In the passing decade, tremendous advances have been made in the field of endoscopy. Various diagnostic and therapeutic procedures can be performed without a scar on the skin. Endoscopy ultrasound is such a remarkable tool for changing the management of patients suffering from gastrointestinal disorders. As the name suggests, EUS is performing the ultrasound from within the GI tract. A miniature ultrasound probe is attached to the tip of the endoscope, helping in obtaining high-quality and informative pictures.
How the EUS is performed
After the fasting of at least 8 hours, Endoscopic ultrasonography is performed under sedation, making it a painless procedure. If tissue sampling is planned, blood thinners medications need to be stopped after discussion with the doctor. During EUS, structuring surrounding the esophagus, stomach, upper intestine, and lower part of the large intestine are studied. Tissue samples are also obtained if required, and now with the newer needles, even the biopsies can be done during the procedure. Patients suffering from the disorders of the gall bladder, bile duct, pancreas, and lymph node enlargement may benefit from the procedure.
Evaluation of the cause of Jaundice
Jaundice is a symptom that may be caused by swelling in the liver or obstruction to the flow of bile through the bile duct. Bile duct carries bile formed in the liver to the digestive tract. and is essential for the digestion of food, and excretion of cholesterol and bilirubin, the latter being a pigment formed during breakdown of hemoglobin. Obstruction to the flow of bile will lead to an increased level of bilirubin in the blood, which gives yellow discoloration to eyes and urine, a condition known as jaundice. Obstructed bile duct can also lead to pain in upper abdomen, and fever secondary to infection in the liver. Obstruction in the bile duct can be due to various causes such as stone, tumor, worms, compression of the bile duct by the enlarged glands. Patients coming with the history of fever, pain and jaundice are suspected to have obstruction in the bile duct, and ultrasound is often the first test in these patients. USG may show the presence of obstructed ducts but often fails to detect the cause. Endoscopic ultrasonography is extremely useful test to detect the cause of jaundice specially if the stones are the cause of obstruction of bile duct, many such stones migrating from the gall bladder. Once the stones are detected, removal can be done in the same setting, by another endoscopic procedure known as Endoscopic retrograde cholangiopancreatography or ERCP. Cancer of the bile duct, gall bladder and pancreas are the another common cause of bile duct obstruction leading to jaundice, and is more common in elderly. EUS can easily detect these tumors, and sampling can be done in the same setting without any risk of spread of the tumor.
Evaluation of Pancreatic pathologies
Pancreas is gland in the upper part of abdomen behind the stomach, main function being secretion of enzymes for digestion of food. Alcohol, smoking and gall bladder stones are the common risk factors for pancreatic pathologies such as acute pancreatitis, chronic pancreatitis and pancreatic cancer. Patients with acute pancreatitis can have severe pain in upper abdomen and vomiting. After treatment of the acute pancreatitis, further episodes should be prevented by treating the underlying cause. One of the common cause of acute pancreatitis is gall bladder stone, which may migrate in the bile duct and transiently block the pancreatic duct at ampulla, leading to acute pancreatitis. Stones causing acute pancreatitis may be very small, and may be missed by ultrasonography. EUS can essentially detect very small stones in the gall bladder, treating which will prevent further episodes of acute pancreatitis. Individuals consuming alcohol or having predisposing genetic factors, can suffer from the persistent pain in upper abdomen, which can be due to chronic pancreatitis, a condition which can lead to stone formation and dilatation of the duct pancreas. In the early stage, condition may be missed by the conventional techniques. EUS provides the highest level of information in this stage, and can change the management of the disease altogether. In patients with both acute and chronic pancreatitis, fluid may accumulate around the pancreas, forming a cyst known as pseudocyst. Best treatment of pseudocyst now a days, is drainage in the stomach and upper part of small intestine, under the EUS guidance. EUS guided drainage avoids the need of surgery and placement of external tubes. Patients with diabetes and history of smoking are at increased risk of cancer, the common symptoms are pain upper abdomen and jaundice. EUS can detect the smallest of cancer in the pancreas, define the extent and enable the tissue sampling without compromising the resectability. Cystic lesion in the pancreas are common and can be due to pancreatitis or may be due to tumor formation. EUS is best tool to define the nature of the lesion and is a useful guide for the further treatment.
Treatment of jaundice and vomiting in patients with pancreatic cancer
Patients with pancreatic lesion may suffer from vomiting and jaundice due to obstruction of stomach and bile duct respectively. In both the conditions, stent placement may be necessary depending upon the circumstances and tumor spread. EUS guided stenting is emerging as new technique for the treatment of jaundice and vomiting. Moreover once the conventional techniques fail, EUS is an useful rescue technique.
Evaluation of pain in the upper abdomen
Small stones in the gall bladder known as microliths and early chronic pancreatitis are common causes of upper abdomen pain, which are often missed by conventional techniques. EUS is the best performing test in such conditions enabling the early diagnosis and treatment.
Pain relief in patients with cancer
Many patients with cancer of upper digestive tract can have severe pain abdomen, which is not controllable by oral medications. EUS guided injection around the nerve fibers carrying the pain sensation is useful modality for the pain relief.
Control of bleed in patients with liver cirrhosis
Inpatients with cirrhosis of liver, veins of esophagus and stomach may dilate and are known as varices. Varices in the stomach require injection of special fluid known as glue. Placement of coils in the varix under the EUS guidance prior to glue injection makes the procedure very safe.
Evaluation of fever
Prolonged fever may be due to enlargement of the lymph nodes, which can be due to various diseases such as tuberculosis, sarcoidosis and tumor of lymph nodes such as lymphoma. Sampling of the nodes is necessary to define the cause and for further treatment. EUS is very safe in such conditions and enables the direct visualization and sampling the lymph nodes.
Purpose of innovation is to change the treatment of various diseases towards better and lesser invasive direction at a lesser criteria, EUS perfectly fits all these criteria.
