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Diverticular Disease of the Colon

Acknowledgment The authors would like to acknowledge Drs. Benny Liu, Indhu Subramanian, and Robert Wong for their review and counsel during the development of this chapter. Historically, descriptions and investigations of diverticular disease of the colon are a relatively modern phenomenon. The French pathologist Jean Cruveilhier is widely credited with providing the first clear pathologic description in 1849: “…we not infrequently find between the bands of…

Appendicitis

Acknowledgment The author would like to acknowledge the significant contributions of Richard H. Turnage, MD, and Kfir Ben-David MD, to prior editions of this chapter. Historical Perspective Leonardo da Vinci was the first to describe the anatomic location of the appendix in the early 15th century, but it wasn’t until 1711 that the first clearly recognizable report of appendicitis was recorded by the German surgeon Lorenz…

Intestinal Ulcerations

Before the routine use of endoscopic imaging with capsule endoscopy (CE) and deep enteroscopy, discrete ulcers of the small and large intestine were thought to be rare but associated with a broad spectrum of diseases. Similarly, the classic literature on these ulcers has emphasized symptomatic presentations, typically of diseases not confined to the small or large intestine alone. Our current ability to image the small intestine…

Intestinal Ischemia

Acknowledgment We are indebted to Dr. Scott J. Boley, who worked for decades to lay the groundwork for this chapter and who played a critical role in preparing earlier editions. Intestinal ischemia produces a broad spectrum of disorders depending on the onset, duration, and cause of the injury; the area and length of bowel affected; the vessel involved; and the degree of collateral blood flow. Variability…

Ileostomies, Colostomies, Pouches, and Anastomoses

Total proctocolectomy with permanent end ileostomy is curative for patients with UC and returns most patients to excellent health while removing premalignant colonic mucosa in patients with UC or familial adenomatous polyposis (FAP). Improvements in surgical techniques and a better understanding of stoma physiology along with better stoma appliances and improved patient education have eliminated many of the dangers and disadvantages previously associated with an ileostomy.…

Management of Inflammatory Bowel Diseases

Historically, the goals of treatment of Crohn disease (CD) and UC have been achievement of symptomatic remission, namely absence of abdominal pain, diarrhea, or rectal bleeding and normalization of primarily symptom-based disease activity indices such as the CD activity index (CDAI) or simple clinical colitis activity index. Achieving these goals in the absence of corticosteroids, termed “steroid-free remission,” was recognized as sufficient to improve the patient’s…

Epidemiology, Pathogenesis, and Diagnosis of Inflammatory Bowel Diseases

IBD comprises conditions characterized by chronic or relapsing immune activation and inflammation within the GI tract. Crohn disease (CD) and UC are the 2 major forms of IBD; less common, but increasingly recognized, are the microscopic colitides, primarily collagenous colitis and lymphocytic colitis (see Chapter 128 ). Other chronic inflammatory conditions of the intestine share some features of presentation and pathogenesis with IBD, but they have…

Intestinal Worms

Parasitic worms are found worldwide, but intestinal colonization by helminths is most common in less industrialized, developing countries. Modern travel, emigration, and consumption of “exotic” cuisines allow intestinal helminths to appear in any locale. People now acquire tropical helminths without leaving their industrialized temperate cities. Because intestinal helminth infections are more frequent in developing countries, complete travel history is a critical—but often overlooked—aspect of the patient…

Intestinal Protozoa

Intestinal protozoa traditionally have been considered important pathogens in the developing world, where food and water hygiene are poor. A basic knowledge of the intestinal protozoa that cause human disease is of growing importance to physicians practicing medicine in the USA, Canada, and Europe, as a result of more frequent world travel, globalization of the world’s economy, and the growing number of chronically immunosuppressed people. For…

Antibiotic-Associated Diarrhea and Clostridioides difficile Infection

Antibiotic-Associated Diarrhea Etiology Diarrhea is a common adverse effect of antibiotic use and can result from a variety of mechanisms. The most common type of diarrhea, often simply called antibiotic-associated diarrhea (AAD), is not associated with any specific pathogen and is, in fact, not the result of infection; it is believed to be caused by a disturbance of the normal colonic microbiota that leads to alterations…

Food Poisoning

Food poisoning is defined as an illness caused by the consumption of food contaminated with bacteria, bacterial toxins, parasites, viruses, or chemicals. The percentage of outbreaks for which an etiology is confirmed has increased significantly from 40% in 1998 to 67% in 2002 and has remained consistent to the present. In a report from 2015, bacteria were responsible for 54% of foodborne outbreaks, whereas viruses accounted…

Infectious Enteritis and Proctocolitis

Infectious diarrhea is a major cause of illness throughout the world with 2.39 billion episodes of diarrhea estimated in 2015, of which 957.5 million occurred in children under the age of 5 years. Despite the number of deaths attributed to diarrhea declining by 20.8% from 2005 to 2015, over 1.3 million people die of diarrheal diseases each year worldwide with the greatest impact on infants and…

Whipple Disease

Whipple disease (WD) is a chronic systemic infection caused by a Gram-positive bacillus, Tropheryma whipplei . The small intestine is most commonly affected, but a variety of other organs may also be involved, including the joints, CNS, and heart. Clinical symptoms and findings are protean and include weight loss, diarrhea, malabsorption, fever, arthralgias, skin hyperpigmentation, and dementia. WD was considered to be uniformly fatal in the…

Tropical Diarrhea and Malabsorption

Diarrheal disease is common in tropical countries, affecting individuals of all ages and including indigenous residents as well as travelers to these countries. The frequency of diarrheal disease in warm tropical climates relates to multiple factors, including poor hygiene, poor sanitation, and the ability of the pathogens to survive and proliferate in food and water under such ambient conditions. In indigenous residents of the tropics, infection…

Celiac Disease

Acknowledgment The author gratefully acknowledges the important and valuable contributionsof the authors of previous editions, Drs. Ciaran P. Kelly, Jerry S.Trier, and Richard J. Farrell. Definitions Celiac disease is a chronic, immune-mediated enteropathy that is precipitated by dietary gluten in genetically predisposed individuals. Gluten is the commonly used term for the complex of water-insoluble proteins from wheat, rye, and barley that is harmful to patients with…

Short Bowel Syndrome

Short bowel syndrome (SBS) is characterized by malabsorption due to congenital absence or resection of large portions of the small intestine, typically leaving the adult with 150 to 200 cm of functional small bowel. Individuals with SBS have lost their nutritional autonomy and are left with an insufficient intestinal surface area such that they are unable to absorb adequate electrolytes, minerals, macro- and micronutrients, and/or fluid.…

Small Intestinal Bacterial Overgrowth

In its most simplistic form, the term SIBO describes a condition of excess bacteria in the small intestine. Although the phrase SIBO remains clinically relevant, it oversimplifies the rapidly evolving complexity of this disorder that has both intestinal and extra-intestinal manifestations. SIBO was first described in 1939 in patients with macrocytic anemia and intestinal strictures. Research studies on SIBO in the 1950s and 1960s focused on…

Maldigestion and Malabsorption

In the past, it was believed that most malabsorptive diseases manifested with diarrhea, steatorrhea, or both. It is now recognized that many malabsorptive disorders, such as celiac disease, might have subtle clinical presentations or mainly extraintestinal manifestations (e.g., anemia, bone loss, menstrual disturbance) that lead to a delayed and/or erroneous diagnosis. Awareness is also increasing that subtle malabsorption of single nutrients such as calcium or vitamin…

Digestion and Absorption of Micronutrients

The U.S. Department of Health and Human Services and the U.S. Department of Agriculture publish dietary guidelines for Americans every 5 years based on the most current evidence in nutrition science. These recommendations aim to promote health, prevent chronic disease and help individuals maintain a healthy weight. These guidelines also influence federal nutrition policies and product development. ( ). It is critical to remember, however,…

Digestion and Absorption of Carbohydrate, Protein, and Fat

Acknowledgments This work was supported by National Institutes of Health grant CA190710 and Welch Endowed Chair in Biochemistry, Grant No. BI-0028, at Texas Tech University Health Sciences Center. Digestion and absorption of dietary nutrients constitute the primary physiologic function of the GI tract; this includes not only the 3 major nutrients, namely carbohydrates, proteins, and fat, but also the micronutrients, (i.e., vitamins [water-soluble and lipid-soluble], electrolytes,…