Ascending cholangitis

Ascending cholangitis, also known as acute cholangitis or simply cholangitis, is inflammation of the bile duct, usually caused by bacteria ascending from its junction with the duodenum (first part of the small intestine). It tends to occur if the bile duct is already partially obstructed by gallstones. Physical examination findings typically include jaundice and right upper quadrant tenderness. This was assumed in the past to be present in 50–70% of cases, although more recently the frequency has been reported as 15–20%. This combination of symptoms indicates worsening of the condition and the development of sepsis, and is seen less commonly still. In the elderly, the presentation may be atypical; they may directly collapse due to sepsis without first showing typical features. In people with AIDS, a large number of opportunistic organisms has been known to cause AIDS cholangiopathy, but the risk has rapidly diminished since the introduction of effective AIDS treatment. Cholangitis may also complicate medical procedures involving the bile duct, especially ERCP. To prevent this, it is recommended that those undergoing ERCP for any indication receive prophylactic (preventative) antibiotics. The presence of a permanent biliary stent (e. g. in pancreatic cancer) slightly increases the risk of cholangitis, but stents of this type are often needed to keep the bile duct patent under outside pressure. and allows bile to flow freely through. The continuous forward flow of the bile in the duct flushes bacteria, if present, into the duodenum, and does not allow the establishment of an infection. The constitution of bile—bile salts resulting from obstruction in the bile duct widens spaces between the cells lining the duct, bringing bacterially contaminated bile in contact with the blood stream. It also adversely affects the function of Kupffer cells, which are specialized macrophage cells that assist in preventing bacteria from entering the biliary system. Finally, increased biliary pressure decreases production of IgA immunoglobulins in the bile. This results in bacteremia (bacteria in the blood stream) and gives rise to the systemic inflammatory response syndrome (SIRS) comprising fever (often with rigors), tachycardia, increased respiratory rate and increased white blood cell count; SIRS in the presence of suspected or confirmed infection is called sepsis. usually after 24–48 hours of incubation. Bile, too, may be sent for culture during ERCP (see below). The most common bacteria linked to ascending cholangitis are gram negative bacilli: Escherichia coli (25–50%), Klebsiella (15–20%) and Enterobacter (5–10%). Of the gram positive cocci, Enterococcus causes 10–20%.

Given that ascending cholangitis usually occurs in the setting of bile duct obstruction, various forms of medical imaging may be employed to identify the site and nature of this obstruction. The first investigation is usually ultrasound, as this is the most easily available. A better test is magnetic resonance cholangiopancreatography (MRCP), which uses magnetic resonance imaging (MRI); this has a comparable sensitivity to ERCP.

Cholangitis requires admission to hospital. Intravenous fluids are administered, especially if the blood pressure is low, and antibiotics are commenced. Empirical treatment with broad spectrum antibiotics is usually necessary until it is known for certain which pathogen is causing the infection, and to which antibiotics it is sensitive. Combinations of penicillins and aminoglycosides are widely used, although ciprofloxacin has been shown to be effective in most cases, and may be preferred to aminoglycosides because of fewer side effects. Metronidazole is often added to specifically treat the anaerobic pathogens, especially in those who are very ill or at risk of anaerobic infections. Antibiotics are continued for 7–10 days. Stones may be removed either by direct suction or by using various instruments, including balloons and baskets to trawl the bile duct in order to pull stones into the duodenum. Obstructions that are caused by larger stones may require the use of an instrument known as a mechanical lithotriptor in order to crush the stone prior to removal. Obstructing stones that are too large to be removed or broken mechanically by ERCP may be managed by extracorporeal shock wave lithotripsy. This technique uses acoustic shock waves administered outside the body to break down the stones. An alternative technique to remove very large obstructing stones is electrohydraulic lithotripsy, where a small endoscope known as a cholangioscope is inserted by ERCP to directly visualize the stone. A probe uses electricity to generate shock waves that break down the obstructing stone. Rarely, surgical exploration of the common bile duct (termed choledochotomy), which can be performed with laparoscopy, is required to remove the stone. Narrowed areas may be bridged by a stent, a hollow tube that keeps the duct open. Removable plastic stents are used in uncomplicated gallstone disease, while permanent self expanding metal stents with a longer lifespan are used if the obstruction is due to pressure from a tumor such as pancreatic cancer. A nasobiliary drain may be left behind; this is a plastic tube that passes from the bile duct through the stomach and the nose and allows continuous drainage of bile into a receptible. It is similar to a nasogastric tube, but passes into the common bile duct directly, and allows for serial x ray cholangiograms to be done to identify the improvement of the obstruction. The decision on which of the aforementioned treatments to apply is generally based on the severity of the obstruction, findings on other imaging studies, and whether the patient has improved with antibiotic treatment.

Acute cholangitis carries a significant risk of death, the leading cause being irreversible shock with multiple organ failure (a possible complication of severe infections). Risk factors indicating an increased risk of death include older age, female gender, a history of liver cirrhosis, biliary narrowing due to cancer, acute kidney injury and the presence of liver abscesses. Complications following severe cholangitis include kidney failure, respiratory failure (inability of the respiratory system to oxygenate blood and/or eliminate carbon dioxide), abnormal heart rhythms, wound infection, pneumonia, gastrointestinal bleeding and myocardial ischemia (lack of blood flow to the heart, leading to heart attacks).

Dr Jean Martin Charcot, working at the Salpêtrière Hospital in Paris, France, is credited with early reports of cholangitis, as well as his eponymous triad, in 1877. ERCP is generally performed by internal medicine or gastroenterology specialists. In 1992 it was shown that ERCP was generally safer than surgical intervention in ascending cholangitis.