abdominal ct was performed , due to increased alp elevation , and a total bilirubin level of 4.39 mg / dl was observed .
the contrast - enhanced abdominal ct showed suspicious multifocal strictures and irregularities in both ihds and diffuse mild wall thickening with increased intraluminal attenuation in the right main ihd , which can be misinterpreted as a partial volume averaging effect ( fig .
there was no evidence of thrombus formation or stenosis in the hepatic artery , portal vein , or hepatic vein .
we also considered immunoglobulin g4-related sclerosing disease because combined interstitial pneumonia and sclerosing cholangitis can appear in that disorder .
however , manifestation of igg4-related sclerosing disease as sclerosing cholangitis without autoimmune pancreatitis is unusual , and igg and igg4 levels were normal .
mrcp was performed for further evaluation of the suspicious increased intraluminal attenuation in the right main ihd , which was needed for the erc - assisted procedure by some possibility , and for the diagnosis of sclerosing cholangitis .
the mrcp showed multiple strictures , irregularity , and a beaded appearance in both ihds .
there was an elongated intraluminal filling defect in both central ihds that extended to the proximal cbd , which was suggestive of biliary casts in sclerosing cholangitis ( fig .
the erc revealed a diffuse , amorphous , elongated filling defect in both the central ihd and proximal cbd .
a black - pigmented biliary cast was retrieved through the ampullar of vater by basket ( fig .
further blood tests revealed improvements in the obstructive jaundice after the procedure , and the patient was discharged from the hospital after having received aggressive treatment including mechanical ventilation , for a total of six weeks .
one month later , a follow - up blood test administered on an outpatient basis again revealed an elevated total bilirubin level ( 8.60 mg / dl ) .
the newly appeared biliary casts in both the ihds and cbd were seen on mrcp , and the biliary casts were retrieved by basket on erc . however , biliary casts were also noted from the central to the peripheral ihds , and these casts could not be completely removed by basket ( fig .
a contrast - enhanced abdominal ct performed 6 months later found clearer indications of multiple irregular strictures and dilatations in both ihds ( fig .
biliary cast formation almost always occurs in orthotopically transplanted livers and is associated with ischemic injury to the biliary epithelium .
it occurs in 3% to 18% of orthotopic liver transplantations and results in biliary obstruction with infection and secondary hepatocyte and bile duct damage ( 5 ) .
it has been suggested that multiple etiological factors , such as biliary infection , bile duct damage , ischemia , fasting , and hemolysis , play roles in cast formation ( 5 ) .
biliary cast formation in non - transplanted livers is rare , and there are a limited number of case reports of patients who had emergent cholecystectomy or antiphospholipid antibody syndrome ( 6 ) . in our opinion , all of these previous cases may now be seen to have been sc - cip , considering the clinical histories and imaging findings .
sc - cip is a recently described entity that occurs as a long - term complication in icu patients during or after recovery from life - threatening illness .
it is characterized by persistent , progressive cholestasis and findings of sclerosing cholangitis on cholangiography ( 1 , 3 , 4 ) . the pathogenesis of sc - cip is still under discussion .
the most accepted pathogenesis involves arterial hypoperfusion of the perivascular plexus , and leads to ischemic injury of the bile duct epithelium , which is exclusively supplied by the perivascular plexus ; biliary cast formation and subsequent biliary infection follow ( 1 , 3 , 7 , 8) .
accordingly , many sc - cip cases require mechanical ventilation with high peep mode for severe respiratory problems or a high dose of vasoconstrictors , which can disturb the patient 's hepatosplanchnic hemodynamics .
clinical signs during the initial phases of sc - cip are not specific and are similar to those of endotoxin - associated jaundice .
sc - cip usually begins with rapidly increasing serum levels of alp and gamma - glutamyl transferase ( ggt ) , as well as elevated serum bilirubin levels .
however , the degree of bilirubin elevation is often less pronounced than that of alp and ggt ( 1 , 7 ) . despite apparent recovery from the primary illness , persistent cholestasis
is observed , and this is the main clinical finding that discriminates sc - cip from other types of cholestasis ( 7 ) .
jaeger et al . ( 4 ) have reported that the initial cholestasis is noted at a median of 6.5 days ( with a range of 4 - 11 days ) after the initial injury , and gelbmann et al .
( 1 ) have reported that elevated alp and ggt levels are observed at a mean of 9.4  6.1 days ( with a range of 4 - 31 days ) after the beginning of mechanical ventilation .
( 1 ) , scheppach et al . ( 2 ) , and benninger et al . ( 3 ) . in the first 1 - 3 months after the initial cholestasis
, the histological features of sc - cip are quite variable and can range from mild , nonspecific changes to findings consistent with chronic bile duct obstruction . within 4 - 12 months of the initial cholestasis
, a histological analysis shows uniformly progressive fibrosis of the ihd with bile duct proliferation , portal inflammatory infiltrates , periductal fibrosis , bridging fibrosis , and canalicular cholestasis .
the cross - sectional imaging findings for sc - cip in a retrospective literature review are multiple irregular strictures , dilatations , a beaded appearance , and wall thickening of ihd , which are mimicking primary sclerosing cholangitis ( psc ) ( 2 ) .
( 10 ) have reported that the earliest event in sc - cip may be extensive biliary cast formation with subsequent infections , and this is represented by intraductal filling defects in mrcp and erc .
several weeks after the initial cholestasis , multiple irregular strictures or dilatations with biliary cast formations can often be observed .
in addition , they reported that several months after the initial injury , advancing rarefaction of the small bile ducts and progressive sclerosis can often be observed . in our case ,
an increase in intraluminal attenuation in the diffusely thickened right main ihd was suspicious on the ct exam , and it was confirmed as biliary casts on erc .
however , biliary casts in the peripheral ihd or left main ihd were not detected in the contrast - enhanced ct exam .
irregular elongated filling defects on mrcp and erc , which are representative of biliary casts , were noted in both ihds and extended to the proximal cbd .
multiple irregular strictures , dilatations , and saccular ectasia were also seen in both ihds . however , there was no evidence of cbd stenosis or irregularities .
jaeger et al . ( 4 ) have reported that multifocal strictures and beading are only seen in the ihds without cbd involvement and that biliary casts formed in the ihds can extend to the cbd .
this finding in our study was consistent with the erc and mrcp findings of other sc - cip studies ( 2 , 4 , 6 , 9 ) .
we believe that the sc - cip imaging findings in the early stages are similar to those of typical sclerosing cholangitis , although biliary cast formation in the ihds is not a typical finding in primary or other forms of secondary sclerosing cholangitis . in the later stages of sc - cip ,
the cholangiography findings are similar to those of ischemic cholangitis and long - term psc , which consisted of the destruction of the biliary tree rather than the usual sclerosing cholangitis ( 7 , 8) .
radiologically , the differential diagnosis for biliary cast formation in sc - cip includes ischemic cholangiopathy , psc , and other forms of secondary sclerosing cholangitis .
ischemic cholangiopathy almost always occurs in transplanted livers as a consequence of complications and sometimes in other ischemic status , such as transarterial chemoembolization ( tace ) complications or hepatic artery injury .
however , it is still debatable whether sc - cip is an ischemic - like cholangiopathy .
biliary cast formation is extremely rare in primary or other forms of secondary sclerosing cholangitis .
in addition , most of the pathology in sc - cip involves the ihd and spares the cbd .
a clinical history that includes icu hospitalization will be helpful for suggesting sc - cip to a radiologist and for ruling out other causes of secondary sclerosing cholangitis .
with regard to the treatment of biliary casts in sc - cip , endoscopic removal of as many as possible is recommended , and udca can also be used ( 6 , 9 ) .
however , the progressive destruction of the biliary tree can not be prevented ; therefore , the only curative treatment option is liver transplantation .
( 1 ) have reported that in the first two years after discharge from the hospital , eight of the 26 ( 30% ) sc - cip cases underwent liver transplantation or were waiting for liver transplantation , due to severe progressive cholestasis .
( 4 ) have reported that 45 months after the initial injury , one of the 10 ( 10% ) sc - cip cases underwent liver transplantation , and eight patients appeared to have slowly progressive disease . a study has reported that sc - cip rapidly progresses to liver cirrhosis with a median survival of only 13 months if the patient does not undergo liver transplantation ( 7 ) . although establishing the prognosis of sc - cip is still ongoing , the progression of sc - cip is even more aggressive than that of other forms of secondary sclerosing cholangitis . in conclusion ,
however , a diagnosis of sc - cip should be considered in icu patients with biliary cast formation and sclerosing cholangitis of the ihd in their ct , mrcp and erc findings .
sclerosing cholangitis in critically ill patients ( sc - cip ) is a rare condition that is not familiar to many radiologists . 
 in addition , the associated imaging findings have not been described in the radiological literature . 
 we report a case of biliary cast formation with sc - cip and describe the radiological findings of ct , magnetic resonance cholangiopancreatography ( mrcp ) , and endoscopic retrograde cholangiography ( erc ) . 
 a diagnosis of sc - cip should be considered in intensive care unit ( icu ) patients with persistent cholestasis during or after a primary illness . 
 the typical ct , mrcp and erc findings include new biliary casts in the intrahepatic duct with multiple irregular strictures , dilatations , and relative sparing of the common bile duct .