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Category: Gastroenterology

WDHA Syndrome ?>

WDHA Syndrome

WDHA Syndrome Introduction Background In 1957, Priest and Alexander reported a patient with peptic ulcer, diarrhea, hypokalemia, and an islet cell tumor.1 However, the first complete description of the syndrome of watery diarrhea, hypokalemia, and achlorhydria (ie, WDHA syndrome) was provided by Verner and Morrison in 1958.2 This rare condition is characterized by severe watery diarrhea caused by oversecretion of vasoactive intestinal peptide (VIP) from non–beta pancreatic islet cells. Patients usually have elevated VIP levels and require frequent hospitalizations for…

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Zollinger-Ellison Syndrome ?>

Zollinger-Ellison Syndrome

Zollinger-Ellison Syndrome Introduction Background Zollinger-Ellison syndrome (ZES) is caused by a non–beta islet cell, gastrin-secreting tumor of the pancreas that stimulates the acid-secreting cells of the stomach to maximal activity, with consequent gastrointestinal mucosal ulceration. ZES may occur sporadically or as part of an autosomal dominant familial syndrome called multiple endocrine neoplasia type 1 (MEN 1). The primary tumor is usually located in the duodenum, the pancreas, and abdominal lymph nodes, but ectopic locations have also been described (eg, heart,…

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Hepatitis E ?>

Hepatitis E

Hepatitis E Introduction Background Hepatitis E virus (HEV) is an enterically transmitted infection that is typically self-limited. It is spread by fecally contaminated water within endemic areas. Outbreaks can be epidemic and individual. Hepatitis E has many similarities with hepatitis A. Hepatitis E infection has recently been associated with chronic hepatitis in solid organ-transplant recipients.1 

Hepatitis A ?>

Hepatitis A

Hepatitis A Introduction Background One of the more common causes of acute hepatitis is hepatitis A virus (HAV). The hepatitis A virus was isolated by Purcell in 1973. Since the application of accurate serologic investigations in the 1980s, the epidemiology, clinical manifestations, and natural history of hepatitis A have become apparent. The relative frequency of the hepatitis A virus as a cause of acute hepatitis has declined in Western societies, while in contrast, notification of individual cases has increased, primarily…

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Lactose Intolerance ?>

Lactose Intolerance

Lactose Intolerance Introduction Background Lactose intolerance is a common disorder and is due to the inability to digest lactose into its constituents, glucose and galactose, secondary to low levels of lactase enzyme in the brush border of the duodenum. Lactase deficiency is the most common form of disaccharidase deficiency. Enzyme levels are highest shortly after birth and decline with aging, despite a continued intake of lactose. Within the animal world, nonhuman mammals usually lose the ability to digest lactose as…

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Ileus ?>


Ileus Introduction Background After abdominal surgery, a normal physiological ileus occurs. This type of ileus spontaneously resolves within 2-3 days after sigmoid motility returns to normal. However, the terms postoperative adynamic ileus or paralytic ileus are defined as ileus of the gut persisting for more than 3 days following surgery.1 Ileus occurs from hypomotility of the gastrointestinal tract in the absence of a mechanical bowel obstruction. This suggests that the muscle of the bowel wall is transiently impaired and fails…

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Hiatal Hernia ?>

Hiatal Hernia

Hiatal Hernia Introduction Background A hiatal hernia occurs when a portion of the stomach prolapses through the diaphragmatic esophageal hiatus. Although the existence of hiatal hernia has been described in earlier medical literature, it has come under scrutiny only in the last century or so because of its association with gastroesophageal reflux disease (GERD) and its complications. By far, most hiatal hernias are asymptomatic and are discovered incidentally. On rare occasion, a life-threatening complication, such as gastric volvulus or strangulation,…

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Inflammatory Bowel Disease ?>

Inflammatory Bowel Disease

Inflammatory Bowel Disease Introduction Background Inflammatory bowel disease (IBD) is an idiopathic disease, probably involving an immune reaction of the body to its own intestinal tract. The 2 major types of IBD are ulcerative colitis and Crohn disease. As the name suggests, ulcerative colitis is limited to the colon; Crohn disease can involve any segment of the gastrointestinal tract from the mouth to the anus. Although ulcerative colitis and Crohn disease have significant differences, many (but not all) of the…

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Shigellosis ?>


Shigellosis Introduction Background Shigella organisms cause bacillary dysentery, a disease that has been described since early recorded history. Pathophysiology Shigella species (eg, Shigella dysenteriae, Shigella flexneri, Shigella sonnei, Shigella boydii) are aerobic, nonmotile, glucose-fermenting, gram-negative rods that are highly contagious, causing diarrhea after ingestion of as few as 180 organisms.

Villous Adenoma ?>

Villous Adenoma

Villous Adenoma Introduction Background Adenomatous polyps are, by definition, neoplastic. Although benign, they are the direct precursors of adenocarcinomas and follow a predictable cancerous temporal course unless interrupted by treatment. They can be either pedunculated or sessile. Polyps are generally asymptomatic but may occasionally ulcerate and bleed; uncommonly, they may result in obstruction if very large. Adenomas are divided into 3 subtypes based on histologic criteria, as follows: (1) tubular, (2) tubulovillous, and (3) villous. According to World Health Organization…

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