Gastroenterologist

Esophageal dilation.

Year 1998
Nostrant TT. Nandi PS.
Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109, USA.
Esophageal dilation, a technique developed four centuries ago, continues to be an important method of treating the symptom of dysphagia in patients with luminal narrowing of the esophagus. Dilation is safe, with < 0.5% chance of perforation and bleeding and a 0.01% risk of death. Mercury bougienage (Maloney dilators), hollow polyvinyl dilators (Savary-Guillard), and balloon dilators (Through the Scope) are the principal types of dilators in use today. Few trials have compared the differing dilating methods. The results of these trials are mixed, and further randomized trials are necessary to determine if any technique has advantages in efficacy and cost. Although most patients successfully treated with dilation suffer with peptic strictures, those with nonpeptic strictures due to lower esophageal mucosal rings, corrosive injury, and radiation injury can also be treated effectively with dilation. By reviewing the current literature, effective treatment algorithms can be used with patients suffering from dysphagia due to various types of strictures.

Helicobacter pylori and gastric cancer: what is the real risk?

Year 1998
Crespi M. Citarda F.
Service of Environmental Carcinogenesis, Epidemiology and Cancer Prevention, and the Gastroenterology Unit, Regina Elena Cancer Institute, Rome, Italy.
Some epidemiological data point to an association between infection from Helicobacter pylori (Hp) and gastric cancer, although several unresolved issues still cast doubts on the real weight of this association. These issues are as follows: the male-to-female ratio of gastric cancer ranges from 4:1 to 1.5:1 in all studies, whereas the prevalence of Hp infection is the same in both sexes; the prevalence of Hp infection is as high as 90% in several developing countries where the frequency of gastric cancer is very low; the acquisition of the infection at a young age, considered very important with regard to the risk for cancer, varies from 4.2% to 83% in several countries in which the mortality for stomach cancer is approximately 10 in 100,000; and the incidence of cancer in patients with a duodenal ulcer is half that of the general population, but Hp infects up to 100% of these patients. In the sequence of events that leads to gastric cancer, Hp appears to play a role only in the very initial steps, as a causative agent of chronic inflammation. The further events that cause gastric atrophy, intestinal metaplasia, dysplasia, and cancer are multifactorial, involving environmental agents and the host response. It is therefore inappropriate to consider Hp a direct carcinogen for humans. This also applies to specific strains of the bacterium such as the cagA gene. In fact, Hp infection is widespread in humans, and only a small minority will ever be affected by peptic ulcer and cancer.

Radiologic management of hepatolithiasis.

Year 1998
Wittich GR. vanSonnenberg E. Goodacre BW.
Department of Radiology, University of Texas Medical Branch, Galveston 77555-0709, USA.
We describe the diagnostic workup and therapeutic management of patients with hepatolithiasis from the viewpoint of the interventional radiologist. The diagnosis is best established by direct cholangiography such as percutaneous transhepatic cholangiography or endoscopic retrograde cholangiography. We consider percutaneous transhepatic stone removal a highly successful, minimally invasive, and safe procedure. Access can be gained to the biliary system in almost 100% of patients and complete stone clearance through percutaneous techniques, including stone fragmentation, removal of stones and fragments by baskets, and dilatation of underlying strictures in more than 90%. The role of these radiologic techniques is discussed vis-a-vis endoscopic and surgical alternatives.

Chronic pancreatitis: a historical and clinical sketch of the pancreas and pancreatitis.

Year 1998
Pitchumoni CS.
New York Medical College and Our Lady of Mercy Medical Center, Bronx 10466, USA.
Chronic pancreatitis (CP), a disease described only in 1946 by Comfort and colleagues is currently a global disease. Chronic alcoholism, albeit is the most frequent etiologic factor for the disease in most of the affluent nations, a form of CP of undetermined etiology, tropical calculous pancreatitis (nutritional pancreatitis, Afro-Asian pancreatitis, or tropical calculous pancreatopathy) has been recognized to be prevalent in many developing nations. Hereditary pancreatitis inherited as an autosomal dominant disease is reported from all parts of the world. A landmark is the recent discovery of a gene that transmits the disease. Nearly 10% of cases of CP are truly "idiopathic" with no identifiable cause. Recent studies indicate that the idiopathic variety of CP has two subsets--a juvenile form and a senile or late onset form, with distinct clinical features. It is extremely rare to see CP secondary to hyperlipidemia or hypercalcemia. These etiologic associations appear to be overemphasized. Epidemiological studies indicate that alcoholism is growing in incidence all over the world along with an increase in all alcohol-associated disorders such as cirrhosis of the liver or pancreatitis. A genetic predisposition to alcoholic pancreatitis is suspected based on population studies, but not proven. The influence of cigarette smoking in enhancing alcohol-induced injury to the pancreas underscores the health hazard associated with alcoholism and cigarette smoking--two habits that often coexist in many individuals. The recent finding that all forms of CP are premalignant further emphasizes the need to enforce preventive measures. The hope is that CP is a preventable disease. The despair is that alcoholism is increasing and spreads across geographic and religious boundaries.

Tests of the liver: use and misuse.

Year 1998
Aranda-Michel J. Sherman KE.
University of Cincinnati Medical Center, Division of Digestive Diseases, OH 45267, USA.
Physicians frequently order batteries of tests that are used to assess liver injury or function. These tests are frequently ordered to screen for disease. However, a lack of understanding of the nature of the assays and the laboratory assignment of normal versus abnormal often leads to unnecessary workup or missed disease. We attempt to describe the nature of the most commonly used laboratory tests for liver disease, including alanine and aspartate aminotransferases, alkaline phosphatase, bilirubin, and gamma glutamyl transpeptidase. In addition, the role of functional tests of the liver, including prothrombin time, and metabolite clearance tests, such as aminopyrine and monoethylglycinexylidine, are examined.

Role of motility measurements in managing upper gastrointestinal dysfunction.

Year 1998
Snape WJ Jr.
University of California, Irvine, USA.
Nausea, vomiting, and abdominal pain are common symptoms that suggest many diagnoses. The patient's symptoms may be related to an anatomical defect such as a peptic ulcer or a mechanical small bowel obstruction. However, no anatomical abnormality may be identified despite radiological, endoscopic, or laboratory studies. The cause of the patient's symptoms may have significant impact on the patient's quality of life (nonulcer dyspepsia) and life span (intestinal pseudo-obstruction). Abnormal antroduodenal motility may be the underlying cause of the patient's symptoms. Normally, coordinated phasic contractions in the stomach and small intestine maintain digestion and absorption of food. A prolonged set of phasic contractions (phase 3 of the migrating complex) begins in the stomach and propagates down the small intestine to excrete nondigestible foods, bacteria, and dead cells. Any disturbance in the normal motility pattern can lead to maldigestion and symptoms of upper intestinal dysfunction. Objective tests of motility disturbances in the stomach and small intestine include measurement of gastric emptying, intestinal transit, contractions of the stomach and duodenum, and electrogastrography. Abnormal antroduodenal motility may be secondary to an abnormality in the smooth muscle (myopathy) or the nerves in controlling smooth muscle contractions (neuropathy). Antroduodenal motility measurements may help identify a partial small bowel obstruction, the cause of small intestinal overgrowth, and the cause of chronic abdominal visceral pain. Motility studies may suggest useful drugs for correcting the underlying pathophysiology and relieving symptoms.

Fecal occult blood testing: clinical value and limitations.

Year 1998
Simon JB.
Division of Gastroenterology, Queen's University, Kingston, Ontario, Canada.
Occult blood in the stool can be detected by chemical (guaiac), heme-porphyrin, or immunological methods. Each has advantages and disadvantages, with the guaiac slide test Hemoccult II (SmithKline Diagnostics) remaining the most widely used. Various technical factors affect its clinical performance, most notably whether the slides are rehydrated before processing; hydration increases test sensitivity for colorectal cancer but markedly decreases specificity, resulting in a large number of false-positive reactions that require invasive and expensive colonic workup. Newer immunological tests generally have high sensitivity, but poor specificity remains an important problem. In clinical screening situations, unhydrated Hemoccult has about 50% sensitivity for colorectal cancers and about 98% specificity. Only 5% to 10% of positive reactions prove due to cancer, however, so the large majority of reactive tests are false positives; this is an important weakness of occult blood screening. Slide hydration detects more tumors, but the predictive value of a positive test for cancer drops to only about 2%, which greatly diminishes the appeal of hydration. Sensitivity of occult blood tests for benign colonic polyps is poor, and most polyps found during workup of a positive reaction are actually detected by chance because of high prevalence in the general population. Controlled clinical trials have now documented that periodic occult blood screening produces a relatively small but significant mortality benefit from colorectal cancer--about 15% to 18% for biennial testing with unhydrated Hemoccult. Aggressive annual screening with hydrated Hemoccult may lower mortality by more than 30% but at a very high cost because of poor specificity and very low predictive value. Regular occult blood testing beginning at age 50 has been endorsed by many professional organizations because of the documented mortality benefit, but poor compliance, high costs, and ethical uncertainties seriously temper its justification. Whether to implement widespread occult blood screening remains a difficult societal decision.

Magnetic resonance cholangiopancreatography: a new technique for evaluating the biliary tract and pancreatic duct.

Year 1998
Fulcher AS. Turner MA. Zfass AM.
Department of Radiology, Medical College of Virginia Hospitals/Virginia Commonwealth University, Richmond 23298-0615, USA.
Magnetic resonance cholangiopancreatography (MRCP) represents a new development in MR technology that provides a noninvasive accurate means of evaluating the biliary tree and pancreatic duct. Recent technical refinements that allow for imaging of the entire biliary tree and pancreatic duct in 18 seconds make this examination easily performed even in critically ill patients. The clinical applications of MRCP are illustrated in a variety of scenarios that include choledocholithiasis, malignant obstruction, incomplete/failed endoscopic retrograde cholangiopancreatographies (ERCPs), postsurgical alterations of the biliary tract and gastrointestinal tract such as biliary-enteric anastomoses, intrahepatic bile duct pathology such as sclerosing cholangitis and AIDS cholangiopathy, chronic pancreatitis, congenital anomalies of the biliary tract and pancreatic duct, and gallbladder pathology.