Pyogenic Liver Abscess Following ERCP and Biliary Stenting: A Case Series of Two Patients and Clinical Implications

In the human body, the liver acts as a massive chemical processing plant, filtering blood and producing bile, a fluid that helps digest fats. This bile travels through a network of narrow tubes called ducts to reach the small intestine. Sometimes, stones form in these ducts, blocking the flow and causing pain, infection, or jaundice, a yellowing of the skin. To clear these blockages, doctors often use a procedure called endoscopic retrograde cholangiopancreatography, or ERCP. During this process, a flexible tube is guided down the throat and into the intestine to reach the bile ducts. Doctors can then use tiny tools to remove stones or place small plastic tubes, known as stents, to keep the ducts open. While this is a standard and life-saving treatment, it involves crossing a barrier between the sterile bile system and the bacteria-filled intestine, which carries a small risk of introducing infection into the liver.

Two researchers from a hospital in China recently shared the stories of two patients who developed a serious complication after undergoing this very procedure. In both cases, the patients had successfully undergone ERCP to treat blocked bile ducts caused by stones, but weeks later, they developed a pyogenic liver abscess. This is a pocket of pus that forms inside the liver when bacteria invade the tissue. The doctors described how these infections appeared, how they were identified using imaging scans, and how the patients were treated. Their report highlights that while this complication is rare, it is a real possibility that doctors must watch for, especially when patients have a history of biliary surgery or cysts in their liver.

The first patient was a forty-two-year-old woman who had been admitted for severe inflammation of the pancreas caused by gallstones. Her treatment involved a combination of surgeries, including the removal of her gallbladder, an operation to clear her bile duct, and an ERCP where a stent was placed to keep the duct open. She also had a small, fluid-filled sac, or cyst, in her liver that was drained during the operation. For several weeks, she seemed to be recovering well. However, after the stent was removed and the bile duct was swept clean with a balloon, she began to feel severe pain in the upper right side of her abdomen. She developed chills and a high fever that reached thirty-nine degrees Celsius. Blood tests showed her white blood cell count was high, and markers of inflammation were elevated. A CT scan, which uses X-rays to create detailed images of the inside of the body, revealed that the area in her liver where the cyst had been drained had turned into a large abscess. Doctors used ultrasound to guide a thin needle into the pocket of pus and drained it. The fluid they collected contained two types of bacteria commonly found in the gut: Escherichia coli and Klebsiella pneumoniae. After the drainage and a course of antibiotics, the abscess shrank significantly, and she was discharged from the hospital in good health.

The second patient was a sixty-two-year-old man who came in with gallstones that had moved into his common bile duct, causing a complete blockage and severe jaundice. He underwent an ERCP where doctors cut a small muscle at the entrance of the bile duct to allow for stone removal and placed a stent to keep the passage open. Six days after the procedure, he also developed intense pain, chills, and a fever of thirty-nine degrees Celsius. A CT scan showed a new, dark spot in the right side of his liver, measuring thirty-two millimeters by twenty-six millimeters, which was not present before the surgery. His blood tests were alarming; a protein called procalcitonin, which rises sharply during severe bacterial infections, was extremely high, and his kidneys were struggling to function. Like the first patient, he was diagnosed with a liver abscess caused by the same two types of bacteria. He underwent a similar procedure to drain the pus through his skin. Within two days of the drainage, his fever broke, and his blood markers began to return to normal. He was discharged a few days later and remained healthy at a follow-up visit a month later.

The authors of the report note that the development of such an abscess after ERCP likely happens because the procedure temporarily breaks down the natural barrier between the intestine and the bile ducts. This allows gut bacteria to travel backward into the liver. The presence of a stent can sometimes encourage bacteria to form a slimy coating, known as a biofilm, which protects them from the body's defenses. If the stent becomes blocked or if there are leftover stones, the bile can stagnate, creating a perfect environment for these bacteria to multiply and cause an infection. In the first case, the infection appeared exactly where a liver cyst had been drained, suggesting the bacteria may have settled in that specific space. In both cases, the bacteria found were typical of those that travel from the gut to the liver.

To catch these infections early, the doctors emphasize the importance of paying close attention to symptoms like fever, chills, and abdominal pain after the procedure. If a patient shows these signs, especially if they have elevated levels of inflammatory markers in their blood, a CT scan or ultrasound is necessary to look for an abscess. The report suggests that once an abscess is found, the most effective treatment is to drain the pus using a needle guided by imaging, combined with antibiotics that target the specific bacteria found. The study does not claim that ERCP is dangerous or that abscesses are common; rather, it serves as a reminder that even with successful procedures, the body can sometimes react in unexpected ways. By recognizing the signs early and treating the infection with drainage and medication, patients can recover fully, as both individuals in this series did. The key takeaway is that while the procedure is a vital tool for clearing blocked ducts, doctors must remain vigilant for this rare but serious complication, ensuring that any signs of infection are investigated immediately with modern imaging tools.