Duration of Antibiotic Therapy for Cholangitis

No randomized clinical trials have firmly established the duration of antibiotic therapy for the treatment of cholangitis. However, general guidelines are for antibiotic therapy to continue until biliary obstruction is completely relieved, biochemical liver function tests have improved or normalized, and the patient is afebrile for at least 48 hours. After successful biliary drainage by ERCP, a retrospective study comparing short-duration antibiotic therapy (3 days) with longer antibiotic coverage showed that 3 days of antibiotic therapy appears sufficient when adequate drainage has been achieved and fever is abating (van Lent et al, 2002).

Patients at risk for recurrent cholangitis, such as those with residual calculi or incompletely relieved obstruction from any cause, should remain on oral antibiotics until the biliary obstruction is completely relieved. Acceptable oral antibiotics for these types of patients include trimethoprim/sulfamethoxazole and levofloxacin or ciprofloxacin alone or in combination with metronidazole.

Transabdominal Ultrasound

TUS (see Chapter 13) is the least expensive and most universally available imaging modality to evaluate the biliary tree and gallbladder. As such, it is the preferred first diagnostic test when evaluating a patient with acute cholecystitis and/or cholangitis. US can reliably demonstrate intrahepatic and extrahepatic biliary dilation, but this can be absent in the case of an acute obstruction. In the presence of gallstones less than 10 mm in size and dilation of the CBD greater than 10 mm, CBD obstruction by gallstones is likely (Abboud et al, 1996). The sensitivity of US to detect CBD stones varies between 20% and 75%, with increased sensitivity in the case of multiple large stones within a dilatated CBD and less sensitivity in the case of stone impaction in the retropancreatic segment of the CBD.

Computed Tomography

Non–contrast-enhanced CT scan (see Chapter 16) overcomes the technical limitations of US, as it can detect impacted stones in the retropancreatic CBD segment; when performed with 2- to 3-mm slices, its sensitivity for detecting small stones is reported to range between 65% and 80% (Neitlich et al, 1997). However, because up to 25% of gallstones will have the same density as bile, the sensitivity of noncontrast CT does not exceed 80%.

In the case of cholangitis, intravenous (IV) contrast–enhanced CT scan can reveal inflammation and demonstrate thickness of the bile ducts. The arterial phase should reveal peripheral or periductal hypervascularization (Arai et al, 2003). Another important role for CT is to detect the complications of cholangitis, such as hepatic abscess (Fig. 43.2) and pylephlebitis (suppurative thrombosis of the portal vein). Finally, CT can reveal etiologies of biliary obstruction, other than a CBD stone, such as a tumoral mass; however, contrast material is associated with a risk of hypersensitivity or induced renal toxicity, particularly in underresuscitated patients or in the presence of hemodynamic instability.

FIGURE 43.2 Abdominal computed tomographic scan demonstrating a hepatic abscess involving the right hepatic lobe with surrounding inflammatory changes.

Magnetic Resonance Cholangiopancreatography

Magnetic resonance cholangiopancreatography (MRCP; see Chapter 17) provides imaging in a noninvasive manner that allows visualization by emphasizing the hyperintensity of stationary liquids, thus the use of this modality precludes the need for contrast injection to fully visualize the biliary system. Images obtained by MRCP are similar to those obtained by cholangiogram: stones appear as hypointense defects (lacking liquid) within the biliary system. However, MRCP cannot differentiate stones from air bubbles, sludge, or blood clots—all these lack liquid. A further limitation of MRCP is that it cannot detect stones less than 3 mm in size, nor can it detect impacted stones in the ampulla, which require evaluation of T1 images before and after gadolinium injection. The overall sensitivity of MRCP to detect CBD stones is 80% to 100%, and its specificity is excellent, varying between 90% and 100% (Hakansson et al, 2002; Kondo et al, 2001; Soto et al, 2000). It is important to recall that MRCP is purely a diagnostic modality, it is not therapeutic.

Endoscopic Ultrasound

Endoscopic ultrasound (EUS; see Chapter 14) is an invasive procedure that requires sedation or general anesthesia. Once it has been passed through the stomach and into the duodenum, the US probe is in close relationship to the CBD; by using a high US frequency (7.5 to 12 MHz), the resolution of EUS is exceptional (<1 mm), making it the gold standard in the detection of small gallstones or other obstructive etiologies. The major limitations of EUS are that it cannot be performed in patients with altered anatomy, such as those with a prior distal gastrectomy or gastric bypass, or in the presence of a significantly calcified pancreas or hilar biliary pathology.

Direct Cholangiography

Although historically considered the reference radiologic modality, direct cholangiography (see Chapter 18) for purely diagnostic purposes has been supplanted by less invasive cross-sectional imaging alternatives, which also provide additional anatomic detail related to adjacent organs to allow a more complete assessment. Retrograde or percutaneous cholangiography is largely limited to the first step of a therapeutic procedure (Gallix et al, 2006).

In addition to its inferior image quality, there are various complications associated with the use of direct cholangiography, including biliary infection, pancreatitis, and hemorrhage (Vidal et al, 2004).

Endoscopic Biliary Decompression (See Chapters 27 and 36)

ERCP and biliary decompression should be performed only after patients have been resuscitated and given systemic antibiotics, although an exception can be made for patients who do not respond to initial medical therapy or those who clinically deteriorate within 12 hours of beginning treatment. If the patient has mild to moderate cholangitis and is stable, an effort can be made to definitively clear the duct of calculi. However, if the patient is septic with hemodynamic instability, or if there is purulence within the duct, efforts to clear the duct completely should be deferred to another time, when the patient is more stable, and sepsis has resolved.

The procedure should be carried out in a monitored setting (endoscopy lab, intensive care unit, or operating theater) under either conscious sedation or general anesthesia. A side-viewing scope is used to visualize and cannulate the ampulla of Vater. Contrast is injected into the CBD under real-time fluoroscopy only in an amount that allows the level of the obstruction to be visualized, and a guidewire is passed across the obstruction. In acutely ill or septic patients, biliary decompression should be obtained with the least amount of manipulation and effort, and extended maneuvers to remove calculi or perform sphincterotomy should be avoided. A convenient method of decompression is with external nasobiliary drainage (ENBD), a drainage procedure done by placing a 5- to 7-Fr tube using a guidewire technique. ENBD has the advantage of being an effective drainage tool, without the need of a sphincterotomy, and it provides access for biliary cultures.

Another biliary drainage modality is internal drainage using a 7- to 10-Fr plastic stent in the bile duct, using a guidewire after selective cannulation of the bile duct. Two stent shapes are available: a straight type with flaps on both sides and a pigtail type to prevent dislocation. Advantages of this approach include minimal or absent discomfort and limited electrolyte or fluid shifts relative to transnasal biliary drainage. Disadvantages include the potential for stent clogging or loss of patency, risk of dislodgement, and the technical disadvantage for a sphincterotomy when a stent larger than 7 Fr is inserted.

In cases of difficult biliary cannulation, an endoscopic sphincterotomy (EST) may be performed. A common EST technique is to perform a high-frequency electric surgical incision of the duodenal papilla, using a sphincterotome selectively inserted into the bile duct. In contrast to EST for stone removal, when performed for drainage, only a limited incision is necessary. Bleeding, retroduodenal perforation, and pancreatitis are the most common complications after ERCP and sphincterotomy. Morbidity and mortality rates are much higher with sphincterotomy than with nasobiliary catheter drainage when patients are critically ill (Boender et al, 1995; Chawla et al, 1994; Leese et al, 1986). Complications commonly reported with EST are hemorrhage (2% to 3%) and pancreatitis (1.9% to 5.4%), and mortality rate is 0.4% to 1.3% (Cotton et al, 1991; Freeman et al, 1996).

Contraindications

Sphincterotomy is contraindicated in the presence of coagulopathy, systemic sepsis, and hemodynamic instability, with the exception of those patients who have clinically deteriorated after initial medical therapy.

As stated, emergent sphincterotomy to decompress the bile duct should be avoided in septic patients, and especially in elderly patients, because of potentially high mortality rates (18.8%). In the elderly, endoscopic drainage alone has been observed to result in lower morbidity (16.7%) and mortality (5.6%) rates than surgical (87.5% and 25.0%, respectively) or percutaneous drainage (36.4% and 9.1%, respectively) (Boender et al, 1995; Sugiyama & Atomi, 1997). It is important to emphasize that once control of sepsis has been achieved, sphincterotomy and more optimal biliary imaging can be obtained, thus defining the underlying obstruction and enabling definitive treatment for either a stone, tumor, or stricture (Lee et al, 2002).