What is Endoscopic Ultrasound (EUS)?
An EUS is a type of endoscopic examination which uses a hybrid endoscope (camera) - it has a lens allowing limited visualization of the inner lining of the gastrointestinal tract as well as an ultrasound probe. Using the internal viewing lens, the scope is inserted into the mouth and down into the stomach and the first part of the small intestine. Once the required position is achieved, the small ultrasound probe emits sound waves which bounces off the surrounding structures, such as the stomach, small intestine, pancreas, bile ducts, and liver. These sound waves are then recaptured by the probe and converted into black and white images that are then interpreted by your doctor. This procedure is typically performed in an outpatient setting, and usually takes between 20 and 45 minutes.
Why do I need an EUS?
An EUS allows the gastroenterologist to be upfront and personal with the pancreas!
Jokes apart, As the pancreas is located right next to the stomach and small intestine, EUS allows the physician to get excellent images of the pancreas and the terminal part of the bile duct. EUS usually complements other modalities of imaging such as CT scan or MRI scans. EUS is an excellent test for evaluating many different kinds of diseases that can occur in the pancreas including evaluation of pancreatic masses or cysts, chronic pancreatitis, mass lesions in the stomach as well as lymph nodes. EUS can also be used to obtained tissue from multiple organs or lesions.
Common reasons that patients are referred for an EUS of the pancreas include evaluation of abnormal findings on a CT (CAT scan), MRI, or ultrasound of the abdomen, for investigation of abnormal blood tests such as elevated liver function tests (AST, ALT, bilirubin) or elevated pancreatic enzymes (amylase, lipase) and for certain types of abdominal pain.
Can biopsies be taken at the time of my EUS?
Usually yes! It depends on the location of the lesion/area of interest. Pancreatic biopsies are the most common biopsies done.
The type of biopsies done during EUS is called as fine needle aspiration (FNA) or fine needle biopsy (FNB) and are done using special purpose-built tiny needles and very small amounts of tissue or cells are obtained. Using visualization from the EUS probe, the physician is able to direct the needle to the exact location of interest.
I already had a CT scan or MRI. How is the EUS going to add anything more?
A CT scan or MRI scan can pick up lesions in the pancreas 70 – 82% of the time based on studies. EUS can often visualize details of the pancreas that may not be seen with either CT or MRCP.
Some patients are claustrophobic and may choose to undergo EUS to evaluate abnormal findings found on other modalities. There is no exposure to radiation, no need for contrast to be given and biopsies of the pancreas or lesions adjacent to the esophgus, stomach or duodenum was easily be viewed and if indicated, biopsies obtained with minimal pain to no pain.
Are there any risks of having an EUS?
EUS is a safe procedure but as with any endoscopic procedure, there is a small risk of causing bleeding, infections or a tear of the GI tract (called a perforation) and this may rarely warrant surgery for correction. The risk of severe complications from EUS is very low, less than 1% of the time in most cases.
Biopsies/FNA of the pancreas can also result in bleeding, infection, or acute inflammation of the pancreas (called acute pancreatitis). FNA of pancreatic cysts can result in infection of the cyst. This has been reported to occur in 1-2% of cases. Your physician may give you an antibiotic during the procedure to prevent infection and may prescribe a short course of oral antibiotics after the procedure.
What do I have to do to prepare for the EUS procedure?
Your stomach should be empty to allow an effective and safe examination.
You should not eat or drink anything, including water, for about 8 hours prior to your endoscopy (we will usually ask that you fast from midnight onwards on the day of your procedure).
Most medications can be continued prior to the exam but some medications such as aspirin or blood thinners may need to be stopped and we will give you instructions based on your individual circumstance. We encourage you to ask the physician specifically about these medications.
If you are diabetic, you will need to monitor your blood glucose carefully on the day prior to your procedure. We will give you specific instructions, if you are on insulin or take oral hypoglycemic agents like Glyburide or any of the newer drugs. We will try and schedule your procedure(s) early in the morning on the planned date.
Occasionally, we may ask you to get clearance from your cardiologist or another specialist for the procedure, usually from an anesthesia perspective.
What happens on the day of my procedure?
We will ask you to come an hour prior to your scheduled time to register and be admitted to our endoscopy unit (we do procedures at the hospital or at the ambulatory surgical center). The nursing staff will help you change into a comfortable gown and place you on a stretcher. An IV line will be placed to help us give you fluids and medications for the procedure. You will be asked to complete a health questionnaire, confirm your consent for the procedure and may meet a member of the anesthesia staff. Once the documentation and safety checks have been completed, you will be taken to the procedure room and asked to lie on your left side. You will then be given anesthesia or moderate sedation and go off to sleep. Once the procedure is completed, you will wake up and usually experience no pain or discomfort. Occasionally, people may complain of a sensation of bloating.
You will be taken to the recovery area and be monitored for about 30 mins prior to being discharged home.
You will need to have a driver pick you up from the unit and drive you home. Ideally, there should be someone with you at home to supervise your recovery as you may experience some drowsiness or groggy feeling as the sedative/anesthetic agent works its way out of your body.
1. We strongly urge you to not drive on the day of your procedure as your reflexes may be slower that you anticipate.
2. For safety reasons, you cannot use a taxi or public transportation to go home.
3. We strongly urge you to defer planning or making any legal decisions for up to 24 hours after the procedure, to ensure that your mind is clear and unaffected from the residual effects of anesthesia or moderate sedation.
4. We recommend not making any travel plans for up to a week after your procedure. This varies greatly – please discuss any planned or upcoming travel with Dr. Siddique at the time of scheduling.
What other procedures can be done utilizing EUS?
Due to the hybrid scope, views of the lumen of the bowel as well as views through the walls into the adjacent organs can be obtained. This permits injection or introduction of various small caliber tools in the least invasive manner. In patients with chronic pain from either pancreatitis or pancreatic cancers, pain relief can be offered using either Celiac plexus blocks (numbing the nerve center that is responsible for producing pain) or celiac plexus neurolysis (destroying the nerve center that is responsible for producing pain). In patients with acute pancreatitis with pancreatic fluid collections that are symptomatic, EUS guided drainage can be offered. There are a variety of other procedures that can be offered with EUS.