ERCP and EUS Procedures: ERCP and EUS Procedures: EUS Tissue and Safe ERCP

0:00Welcome to Board Pearls. This is episode seven of seven of the ERCP and EUS Procedures chapter, in the Endoscopic Procedures module. This episode is endoscopic ultrasound, EUS, with a needle, and endoscopic retrograde cholangiopancreatography, ERCP, at its most careful. The first patient is a woman with a bulge in her stomach, and her case shows how the five EUS layers identify a subepithelial lesion, which lesions need tissue, which stains separate a gastrointestinal stromal tumor from a leiomyoma, and why biopsy needles have largely retired the cytopathologist in the room. A man with pancreatic cancer pain shows when the celiac plexus is destroyed and when it's only blocked. The second patient is a pregnant woman with cholangitis, and her case shows when ERCP can't wait in pregnancy and how radiation is kept minimal. A man with cirrhosis and a duct stone shows who bleeds after sphincterotomy and what's safer with coagulopathy. And the episode ends with how perforations are classified and why duodenoscopes spread resistant bacteria.

1:06Here's the first patient. A sixty-one-year-old woman had an esophagogastroduodenoscopy for reflux, which showed a smooth three-centimeter bulge in her gastric body covered by normal mucosa, with normal surface biopsies. It causes no bleeding or symptoms, and she's referred for EUS.

1:24A smooth bulge under normal mucosa is a subepithelial lesion, and EUS identifies it by the layer it comes from. EUS shows five layers of the gut wall: layer one, the superficial mucosa, which is hyperechoic; layer two, the deep mucosa, hypoechoic; layer three, the submucosa, hyperechoic; layer four, the muscularis propria, hypoechoic; and layer five, the serosa, hyperechoic. Hers is a homogeneous hypoechoic mass arising from layer four, the classic appearance of a gastrointestinal stromal tumor, GIST. Any lesion of two centimeters or more arising from the muscularis propria warrants tissue diagnosis by fine-needle biopsy and consideration of resection, because size in that layer correlates with malignant behavior, so her three-centimeter lesion is sampled.

2:19Her tissue has to separate two tumors that look the same on EUS. A leiomyoma also arises from layer four, is also hypoechoic, and resembles GIST, so immunohistochemistry on tissue distinguishes them: GIST is CD117, also called KIT, positive and DOG1 positive, while leiomyoma is desmin and smooth muscle actin positive and CD117 negative. Her core is CD117 and DOG1 positive, so she has a GIST, and she's referred for resection. GIST risk stratification by size and mitotic count, and surveillance of small gastric subepithelial lesions, are covered in chapter seven.

3:04Had her lesion sat in a different layer, the layer and its echo pattern would usually have narrowed the answer to one or two possibilities before any needle. A hyperechoic mass in layer three is a lipoma, typically incidental and benign. An anechoic layer three lesion with no internal echoes is a duplication cyst. A granular cell tumor is typically hypoechoic in layer three, a neuroendocrine tumor is hypoechoic in layer two or three, and a pancreatic rest is heterogeneous and often spans several layers.

3:35Her diagnosis needed tissue architecture, which is why a biopsy needle was used. Franseen-tip and fork-tip fine-needle biopsy needles give a higher diagnostic yield for solid pancreatic masses, lymphoma, GIST, and autoimmune pancreatitis, without rapid on-site evaluation by a cytopathologist, because they capture core tissue with its architecture preserved. Pancreatic adenocarcinoma can be diagnosed on cytology alone. But lymphoma needs architecture, such as a follicular pattern, and immunohistochemistry on intact tissue; GIST needs CD117 staining on tissue; and autoimmune pancreatitis needs storiform fibrosis, obliterative phlebitis, and more than ten immunoglobulin G4-positive plasma cells per high-power field. Rapid on-site evaluation was valuable with fine-needle aspiration, because immediate feedback confirmed adequate cellularity before the procedure ended, but modern biopsy needles produce diagnostic tissue regardless, so it's largely unnecessary and no longer mandatory in most settings. When the target is a pancreatic cyst instead, the fluid goes for carcinoembryonic antigen, glucose, amylase, cytology, and, when needed, KRAS, GNAS, and VHL testing.

4:55EUS can also treat pain, by reaching the nerves that carry it. A seventy-year-old man has unresectable adenocarcinoma of the pancreatic body with liver metastases and severe epigastric and back pain, and escalating opioids have left him constipated, sedated, and confused without controlling it. He's a candidate for EUS-guided celiac plexus neurolysis, which is performed for unresectable pancreatic cancer pain when opioids cause unacceptable side effects before they control the pain. Absolute alcohol, or alcohol mixed with bupivacaine, is injected into the celiac ganglia or plexus, which lies in front of and beside the celiac trunk. Alcohol denatures axonal proteins and disrupts the axons, interrupting visceral pain from the upper abdomen, while bupivacaine gives an earlier, shorter block. Central neurolysis bathes the whole plexus around the celiac trunk and aorta. Direct ganglion-targeted neurolysis injects smaller volumes into the visible ganglia and has shown better analgesia in some series, because it concentrates the agent where the ganglia are rather than dispersing it through surrounding fat.

6:00He's warned about the side effects before the procedure, because the common ones are expected. Serious adverse events are rare, about zero point two to zero point six percent, but transient minor ones are common. Diarrhea, in four to fifteen percent, is the most common: the plexus carries sympathetic outflow to the upper gut, and blocking it leaves parasympathetic activity unopposed, speeding transit and stimulating secretion, and it usually resolves within twenty-four to seventy-two hours. Orthostatic hypotension, from blunted sympathetic vascular tone, lasts hours to days. A transient pain flare in the first day is managed with a short increase in opioids. Retroperitoneal abscess and hematoma are rare. Paraplegia is rare but devastating: it follows inadvertent injection into a spinal radicular artery, because the artery of Adamkiewicz can arise near the level of the celiac trunk, and alcohol entering it infarcts the spinal cord. Careful technique with small volumes reduces that risk but can't eliminate it.

7:00Benign pain is handled differently, because the plexus regenerates. For chronic pancreatitis pain, a celiac plexus block with bupivacaine plus a corticosteroid, triamcinolone, is used instead of neurolysis. Destroying the plexus makes sense in cancer, where life expectancy is short and analgesia is the priority. In chronic benign pain, neurolysis gives inadequate long-term relief because the plexus regenerates, so a reversible steroid block that reduces inflammation and gives shorter-term relief is used without permanent destruction. That block helps about half of patients, for a limited time, as chapter twenty-six covers.

7:38ERCP is the procedure where care matters most in pregnancy, because it adds radiation to sedation. A twenty-eight-year-old woman, nineteen weeks pregnant, has fever, rigors, right upper quadrant pain, and jaundice, with a bilirubin of four point eight and a white count of seventeen thousand. Her ultrasound shows gallstones and a dilated duct, and a non-contrast magnetic resonance cholangiopancreatography, MRCP, shows a ten-millimeter stone in the distal duct.

8:08She has acute cholangitis from a duct stone in pregnancy, an indication that can't wait. ERCP in pregnancy is reserved for indications that can't be deferred until after delivery: biliary obstruction with cholangitis, severe gallstone pancreatitis with persistent obstruction, a duct stone with persistent obstruction or refractory symptoms, or a bile leak after cholecystectomy. Diagnostic ERCP is avoided entirely. Non-contrast MRCP is the imaging of choice for biliary anatomy, and radiation-free EUS is preferred when stone confirmation or tissue is needed without therapy. A woman at eight weeks with biliary colic, a normal bilirubin, and no cholangitis or persistent obstruction wouldn't meet that threshold, and the first trimester is when the fetus is most sensitive to radiation.

8:58Her fetus is protected by keeping radiation to a minimum. The American Society for Gastrointestinal Endoscopy and the Society of American Gastrointestinal and Endoscopic Surgeons recommend total fluoroscopy time under one minute when feasible; a lead apron over the abdomen and pelvis; pulsed fluoroscopy at the lowest acceptable rate, four to eight pulses per second; collimation to the smallest field; and no magnification unless it's needed. Last-image-hold and image-grab functions cut live fluoroscopy time. With these measures, the cumulative fetal dose is typically under one millisievert per ERCP, well below the fifty milligray threshold for measurable teratogenic risk. Where available, intraductal ultrasound can replace fluoroscopy to confirm the duct is clear. Wire-guided cannulation without contrast is sometimes feasible for straightforward stone removal from a known dilated duct, and wire-guided cannulation also lowers the risk of post-ERCP pancreatitis.

9:54Her sedation and position are adjusted as well. Propofol is preferred, midazolam is avoided, especially in the first trimester, and fentanyl is acceptable in moderate doses. The old Food and Drug Administration letter categories, B for propofol, D for midazolam, and C for fentanyl, were replaced in twenty fifteen by narrative risk summaries but persist as shorthand. Left lateral positioning prevents the uterus from compressing the aorta and vena cava. Fetal monitoring is appropriate after twenty-two to twenty-four weeks. When there's a choice, the second trimester is preferred, avoiding the first, when teratogenic risk is highest, and the third, when the risk of premature labor and the difficulty of positioning are greatest. She has ERCP under propofol, tilted to the left, with about forty seconds of pulsed fluoroscopy, a sphincterotomy, and stone removal.

10:45Sphincterotomy, which cleared her duct, carries its own bleeding risk, and the next patient shows who's most likely to bleed. A sixty-eight-year-old man with Child-Pugh B cirrhosis has a duct stone causing recurrent pain and jaundice, with an international normalized ratio, INR, of one point nine and platelets of fifty-eight thousand. Post-sphincterotomy bleeding occurs in one to two percent of cases overall and rises with anticoagulation. Its five classic risk factors are coagulopathy, anticoagulation within three days, cholangitis before the procedure, low endoscopist case volume, and bleeding during the procedure, and papillary stenosis after a failed precut adds risk. Each has a mechanism: coagulopathy and recent anticoagulation impair hemostasis at the cut, cholangitis makes the mucosa inflamed and friable, low volume brings less efficient technique and longer cautery, and bleeding during the procedure reveals a vascular anatomy that keeps bleeding.

11:44His coagulopathy changes the technique. In cirrhosis or coagulopathy, endoscopic papillary balloon dilation is often safer than a full sphincterotomy for duct stones, because it stretches the papillary opening and preserves the sphincter without leaving a cut surface to bleed. Large-balloon dilation after a limited sphincterotomy extends the same idea to large stones in selected patients. He has balloon dilation and stone extraction without bleeding, done by an experienced endoscopist, which also removes the low-volume risk factor.

12:18Perforation is rarer, and it's tied to the same cutting that opens the papilla. It occurs in less than one percent of ERCPs and is more common with precut or needle-knife sphincterotomy, because those cuts are made without the guidance of an established cannulated tract. The Stapfer classification describes it: type one is a free-wall duodenal perforation, type two periampullary, type three a ductal injury, and type four retroperitoneal air without a clinical correlate. Management depends on the size, location, and timing.

12:51Cholangitis after ERCP has a single cause, so it has a single prevention. It reflects incomplete drainage of an obstructed system, and it's prevented by ensuring complete biliary drainage at the first procedure rather than partial drainage with a stent alone. When complete drainage can't be assured, antibiotic prophylaxis is recommended.

13:11The duodenoscope itself can cause harm, and its design is the reason. Duodenoscope-transmitted infections, including outbreaks of carbapenem-resistant Enterobacteriaceae, particularly carbapenemase-producing Klebsiella pneumoniae, drove Food and Drug Administration action on reprocessing. The elevator at the scope's tip is a moving part with small crevices and channels where biofilm forms and survives high-level disinfection, passing from one patient to the next. The design that makes cannulation possible is the design that resists reliable cleaning. The mandated improvements are disposable elevator caps, disposable elevators, simplified designs that are easier to clean, fully disposable duodenoscopes, and enhanced reprocessing with documentation, with single-use components removing the reservoir for biofilm. Outside an outbreak, double high-level disinfection and ethylene oxide sterilization add no benefit under the twenty nineteen Food and Drug Administration transition recommendation and the twenty twenty-one multisociety guidance, because they reach the inside of a reusable elevator no better than standard disinfection while wearing the scope. Traceability, recording scope serial numbers, patient identifiers, reprocessing staff, and dates, lets any infection cluster be traced to specific pairings of scope and patient.

14:27Here are the traps the boards set in EUS. A subepithelial lesion is identified by its EUS layer. A layer four lesion of two centimeters or more needs tissue, and it isn't called a GIST without CD117 and DOG1. A hyperechoic layer three lipoma doesn't need a biopsy. Aspiration cytology isn't enough when lymphoma, GIST, or autoimmune pancreatitis needs architecture. Modern biopsy needles make rapid on-site evaluation largely unnecessary. Alcohol neurolysis isn't used for chronic pancreatitis pain. And before neurolysis, the patient is warned about diarrhea, orthostatic hypotension, a pain flare, and rare paraplegia.

15:14For ERCP, the traps are these. Diagnostic ERCP isn't done in pregnancy, when MRCP or EUS can answer the question. Fluoroscopy in pregnancy is kept under a minute, pulsed, collimated, and shielded, and MRCP is done without contrast. Cholangitis in pregnancy isn't left untreated because of the pregnancy. Midazolam is avoided in the first trimester, and a pregnant patient isn't laid flat. A coagulopathic patient with cirrhosis gets balloon dilation rather than a full sphincterotomy when it will do. Incomplete drainage needs antibiotics. And duodenoscope transmission is prevented by disposable elevator components and traceability, not by double disinfection or ethylene oxide.

15:57So, start to finish. Place a subepithelial lesion by its EUS layer: a hypoechoic layer four mass is a GIST or leiomyoma, sampled at two centimeters or more and stained for CD117 and DOG1, a hyperechoic layer three mass is a lipoma, and an anechoic layer three lesion is a duplication cyst. Use biopsy needles when architecture matters, which makes on-site cytology largely unnecessary. Offer alcohol neurolysis for opioid-refractory pancreatic cancer pain and a steroid block for chronic pancreatitis, warning about diarrhea, orthostatic hypotension, a pain flare, and rare paraplegia.

16:41Reserve ERCP in pregnancy for indications that can't wait, diagnose with non-contrast MRCP or EUS, and keep fluoroscopy under a minute, pulsed, collimated, and shielded, with left lateral tilt and propofol. Predict sphincterotomy bleeding from coagulopathy, recent anticoagulation, cholangitis, low volume, and bleeding during the procedure, and use balloon dilation in coagulopathic patients. Perforation occurs in less than one percent and is classified by Stapfer type, cholangitis is prevented with complete drainage or antibiotics, and duodenoscope transmission is prevented with disposable elevator components or single-use scopes plus traceability.

17:23That completes chapter twenty-nine. Chapter thirty is colonoscopy practice and quality.

17:30For the full chapter, the practice vignettes, and the topic-tagged question bank, head to board pearls dot com. You'll find the rest of the series on Apple Podcasts, Spotify, or wherever you listen to podcasts. That brings us to the end of episode seven of seven of chapter twenty-nine, and I'll see you in the next one.