Endoscopic Ultrasound (EUS)
What is an Endoscopic Ultrasound (EUS)?
Endoscopic Ultrasound (EUS) allows your doctor to examine the esopagheal and stomach linings as well as the walls of the upper gastrointestinal tract. EUS is also used to study organs near the gastrointestinal tract including the lungs, liver, gallbladder and pancreas. Your endoscopist will use a thin flexible tube called an endoscope that has a built-in miniature ultrasound probe. The endoscope is passed through your mouth to the area that needs to be examined. Your doctor will then use sound waves produced by the endoscopy to create visual images of the digestive tract.
What are the different EUS procedures?
- Upper EUS
This procedure allows your doctor to examine the upper gastrointestinal track, particularly the esophagus, the stomach and the duodendum (the beginning of the small intestines).
- Lower EUS
This procedure allows your doctor to examine the lower gastrointestinal track, including the colon and rectum. In this test, the endoscope is passed through the anus to the area that needs to be examined.
- EUS guided fine needle aspiration
This allows for your doctor to biopsy any lumps or lesions that have be detected on any prior imaging
- EUS guided fine needle injection
This procedure helps to alleviate pain caused by chronic pancreatitis or pancreatic cancer. Your doctor endoscopically injects either alcohol or phenol to the celiac nerve plexus to relieve pain and reduce the amount of pain relievers needed by the patient.
- EUS guided celiac plexus neurolysis
Patients with chronic pancreatitis or pancreatic cancer often times report pain that is difficult to control. The pain typically is triggered by the celiac plexus, a group of nerves that supply organs in the abdomen. Via EUS guidance, the pain is endoscopically treated by injecting either alcohol or phenol to the celiac nerve plexus. The goal of this procedure is to minimize the amount of pain a patient is experiencing and therefore minimize the use, and therefore side effects, of opiods. Pain minimization with celiac plexus neurolysis is expected for at least three months.
- EUS guided ablation of insulinomas
Insulinomas are insulin secreting tumors in the pancreas that cause patients to experience the symptoms of hypoglycemia. Treatment of insulinomas include medical management with dietary and medication intervention and surgery to resect the tumor. In cases whereby the tumor is small or the patient is not a surgical candidate, the insulinoma may be treated by EUS guided ablation which actually burns off the tumor.
- EUS pseudocyst drainage
This is a procedure in which sacs of fluid that gather both in and on the pancreas are removed. Most pseudocysts originate from leaks in the pancreas and do not require treatment but those that are large or enlarging may require drainage in order to prevent rupture or hemorrhage. Pseduocysts that complicate acute pancreatitis have a high probability to resolve without treatment and therefore should be monitored for 4-6 weeks before deciding on therapeutic management. Psuedocysts that complicate chronic pancreatitis are typically the result of outflow obstruction such as a stone, stricture or protein plug. These types of pseudocysts routinely require drainage.
When this happens, your doctor will insert one or more stents into the pseudocyst cavity for drainage into the stomach or duodenum. Patients who receive these stents are placed on antibiotics after placement. A CT scan is typically performed four weeks after cyst drainage to assess for resolution. The stent is typically removed, via endoscopy, 1-2 months after pseudocyst resolution.
- EUS guided fudicial placement
This procedure is used to track radiation therapy for cancer. Placement of gold fiducials is required for real-time tracking and delivery of a high-dose therapeutic beam of radiation to the tumor. The fudicial is used as a point of reference or a measure. To place the fudicial, an endoscope is used to localize the tumor, a 19-gauge fine needle is inserted in the target area which places the fiducials through the needle lumen. The position of the fiducials is verified by EUS and by fluoroscopy.
Reasons for a EUS
EUS is performed for both diagnostic and therapeutic treatment purposes. It can help your doctor figure out the cause of abdominal pain or abnormal weight loss. It also provides an opportunity for a close examination including a fine needle biopsy of any lumps or lesions found on prior imaging as well as a means to deliver different treatments to the esophageal and stomach lining.
For EUS of the upper GI tract, you should have nothing to eat or drink after midnight the night before the examination. It is important to discuss any medications you are taking with your doctor. Certain medication, such as anticoagulants, may need to be adjusted prior to the procedure.
During Your EUS
Prior to the procedure an anesthesiologist will give you sedation (Propofol) through an IV inserted in your arm. This medication will put you to sleep during the procedure. In some instances, your doctor and anesthesiologist may decide to use general anesthesia during the procedure. In all likelihood, you will most lie on your left side for the procedure.
During the EUS, the endoscope will be passed through your mouth into the area that needs to be visualized. Air is passed through the scope to assist with visualization of your organs. The endoscope does not interfere with your breathing. The EUS lasts one to two hours depending on the reason for the exam.
After Your EUS
You will be monitored in the recovery area until the effects of the sedatives wear off. You may experience some throat discomfort and thus it is recommended that you bring Cepacol lozenges to the appointment. You also may feel bloated due to the air passed through the scope during the procedure.
Unless instructed otherwise, you will be able to eat after your endoscopic procedure. You must have someone escort you home from the endoscopy suite
Typically, you will learn preliminary findings from your doctor prior to leaving the endoscopy suite. In cases where biopsies are taken, you are asked to call for results one to two weeks after your exam.
Although complications may occur, they are rare. Complications include:
- Bleeding at biopsy or treatment site (typically rare and controlled)
- Reaction to the sedatives
- Aspiration of food/fluid into the lungs (minimized if dietary restrictions adhered to prior to the procedure)
- Pancreatitis for those patients undergoing FNA or treatment of pancreas abnormalities
- Perforation or tear by endoscope (an extremely rare but serious complication)