Gastrointestinal Endoscopic Ultrasound Screening (EUS)

• Endoscopic ultrasound screening (EUS) combines endoscopy with ultrasound technology, enabling doctors to diagnose or evaluate abnormalities of the gastrointestinal tract accurately, especially when other diagnostic methods have been inconclusive.
• In addition to examining and assessing suspicious areas, EUS allows for the collection of tissue samples or small-scale interventions, such as administering targeted medication directly to organs. 
• Gastrointestinal EUS has only minimal side effects and high efficacy, alleviating patient concerns about undergoing procedures and facilitating a prompt return to normal life.

EUS is a minimally invasive procedure that combines endoscopy with ultrasound technology to diagnose gastrointestinal and intestinal disorders, as well as other conditions. The endoscope used is a small, flexible tube with a miniature ultrasound device at its tip, allowing for precision and flexibility during the procedure.

This specialized endoscope, known as an echoendoscope, can be inserted through the mouth or rectum and directed to specific locations as required by the doctor. This innovation significantly enhances the ability of doctors to detect abnormalities within the gastrointestinal tract and surrounding areas due to the greater clarity it provides.

• Additional diagnostic insights can be gained from the patient's symptoms, such as abdominal pain or abnormal weight loss, as EUS provides clearer visualization of the gastrointestinal tract.
• Abnormalities can be assessed, such as the growth of masses detected before endoscopy via other screening methods, including ultrasound scans and computed tomography (CT) scans. This enables doctors to obtain clearer images of those masses, leading to more detailed diagnoses and the accurate identification of their nature.
• If conclusions remain unclear after other methods, tissue sampling through EUS-guided fine needle aspiration can definitively diagnose conditions involving the pancreas, bile ducts, and gallbladder.
• It allows for the examination and diagnosis of masses located beneath the mucosal lining of the stomach, the upper small intestine, and the lower large intestine.
• It provides valuable information to doctors regarding the extent of gastrointestinal cancers and helps identify whether the cancer has spread to nearby lymph nodes or vital nearby organs, such as blood vessels. Some patients may undergo tissue sampling using EUS to facilitate further examination and determine appropriate treatment strategies thereafter.

EUS aids in diagnosing the characteristics of lesions beneath the mucosal lining of the upper gastrointestinal tract (esophagus, stomach, and upper small intestine), the walls of the lower large intestine and rectum, as well as nearby organs comprising the pancreas, liver, and gallbladder. The use of EUS facilitates the detection of additional abnormalities beyond examinations conducted with computed tomography (CT) scans or magnetic resonance imaging (MRI) when there are indications present, such as:

• A need for a biopsy of a tumor tissue or drainage of cyst fluid within the pancreas.
• A need for a biopsy of lesions located beneath the mucosal lining of the stomach, upper small intestine, lower large intestine, and rectum.
• A need for further diagnosis of chronic pancreatitis.
• A need to access cancerous areas in the pancreas, stomach, large intestine, or rectum to confirm the nature and severity of the cancer, or to determine if the cancer has spread to nearby lymph nodes or blood vessels.
• A need to examine polyps in the gallbladder.
• A need for the delivery of targeted medication to the pancreas to alleviate pain in chronic pancreatitis cases.

The appropriate guidance from the doctor regarding EUS will depend on whether they intend to examine the upper gastrointestinal (GI) tract or the lower GI tract. Basic advice for individuals preparing for the procedure is as follows:

• Patients must fast from food and water and ensure the readiness of the colon to ensure clear visibility and unobstructed access for the endoscope.
• It is crucial that individuals undergoing the examination inform the doctor of any allergies, whether related to food or medication, or whether they are currently taking any medications, as the doctor may need to administer medication prior to EUS.
• After the procedure, patients should prioritize having someone to care for them, as they may experience drowsiness or confusion due to the pre-procedure medication.

For upper gastrointestinal (GI) examinations, the doctor will administer a throat spray to numb the area before the procedure. Patients will be positioned on their left side and receive sedation medication intravenously for relaxation. The doctor will then insert the endoscope through the mouth, into the esophagus, stomach, and upper small intestine. Generally, this procedure takes approximately 30-60 minutes to complete while the patient is asleep.

For lower gastrointestinal examinations, patients will receive sedation medication and be positioned on their left side with their back facing the doctor. This examination typically takes about 30-60 minutes to complete.

• Dry throat or cracked lips may occur from an upper gastrointestinal endoscopy.
• Nausea and vomiting.
• Abdominal bloating and gas.
• Some patients may experience abdominal pain or cramping.

Severe side effects are rare, but if a patient experiences serious symptoms beyond those mentioned earlier, such as high fever, chest pain, severe dizziness, or bleeding from the biopsy site, they should contact the doctor who performed the procedure or go to the hospital where the endoscopy was performed immediately.

Performing EUS requires a specialized doctor to ensure effectiveness and precision. This enables clear identification of the disease and prompt treatment. At Samitivej Hospital, Bangkok, Thailand our experts in endoscopic screening will put your mind at rest and leave you feeling confident about making a full recovery and returning to your desired lifestyle quickly and safely.

Reference: 

• https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/endoscopic-ultrasound
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4952290/