Current endoscopes are derived from a primitive system created in 1806-a tiny tube with a mirror and a wax candle. Although crude, this early instrument allowed the first view into a living body. The GI endoscopy procedure may be performed in either an outpatient or inpatient setting. Through the endoscope, a doctor can evaluate several problems, such as ulcers or muscle spasms. These concerns are not always seen on other imaging tests.

There are many types of weight-loss surgery, known collectively as bariatric surgery. Gastric bypass is one of the most common types of bariatric surgery in the United States. Many surgeons prefer gastric bypass surgery because it generally has fewer complications than do other weight-loss surgeries. Gastric bypass and other weight-loss surgeries make changes to your digestive system to help you lose weight by limiting how much you can eat or by reducing the absorption of nutrients, or both. Researchers also found that a bariatric surgical procedure reduces obesity and improves glucose tolerance in mice by increasing bile acids and altering gut microbes.

The exact cause of IBD is unknown, but IBD is the result of a defective immune system. IBD is diagnosed using a combination of endoscopy (for Crohn’s disease) or colonoscopy (for ulcerative colitis) and imaging studies, such as contrast radiography, magnetic resonance imaging (MRI), or computed tomography (CT). Several types of medications may be used to treat IBD: aminosalicylates, corticosteroids (such as prednisone), immunomodulators, and the newest class approved for IBD—the “biologics”. Several vaccinations for patients with IBD are recommended to prevent infections. Severe IBD may require surgery to remove damaged portions of the gastrointestinal tract.

Gastroesophageal reflux disease (GERD) is a common clinical problem, affecting millions of people worldwide. Patients are recognized by both classic and atypical symptoms. Acid suppressive therapy provides symptomatic relief and prevents complications in many individuals with GERD. Advances in diagnostic and therapeutic modalities have improved our ability to identify and manage disease complications. Here, we discuss the pathophysiology and effects of GERD, and provide information on the clinical approach to this common disorder. Some investigators prefer that inadequate response to twice-daily PPI treatment as refractory disease.

Colorectal cancer is the third leading cause of death from cancer in the United States. Scientists are trying to better understand which people are more likely to get certain types of cancer. Colorectal cancer is often a silent disease, developing with no symptoms at all. Studies show that some screening tests for colorectal cancer help find cancer at an early stage and may decrease the number of deaths from the disease.

GI disease may be limited to the GI tract (eg, reflux esophagitis, peptic ulcer, diverticular disease), be a manifestation of a systemic disorder (eg, inflammatory bowel disease), or present as a systemic disease resulting from a primary GI pathologic process. Chronically, GI disease can be complicated by malnutrition and deficiency states. In recent years, a number of mechanisms have been explored. These include disorders of the gut-brain axis, effects of diet, genetic factors, infections and disturbances in the intestinal microbiota, low-grade mucosal inflammation, immune activation, altered intestinal permeability, disordered bile salt metabolism or abnormalities in 5-hydroxytryptamine (5-HT) metabolism.

Viruses cause most cases of hepatitis. The type of hepatitis is named for the virus that causes it; for example, hepatitis A, hepatitis B or hepatitis C. Drug or alcohol use can also cause hepatitis. In other cases, your body mistakenly attacks healthy cells in the liver. During the past 60 years, NIAID-supported investigators have been involved in many important breakthroughs in hepatitis research, including the discovery of the hepatitis A and E viruses. Up to 70% of those chronically infected with hepatitis C develop chronic liver disease, and up to 20% develop cirrhosis.

A diverse spectrum of diseases affects the biliary system, often presenting with similar clinical signs and symptoms. These conditions include gallstones, acute calculus cholecystitis, acute acalculus cholecystitis, Mirizzi syndrome, chronic cholecystitis, cholangitis (recurrent pyogenic, primary sclerosing, primary biliary, autoimmune), biliary tract malignancies, biliary tract cysts, and others. Biliary disease is caused by abnormalities in bile composition, biliary anatomy, or function. The liver determines the chemical composition of bile, and this may be modified later by the gallbladder and the biliary epithelium. Cholesterol, ordinarily insoluble in water, comes into solution by forming vesicles with phospholipids (principally lecithin) or mixed micelles with bile salts and phospholipids.

Excessive alcohol consumption is a global healthcare problem. Chronic and excessive alcohol consumption produces a wide spectrum of hepatic lesions, the most characteristic of which are steatosis, hepatitis, and fibrosis/cirrhosis. Nonalcoholic fatty liver disease is also most common chronic liver disease because of the obesity epidemic affecting an estimated 80 to 100 million people. Obesity and metabolic syndrome (MS) are the most important risk factors identified in the development of NAFLD. The disease starts with fatty liver or hepatic steatosis and may progress to steatohepatitis with hepatic inflammation.

Alcohol and viral hepatitis B and C are common causes of cirrhosis, although there are many other causes. Diagnosis of cirrhosis can be suggested by history, physical examination and blood tests, and can be confirmed by liver biopsy. Treatment of cirrhosis is designed to prevent further damage to the liver, treat complications of cirrhosis, and preventing or detecting liver cancer early.  Transplantation of the liver is an important option for treating patients with advanced cirrhosis. The life expectancy for advanced cirrhosis is 6 months to 2 years depending on complications of cirrhosis, and if no donor is available for liver transplantation. The life expectancy is more that 12 years for a person with cirrhosis and no major complications.

Researchers have explored the hypothesis that antidepressants and psychological therapies can offer symptom relief for individuals with functional gastrointestinal GI disorders. Advanced endoscopic techniques should be considered for complex colorectal lesions without signs of deep submucosal invasion or advanced cancer. Several new devices that allow traction and countertraction, as well as electrosurgical knives with integrated water jets to lift and cut simultaneously, have recently been introduced and are under study. Based on the medical history, physical examination, doctors choose appropriate tests. Tests done on the digestive system include the following: Acid-related and reflux-related tests, CT and MRI, Endoscopy, Intubation of the digestive tract, Laparoscopy etc,.