EUS of bile-duct hydatid membrane.

A 28-year-old man was referred because he had experienced high-grade fever, right upper-quadrant pain, and jaundice for the previous 5 days. A physical examination revealed fever and icterus. The results of laboratory tests were suggestive of sepsis with obstructive jaundice. A clinical diagnosis of acute cholangitis was established.

Transabdominal US showed a 3.2 × 3.4-cm cyst in the right lobe of the liver, dilatation of the biliary system up to the lower end of the common bile duct (CBD), and biliary sludge in the gallbladder. EUS was performed with a linear echoendoscope (Pentax EG-3830UT; Pentax, Tokyo, Japan) and the use of a Hitachi Avius processor (Hitachi, Tokyo, Japan) before ERCP to discover the cause of the cholangitis.

Linear EUS from the stomach revealed multiple curvilinear, leaflet-shaped, rounded, irregular structures within the dilated CBD and the common hepatic duct (Figs. 1 and 2). These structures were hyperechoic and multilayered, with intervening anechoic areas without acoustic shadowing, indicating membranous structures folded many times (Figure 3, Figure 4, and 5; Video 1, available online at www.VideoGIE.org).

Figure 1

Linear EUS view from stomach showing curvilinear, leaflet-shaped echogenic structures within dilated common bile duct suggestive of hydatid membranes. IVC, inferior vena cava.

Figure 2

Another linear EUS view from stomach showing curvilinear, leaflet-shaped echogenic structures within dilated common bile duct suggestive of hydatid membranes.

Figure 3

EUS view showing multiple, rounded, hyperechoic, irregular hydatid membranes visualized within common bile duct.

Figure 4

Another EUS view showing multiple, rounded, hyperechoic, irregular hydatid membranes visualized within common bile duct.

Figure 5

EUS view showing hydatid membranes to be hyperechoic and multilayered, with intervening anechoic areas without acoustic shadowing. CBD, common bile duct.

The structures were floating inside the CBD, suggestive of hydatid membranes (Figure 1, Figure 2, and 6). A cholangiogram revealed a dilatated CBD with multiple irregular filling defects formed by the hydatid membranes (Fig. 7). ERCP with biliary sphincterotomy and balloon sweeping resulted in clearance of the CBD with expulsion of multiple bile-stained and whitish hydatid membranes (Fig. 8, Video 1). There was significant improvement in the patient’s clinical condition after ERCP. Follow-up US after 2 weeks revealed a normal CBD and a decrease in the size of the liver cyst.

Figure 6

Floating hydatid membrane seen within common bile duct.

Figure 7

Cholangiographic view revealing a dilated common bile duct with multiple irregular filling defects formed by the hydatid membranes.

Figure 8

Endoscopic image showing bile-stained hydatid membranes being ballooned out.

Hepatic hydatid cyst rupture into the bile ducts (intrabiliary rupture [IBR]) is the most common and serious adverse event of hepatic cystic echinococcosis, occurring in 2% to 42% of cases. The clinical presentations of rupture include fever, right upper abdominal pain, acute cholangitis, acute pancreatitis (rare), liver abscess, and septicemia. Early diagnosis and treatment of IBR is crucial because mortality is high when obstruction of the biliary ducts occurs, leading to cholangitis and septicemia.

The mechanism of IBR is proposed to be based on 3 factors: the presence of small bile duct radicles in the pericyst, the condition of the echinococcal cyst wall, and the pressure level of the echinococcal cyst contents. Enlargement of the cyst stretches and compresses the bile duct, and intracystic pressure also increases with higher cyst diameter. In patients with larger cyst diameters, thinning of the walls of nearby biliary ducts will occur, and the risk of IBR will increase.

IBR can be diagnosed by US, CT, or magnetic resonance imaging in the presence of clinical features of obstructive jaundice or cholangitis. US and CT can demonstrate the place of rupture in 25% to 77% of cases. EUS, by demonstrating the presence of mobile hydatid membranes or cystlike material, may be useful when other imaging modalities are inconclusive or unavailable.

The treatment of choice of IBR is surgery, although some cases can be managed by ERCP. ERCP is both diagnostic and therapeutic in IBR; removal of the hydatid membranes relieves the jaundice and cholangitis.

Disclosure

All authors disclosed no financial relationships relevant to this publication.