A wide variety of disorders can affect the pharynx and upper esophagus, such as inherited or acquired structural abnormalities, malignancies, and inflammation secondary to a number of etiologies including bacterial, yeast and viral infections, irradiation, and gastroesophageal reflux disorder. Laryngoceles and peritonsillar abscess can also lead to pain and dysfunction. However, this review will focus on the main motility disorders that affect the pharynx and upper esophagus, namely oropharyngeal dysphagia, disorders associated with globus pharyngeus, and Zenker’s diverticulum. Figures show the anatomy of the three stages of normal swallow, various findings on functional endoscopic evaluation of swallowing, electromyography of the cricopharyngeal sphincter and submental muscles, and Zenker’s diverticulum. Tables list causes of oropharyngeal dysphagia, neuromuscular control of the pharyngeal phase (with identified cranial and cervical spinal nerve roots), pathophysiology of oropharyngeal dysplasia, diagnostic tests for oropharyngeal dysplasia, behavioral treatments to improve swallow and reduce aspiration, and potential overlapping causes of impaired upper esophageal sphincter relaxation.

This review contains 4 highly rendered figures, 6 tables, and 40 references

Key words: Oropharyngeal dysphagia; Globus; Upper esophageal sphincter dysfunction; Swallowing disorder; Dysphagia; Zenker’s diverticulum; Swallow assessment; Globus pharyngeus

Eosinophilic esophagitis (EoE) is a chronic disorder characterized by eosinophil-predominant inflammation of the esophagus and clinical symptoms of esophageal dysfunction. It is believed to be immune/antigen-mediated, and its diagnosis requires recognition of specific clinical features with appropriate histologic findings on esophageal mucosal biopsies. Over the last 10 years, there has been an increase in the prevalence of EoE worldwide. A recent analysis estimated a prevalence of 56.7 per 100,000 persons, with males more often affected than females. This review covers the epidemiology, pathophysiology and pathogenesis, diagnosis, differential diagnosis, treatment, complications, and prognosis of EoE.

This review contains 3 figures, 2 tables, and 46 references.

Key words: dysphagia, eosinophilic esophagitis, eotaxin-3, esophageal dysfunction, esophageal eosinophilia, food impaction, inflammation of the esophagus 

Barrett esophagus is the condition in which normal stratified squamous epithelium of the esophagus is replaced by metaplastic columnar epithelium, which may predispose to development of malignancy. This metaplasia is thought to be a reparative mechanism to cope with reflex esophagitis induced by chronic gastroesophageal reflux disease. Barrett esophagus is associated with an increased risk of esophageal adenocarcinoma (EAC), although the more recent studies have shown that the risk of progression to malignancy is lower than was initially postulated. Endoscopic screening and surveillance are still warranted for early detection of dysplasia and neoplasia and prevention of EAC. This review looks at Barrett esophagus in detail, including its epidemiology and risk factors, etiology and pathogenesis, clinical presentation and symptoms, diagnosis, differential diagnosis, treatment, complications, and prognosis. Figures show images of Barret esophagus, endoscopic mucosal resection of nodule associated with Barrett esophagus, and focal radiofrequency ablation; a schematic of using Prague circumferential (C) and maximal extent (M) criteria to classify and report Barrett esophagus; and a proposed management algorithm for patients with Barrett esophagus. Tables list risk factors associated with Barrett esophagus and neoplastic progression to EAC, guidelines for screening and surveillance, and endoscopic eradication therapies. A list of useful Web sites relating to Barrett esophagus is also presented.

This review contains ­5 highly rendered figures, 3 tables, and 33 references. 

Gastroesophageal reflux disease (GERD) is the most common gastrointestinal diagnosis made in outpatient clinics, responsible for over 5 million annual outpatient visits and likely hundreds of thousands of inpatient stays for noncardiac chest pain. GERD’s current definition, based on international consensus, is a “condition which develops when the reflux of stomach contents causes troublesome symptoms (i.e., at least two heartburn episodes per week) and/or complications.” Also defining GERD is the presence of erosive esophagitis on upper endoscopy (esophagogastroduodenoscopy [EGD]) with or without the presence of troublesome symptoms or the presence of troublesome symptoms without endoscopic evidence of erosive esophagitis (also known as nonerosive reflux disease). This review looks at GERD in detail, including its epidemiology and risk factors, genetics, pathogenesis and etiologic factors, clinical presentation and symptoms, differentials, diagnosis, and complications. Figures presented are an EGD image showing signs of erosive esophagitis, Barrett esophagus, and hiatal hernia and sample recordings from a 24-hour combined multichannel intraluminal impedance and pH testing. Tables list differential diagnoses for GERD, indications for performing EGD in patients with GERD symptoms, and a summary of GERD therapies.

This review contains ­2 figures, 4 tables, and 74 references. 

Esophageal cancers are malignancies that can arise along the entire length of the esophagus, from the cervical inlet to the gastroesophageal junction (GEJ). The most common histologic types are adenocarcinoma and squamous cell carcinoma, which account for almost 95% of esophageal cancers. The location of esophageal cancer varies by histology and strongly influences its behavior and treatment approach. The esophagus is divided into four distinct anatomic regions: the cervical, upper thoracic, midthoracic, and lower thoracic esophagus. Squamous cancers usually occur in the upper or middle esophagus. Adenocarcinomas are more commonly found in the lower third of the esophagus and in the GEJ of the stomach. This review of esophageal cancer addresses the epidemiology, etiology/genetics, pathophysiology and pathogenesis, diagnosis, differential diagnosis, treatment, complications, and prognosis. Figures show Siewert classification, age-standardized esophageal cancer incidence rates by sex and world area, endoscopic images of esophageal tumors, chemotherapy for metastatic esophageal cancer, and a management algorithm for localized esophageal cancer. Tables list hereditary cancer syndromes associated with esophageal cancer, differential diagnosis of dysphagia, physical examination findings in esophageal cancer, differential diagnosis of esophageal lesions seen on endoscopy, and prognosis by stage at diagnosis.

This review contains 5 highly rendered figures, 5 tables, and 42 references.

Of patients who present with major gastrointestinal (GI) bleeding, 20 to 30% will ultimately be diagnosed with bleeding originating from a lower GI source. Lower GI bleeding has traditionally been defined as bleeding originating from a source distal to the ligament of Treitz; however, with the advent of capsule endoscopy and deep enteroscopy allowing for visualization of the entire small bowel, the definition has been updated to GI bleeding originating from a source distal to the ileocecal valve. Lower GI bleeding can range from occult blood loss to massive bleeding with hemodynamic instability and predominantly affects older individuals, with a mean age at presentation of 63 to 77 years. Comorbid illness, which is a risk factor for mortality from GI bleeding, is also more common with increasing age. Most deaths related to GI bleeding are not due to uncontrolled hemorrhage but exacerbation of underlying comorbidities or nosocomial complications. This review covers the following areas: evaluation of lower GI bleeding (including physical examination and diagnostic tests), initial management, and differential diagnosis. Disorders addressed in the differential diagnosis include diverticulosis, arteriovenous malformations (AVMs), ischemic colitis, anorectal disorders, radiation proctitis, postpolypectomy bleeding, and colorectal neoplasms. Figures show an algorithm for management of patients with suspected lower GI bleeding, tagged red blood cell scans, diverticular bleeding, colonic AVM, ischemic colitis, bleeding hemorrhoid, chronic radiation proctitis, and ileocolonic valve polyp. Tables list descriptive terms for rectal bleeding and suggested location of bleeding, imaging modalities and differential diagnosis for lower GI bleeding, endoscopic techniques for hemostasis, and an internal hemorrhoids grading system.

This review contains 9 figures, 8 tables, and 103 references.

Gastrointestinal (GI) bleeding that is proximal to the ligament of Treitz is considered upper GI bleeding (UGIB). UGIB can be further divided into variceal and nonvariceal, differentiated by etiology, presentation, management, and mortality. This review of nonvariceal UGIB addresses the epidemiology, diagnosis, treatment (including endoscopic therapy), prognosis, and differential diagnosis. Recommendations presented are evidence based and consistent with consensus statements and society guidelines. Figures show stigmata of recent hemorrhage, endoscopic therapy, peptic ulcer disease, Mallory-Weiss syndrome, angiodysplasia, Dieulafoy lesion, and arterioenteric fistula. Tables list the manifestation of GI bleeding and the presumed source of the bleeding, clues in the symptom and presentation of the patient that may suggest the diagnosis, medical history and physical examination findings that can suggest a specific diagnosis, a comparison of different prognostic scoring systems, differential diagnosis of UGIB, various etiologies of peptic ulcer disease, and treatment regimens for Helicobacter pylori.

This review contains 7 figures, 10 tables, and 85 references

Peptic ulcers are defects or breaks in the gastric or small intestinal mucosa that have depth and extend through the muscularis mucosae. The pathogenesis of peptic ulcers is multifactorial and arises from an imbalance of protective and aggressive factors such as when gastrointestinal mucosal defence mechanisms are impaired in the presence of gastric acid and pepsin. Infection with Helicobacter pylori and the use of nonsteroidal anti-inflammatory drugs and acetylsalicylic acid are major risk factors associated with peptic ulcers. In general, these factors disrupt normal mucosal defenses and repair, making the mucosa more susceptible to acid. This review covers the epidemiology of peptic ulcers, diagnostic tests for H. pylori, and treatment of peptic ulcers and H. pylori. The figure shows gastric biopsy samples stained with hematoxylin and eosin demonstrating chronic active gastritis both with and without the presence of H. pylori organisms. The tables list diagnostic tests for H pylori, and common treatment regimens for H. pylori.

Key words: Helicobacter pylori,H. pylori, NSAID-related peptic ulcer, diagnosis of helicobacter pylori, H. pylori treatment, urea breath test, ASA after bleeding ulcer

This review contains 1 highly rendered figure, 2 tables, and 54 references

The etiology of peptic ulcers is generally related to impaired mucosal defenses in the presence of aggressive factors (e.g., gastric acid and pepsin). Major risk factors include infection with Helicobacter pylori and the use of nonsteroidal antiinflammatory drugs; high rates of acid secretion can also predispose to ulcer formation. The prevalence of peptic ulcers in Western countries has declined since the 1950s, a phenomenon that is likely due to a corresponding decrease in H. pylori infections among the general population. This review summarizes the epidemiology, etiology, diagnosis, and treatment of peptic ulcers. Figures show the etiopathogenesis of peptic ulcers, the approach to a patient who has new and undiagnosed ulcerlike symptoms, and images of a gastrointestinal series in which double contrast (barium and air) was used, as well as an upright chest x-ray of a patient with an acute abdomen caused by a perforated duodenal ulcer. Tables list the differential diagnosis of peptic ulcer disease and commonly used regimens to eradicate H. pylori.

This review contains 3 highly rendered figures, 2 tables, and 35 references.

Functional dyspepsia(FD), formerly “nonulcer dyspepsia,” makes up approximately 50 to 75% of dyspepsia presentations. These presentations are defined by having no identifiable structural disease that would explain the symptoms. Recognizing the heterogeneity within the diagnosis of FD, the Rome III criteria further classify FD based on primary symptoms: postprandial distress syndrome and epigastric pain syndrome. The former term refers to bothersome fullness or early satiety with regular meals, whereas the latter is characterized by intermittent epigastric pain or burning that is not predictably meal associated. This review addresses FD, detailing the epidemiology, pathophysiology and pathogenesis, differential diagnosis, diagnosis, treatment, and prognosis. A figure shows the diagnostic algorithm for new-onset dyspepsia. Tables list the Rome III criteria for functional dyspepsia, alarm features in dyspepsia, and medications commonly associated with dyspepsia.

This review contains 1 highly rendered figure, 3 tables, and 27 references.

The gastric phase of digestion requires a tightly coordinated neuromuscular apparatus to permit appropriate timing for each step. Dysregulations in this apparatus may be related to the Cajal cells, the intrinsic enteric nervous system, the extrinsic nervous system, the muscle cells, or any combination of structures and may lead to abnormal gastric emptying, referred to as gastroparesis. Gastroparesis is idiopathic in 35 to 49.4% of cases but may also be related to diabetes, autoimmune and inflammatory conditions, multiple sclerosis, use of certain medications, and infections, among other factors. This review describes the epidemiology, etiology, pathophysiology, clinical manifestations, diagnosis, treatment, and prognosis of gastroparesis. The figure shows symptom mechanisms related to gastric physiology in gastroparesis patients. Tables list the physiopathologic mechanisms and symptoms associated with defective gastric physiologic phenomena, the classification of gastroparesis according to affected structures, and pharmacologic treatments for gastrointestinal dysmotility.

This review contains 1 highly rendered figure, 3 tables, and 56 references.

The main role of the small bowel is nutrient absorption; its mucosa lined with villi increases the contact surface between chyme and intestinal cells. Although the small bowel is the longest segment of the gastrointestinal (GI) tract, its transit takes between 2 and 5 hours and is the shortest of the whole gut. It is the most resilient segment of the GI tract and is thus rarely affected by motility disorders. Small bowel dysmotilities comprise a group of rare disorders affecting the function of any structure of the contractile apparatus from the muscular cells, the intrinsic neurons, or the extrinsic neurons. This review covers the epidemiology, etiology, differential diagnosis, clinical manifestations, physical examination, diagnosis, and treatment of small bowel dysmotilities and bacterial overgrowth. The figure shows GI tract innervations and related pharmacologic treatments. Tables list etiologies of small bowel dysmotilities categorized as primary or secondary causes, treatment strategies related to physiologic abnormalities, and pharmacologic treatments for GI dysmotilities.

Key words: chronic intestinal pseudo-obstruction, gastrointestinal dysmotility, motility disorder, small bowel dysmotility, small intestinal bacterial overgrowth

This review contains 1 highly rendered figure, 3 tables, and 51 references.

Irritable bowel syndrome (IBS) is characterized by recurrent abdominal pain or discomfort that has occurred at least 3 days per month in the 3 months prior to diagnosis. One of the subtypes of this disorder is IBS with constipation (IBS-C), where individuals experience hard or lumpy stools at least 25% of the time and loose or watery stools less than 25% of the time with defecation. This review addresses IBS-C, detailing the epidemiology, etiology, pathophysiology and pathogenesis, diagnosis, differential diagnosis, treatment, and prognosis. A figure shows the Bristol stool form scale. Tables list IBS subtypes, components of digital rectal examination, differential diagnoses for IBS and IBS-C, alarm features, and the American College of Gastroenterology Recommendations.

This review contains 1 highly rendered figure, 6 tables, and 71 references. 

Irritable bowel syndrome (IBS) is a complex, functional gastrointestinal condition characterized by abdominal pain and alteration in bowel habits without an organic cause. One of the subcategories of this disorder is IBS with diarrhea (IBS-D). Clinically, patients who present with more than 3 months of abdominal pain or discomfort associated with an increase in stool frequency and/or loose stool form are defined as having IBS-D. This review addresses IBS-D, detailing the epidemiology, etiology and genetics, pathophysiology and pathogenesis, diagnosis, clinical manifestations and physical examination findings, differential diagnosis, treatment, emerging therapies, complications, and prognosis. Figures show potential mechanisms and pathophysiology of IBS, IBS-D suspected by clinical assessment and Rome III criteria, pharmacologic and nonpharmacologic treatment options, potential mechanisms of action of probiotics, and potential treatment modalities. Tables list the Rome criteria for IBS, alarm signs and symptoms suggestive of alternative diagnoses, IBS criteria, differential diagnosis of IBS-D, dietary advice options for IBS-D, and alternative and emerging therapies in IBS-D.

This review contains 5 figures, 6 tables and 42 references

KEYWORDS: IBS-D, eluxadoline, rifaximin, probiotics, bloating, antidepressants, bile acid malabsorption, microscopic colitis, celiac

Celiac disease, often also termed celiac sprue, is an immune-mediated disorder triggered by ingestion of wheat, barley, rye, and triticale gluten proteins in genetically predisposed individuals. The offending glutens induce a characteristic but variable and nonspecific lesion of the small intestinal mucosa that improves following gluten withdrawal. Patients with refractory celiac disease (RCD) have persistent or recurrent symptomatic malabsorption together with biopsy-documented enteropathy that has not responded to 6 to 12 months of strict gluten withdrawal. Tropical sprue is an illness that occurs in individuals living in tropical countries; clinical features include anorexia, diarrhea, and intestinal malabsorption, leading to weight loss accompanied by a characteristic although nonspecific lesion of the mucosa of the small
intestine. This review addresses the epidemiology, etiology/genetics, pathophysiology and pathogenesis, diagnosis, differential diagnosis, treatment, complications, and prognosis of these related diseases. Figures show the celiac disease iceberg, duodenal mucosal surface seen at endoscopy, duodenal mucosal biopsies from a patient with celiac disease, higher magnification micrograph of the duodenal mucosal surface from a patient with untreated celiac disease, duodenal biopsies from a patient with refractory celiac disease, and duodenal biopsy obtained from an Indian expatriate with diarrhea, weight loss, and folate deficiency. Tables list selected extraintestinal manifestations of celiac disease, prevalence of celiac disease in selected conditions, disorders with duodenal lesions that may mimic those of celiac diseases, initial treatment for celiac disease, organizations that provide helpful information for gluten-intolerant patients, considerations in a patient not responding to a gluten-free diet, and features that help distinguish tropical sprue from celiac disease.

This review contains 6 highly rendered figures, 7 tables, and 96 references. 

Eosinophilic gastroenteritis (EG) is a rare condition characterized by eosinophilic infiltration of the gastrointestinal (GI) tract. This review addresses the epidemiology, etiology and genetics, pathophysiology and pathogenesis, diagnosis, differential diagnosis, treatment, complications, and prognosis of EG. A figure shows the histologic appearance of stomach and duodenal mucosa in patients with EG. Tables list symptoms of EG and differential diagnosis.

This review contains 1 highly rendered figure, 2 tables, and 27 references. 

Short bowel syndrome (SBS) is a state of malabsorption resulting from physical or functional loss of large portions of the small intestine, and is the most common cause of intestinal failure. The average length of a human’s small intestine is between 3 and 8 m, depending on the type of measurements made (surgical, radiologic, or autopsy); SBS occurs when less than 200 cm of small bowel remains. SBS may be congenital (intestinal atresia) or acquired. Physical losses usually occur from surgical resection for Crohn disease (CD), vascular insufficiency, radiation, malignancy, trauma, or volvulus. The site of intestinal resection helps to determine the degree of intestinal capacity. Functional losses, on the other hand, are less common and occur in the setting of a nonfunctioning, but intact, small intestine. Examples include radiation enteritis, congenital defects, and inflammatory bowel disease (IBD). This review addresses the epidemiology, pathophysiology and pathogenesis, clinical manifestations, treatment, complications, and prognosis of SBS. A figure shows sites of intestinal nutrient absorption. A table lists potential complications of SBS in patients receiving parenteral nutrition (PN).

This review contains 1 highly rendered figure, 1 table, and 67 references. 

Systemic mastocytosis (SM) is a disease characterized by an abnormal proliferation and accumulation of a clonal population of mast cells in the tissues including the bone marrow, gastrointestinal tract, and skin. In the most common form, indolent mastocytosis, the symptoms are most often due to the consequences of mast cell activation and include flushing, abdominal pain, and diarrhea. The diagnosis is made using a defined set of criteria based on a tissue biopsy, with special staining and a blood test for tryptase. Treatment is directed at the mast cell activation and specific symptoms such as nausea and abdominal bloating. Differential diagnosis includes the non-clonal form of mast cell activation syndrome and IgE-mediated allergy.

Keywords: mast cell, mast cell activation, mastocytosis, tryptase, flushing, urticaria pigmentosa, dermatographism

This review contains 5 highly rendered figures, 4 tables, and 35 references.

Celiac disease (CD) is an autoimmune disorder characterized by an immune response to gluten peptides in wheat, barley, and rye. The diagnosis of celiac disease is confirmed by three important characteristics: consistent symptoms, positive celiac-specific serology, and small intestinal biopsy findings of inflammation, crypt hyperplasia, and villous atrophy. CD may present with overt gastrointestinal symptoms, including diarrhea (or constipation), weight loss, and abdominal bloating and discomfort, or covertly with micronutrient deficiencies such as iron deficiency with anemia. A gluten-free diet (GFD) remains the mainstay of treatment. The aim of this review is to highlight the pathogenesis of CD, concepts and challenges associated with a GFD, and nutritional management of CD applicable in clinical practice to internists, gastroenterologists, and dietitians. Patients should be referred to an expert celiac dietitian for education on adherence to a GFD to address gluten contamination in the diet, the psychosocial implications of following a GFD, and macro- and micronutrient disequilibria arising from celiac disease and the GFD. Several novel therapeutics are on the horizon in various stages of development, including glutenases, antigliadin antibodies, tight junction regulators, modulation of the immune response to gliadin, and efforts to engineer less toxic gluten-containing foodstuffs.

This review contains 3 figures, 5 tables, and 61 references.

Key words: celiac disease, genetic engineering, food engineering, gluten, glutenases, gluten-free diet, oats, IgY, nutrition, tight junction regulators, wheat

Inflammatory bowel disease (IBD) comprises chronic disorders characterized by inflammation of the gastrointestinal tract. The two major identified subtypes of IBD are ulcerative colitis (UC) and Crohn disease (CD), and over many years, each can demonstrate periods of recurrence and remission. Although the presentation and clinical patterns of UC and CD have been well studied, many questions remain regarding the underlying disease pathogenesis. On an individual level, the development of clinically active IBD appears to occur on account of a complex set of interactions of distinct risk factors, including genetic predisposition, environmental exposures, and geographic location. On a global scale, the highest rates of IBD are found in Europe and North America, with worldwide prevalence of UC and CD increasing. Figures show the prevalence of UC and CD in the United States, stratified by region. Tables show the prevalence of IBD in North America as identified by various studies and environmental risk factors for inflammatory bowel disease.

This review contains 2 highly rendered figures, 2 tables, and 134 references. 

The study of the pathogenesis of IBD has advanced tremendously in recent years, coinciding with novel scientific experimentation and computational analysis tools. Crohn disease (CD) and ulcerative colitis (UC) are the two major types, characterized by chronic relapsing and remitting intestinal inflammation, and their respective pathophysiologies are the focus of this review. Also examined are the genetic influences, environmental influences, immune defects, and clinical implications associated with IBD. Figures include presentations of UC and CD, the multidirectional relationship causing the pathogenesis of IBD, and functional programs identified through genetic associations in IBD. Table lists the current therapeutic strategies in IBD based on target.

This review contains 3 highly rendered figures, 1 table, and 131 references.

Idiopathic inflammatory bowel disease (IBD) encompasses two major types: ulcerative colitis (UC) and Crohn disease (CD). The pathologic features of UC are typically restricted to the mucosa and superficial submucosa, whereas CD is characterized by patchy, segmental, mucosal, and mural inflammation. This review covers the classic pathologic features of IBD, differential diagnosis, dysplasia in IBD, and practical guidelines for clinicians who perform surveillance endoscopy. Figures show gross specimens of UC and CD variations and low- and high-grade dysplasia. Tables list the microscopic features of untreated UC and CD, the most common causes of uncertainty in IBD pathology that lead to a diagnosis of indeterminate colitis, a summary of inflammatory disorders of the colon that may mimic UC or CD on biopsy or resection, and diseases that can occur in patients with established UC or CD and result in changes to the type, pattern, and severity of inflammation.

This review contains 5 highly rendered figures, 4 tables, and 75 references. 

Inflammatory bowel disease (IBD) is composed of two major subtypes, ulcerative colitis (UC) and Crohn disease (CD). These chronic disorders, characterized by inflammation of the gastrointestinal tract, demonstrate a variety of clinical features, including intestinal and extraintestinal manifestations during periods of relapse and remission over many years. This review examines the clinical features of IBD, including the extraintestinal manifestations and diagnosis. Figures include examples of images conducted via computed tomography (CT), magnetic resonance imaging, and position emission tomography (PET)/CT. Tables list the location frequencies of UC and CD at the time of diagnosis, extraintestinal manifestations of IBD, differential diagnosis of UC and CD, and clinical utility of fecal calprotectin in the evaluation and management of IBD.

This review contains 4 highly rendered figures, 5 tables, and 48 references. 

Inflammatory bowel diseases (IBDs) are a group of chronic inflammatory disorders that are mainly represented by Crohn disease and ulcerative colitis. Over the last decade, conventional fluoroscopic barium studies used for the imaging of the gastrointestinal tract have been replaced with newer techniques, such as multidetector-row computed tomography (CT), dual-energy CT, and positron emission tomography (PET)/CT. Also increasingly seen is the use of magnetic resonance enterography, representing a robust, highly accurate, and radiation-free imaging method. This review covers these newer imaging modalities for IBD and more, as well as proposed techniques that could potentially help monitor and guide new antiinflammatory treatment strategies in the future. Figures include examples of images conducted via CT, magnetic resonance imaging, and PET/CT. Table compares different imaging modalities for the evaluation of IBD.

This review contains 13 highly rendered figures, 1 table, and 127 references. 

Crohn disease (CD) is an inflammatory condition that can affect any portion of the gastrointestinal tract from the mouth to the perianal area. The resulting transmural inflammation can lead to a spectrum of clinical presentations depending on disease location and severity. The treatment of CD depends on the severity of the disease, phenotype, presence of perianal disease, and response to previous therapies. This review examines the goals of therapy for CD, clinical symptoms and disease activity, treatment of disease based on mild to moderate to severe stages, treatment of refractory disease, perianal disease, postoperative CD, and noninflammatory treatment options. Figures show adalimumab injection-site reaction and perianal fistula with seton placement. Tables list the Crohn Disease Activity Index (CDAI), the Harvey Bradshaw Index, 5-aminosalicylic acid formulations, standard dosing of CD medications for moderate to severe disease, and rates of clinical response and remission in patients receiving anti–tumor necrosis factor agents versus placebo, by trial.

This review contains 2 highly rendered figures, 5 tables, and 85 references. 

Ulcerative colitis (UC) is a chronic idiopathic inflammatory bowel disease (IBD) characterized by continuous colonic mucosal inflammation that extends proximally from the rectum. Most patients present with bloody diarrhea, abdominal pain, tenesmus, and urgency. The course of UC is characterized by periods of flares and remission, and can significantly impact quality of life. Most patients are successfully treated medically, though 15 to 25% of patients require total proctocolectomy.Treatment of UC depends on the extent and severity of the disease, and response to prior therapies. This review outlines the medical treatment of UC and the therapies available for the induction and maintenance of remission. Figures include endoscopic and histologic images of UC, and algorithms cover outpatient inductions for mild-to-moderate disease and moderate-to-severe-disease, outpatient management of known steroid-refractory/steroid-intolerant patient, and approach to inpatient management of acute severe UC. Tables list disease severity by Truelove and Witts criteria, IBD medication adverse effects and monitoring parameters, induction dosing of 5-aminosalicylates, and rates of clinical response, remission, and mucosal healing in patients receiving anti-tumor necrosis factor (TNF) agents versus placebo by trial.

This review contains 5 highly rendered figures, 4 tables, and 118 references. 

The extraintestinal manifestations (EIMs) of inflammatory bowel disease (IBD) can be classified as the following: (a) true EIMs due to reactive IBD affecting organ systems, (b) complications secondary to IBD activity, (c) non–IBD-specific autoimmune disease which occurs in increased frequency in individuals with IBD. Overlap is frequent between EIMs and extraintestinal complications, and it is increasingly evident that multiple organ systems may be involved. This review covers EIMs through their epidemiology, etiology/genetics/pathogenesis, prognosis, complications, and treatment. Also detailed are the organ systems involved with reactive IBD, including musculoskeletal, pulmonary, dermatological, ophthalmic, and hepatobiliary manifestations. Figures show the classification, etiology, and pathogenesis of EIMs of IBD, musculoskeletal and pulmonary manifestations of IBD, metastatic Crohn disease of the intergluteal cleft, pyoderma gangrenosum, oral apthous ulcers, Sweet syndrome, leucocytoclastic vasculitis, anti-tumor necrosis factor–induced psoriasis, uveitis, episcleritis, and primary sclerosing cholangitis. Tables list the modified New York criteria for ankylosing spondylitis, pulmonary manifestations of IBD and IBD-related treatment, diagnostic techniques in lung disorders associated with IBD, dermatologic manifestations of IBD based on classifications, specific cutaneous manifestations or granulomatous cutaneous lesions with the same histological features as the underlying bowel disease, reactive cutaneous manifestation of IBD with immunological mechanisms triggered by common antigens shared by gut bacteria and skin, cutaneous disorders or dermatosis associated with IBD, secondary cutaneous manifestations due to complications of IBD and adverse effects of IBD treatment, treatment of dermatological manifestations of IBD, diagnosis of ophthalmological manifestations of IBD, and other hepatobiliary manifestations of IBD. 

This review contains 13 highly rendered figures, 12 tables, and 79 references. 

Inflammatory bowel diseases (IBDs) commonly affect women in their reproductive years; 25% of women with IBD become pregnant after the diagnosis. The relation of IBD to reproductive function often manifests in issues concerning fertility, antepartum pregnancy management, mode of delivery, and lactation as these can be influenced by disease activity, medications, perianal disease, and previous ileoanal pouch surgery. As disease location, activity, and complications can vary between patients, an individualized approach with multidisciplinary management is recommended. Pregnancy outcomes, recommended medication, nursing, managing IBD flares during pregnancy, and immune pathways are also discussed. Figures show issues discussed in preconception counseling and pregnancy guidelines. Tables list medication recommendations, Food and Drug Administration categories for the use of medications in pregnancy, adverse pregnancy outcomes PIANO registry, pregnancy and biological recommendations, thiopurine recommendations, safety of biologics in pregnancy, biologic guidelines, and sick pregnant patient recommendations.

This review contains 2 highly rendered figures, 8 tables, and 29 references. 

Colorectal cancer (CRC) is the third most common and lethal cancer in men and women in the United States. At presentation, a significant proportion of patients with CRC are able to undergo resection with curative intent, but up to 50% of these patients will develop recurrent disease. Fortunately, recurrence rates for both colon and rectal cancer have improved with the introduction of multimodality therapies, which include chemotherapy, chemoradiation therapy, and radiation therapy. These therapies are adjuncts to surgery and can be administered before (i.e. neoadjuvant) or after (i.e. adjuvant) surgery. This review summarizes the current evidence for the use of adjuvant and neoadjuvant therapies in colon and rectal cancer.

This review contains 2 figures, 7 tables, and 77 references.

Keywords: Colon cancer, rectal cancer, neoadjuvant therapy, adjuvant therapy, total neoadjuvant therapy, induction chemotherapy in rectal cancer, chemoradiation, organ preservation, non-operative management

Microscopic colitis (MC) is defined by the presence of specific histologic abnormalities in patients with diarrhea and a normal-appearing colon at endoscopy. MC can be categorized into two types: collagenous colitis (CC) and lymphocytic colitis (LC). CC is characterized by a thickened subepithelial collagen band in the colonic mucosa of at least 10 mm in thickness, whereas LC describes infiltration of the colonic epithelium with lymphocytes (intraepithelial lymphocytes), without excess collagen in the mucosa. This review of MC addresses the epidemiology, pathogenesis, etiology/genetics, diagnosis, differential diagnosis, treatment, complications, and prognosis between the two types. Tables list potential etiologic factors in MC, medications associated with MC, and treatments used for MC and evidence base.

This review contains 3 tables and 55 references.

Inflammatory bowel disease is a chronic inflammatory disease of the intestine that can be divided into two main categories: Crohn disease and chronic ulcerative colitis (CUC). Although the role of medical therapy in CUC is directed at symptom control or the underlying inflammatory process, fortunately, the intestinal manifestations of CUC can be effectively cured by surgery. The operation of choice is an ileal pouch-anal anastomosis (IPAA), which can be performed open or laparoscopically, with a hand-sewn or stapled anastomosis, or in a one-, two-, or three-stage fashion. Although pouch function and quality of life remain good following IPAA, common complications include pouchitis, anal stricture, pouch fistulas, and small bowel obstructions. The most dreaded complication is an anastomotic leak resulting in pelvic sepsis and, often, eventual pouch excision. Less common complications include pouch dysplasia or cancer and de novo Crohn disease of the pouch. Overall, regardless of age, patient satisfaction following IPAA remains high, and more than 90% of patients retain their pouches for more than 20 years. 

This review contains 11 figures, 4 tables and 85 references

Keywords: Inflammatory bowel disease, ulcerative colitis, laparoscopy, ileal pouch-anal anastomosis, pouchitis

Recurrent fistulas, fistulas with multiple external openings, those involving more than one third of the anal sphincter complex, and fistulas involving adjacent organs are considered complex. Fistulas occurring in the setting of perianal Crohn disease or following pelvic radiation are also considered complex. Evaluation of a fistula includes a detailed history and physical examination. Imaging with ultrasonography helps delineate the course of a fistula relative to adjacent structures as well as identify occult branching of the fistula tract. The initial step in treating fistulas is resolving associated inflammation. When treating fistulas with multiple branching tracts, the portion of the tracts outside the anal sphincter complex should be unroofed, with the goal of transforming the complex fistula into a simpler fistula with a single internal opening. The selection of the most appropriate treatment for a complex fistula depends on the etiology, anatomy, patient comorbidities, and condition of surrounding tissue.

Key Words: anal fistula, anovaginal fistula, Crohn disease, fistulotomy, rectourethral fistula

Acute pancreatitis (AP) is defined as the presence of two of the following findings: (1) upper abdominal pain; (2) serum amylase or lipase greater than three times the upper limit of normal; and/or (3) characteristic findings of AP on abdominal imaging (contrast-enhanced computed tomography, magnetic resonance imaging, or abdominal ultrasonography). This review addresses AP, detailing the subclassification, epidemiology, pathophysiology, etiology, diagnosis and differential diagnosis, treatment, complications, and prognosis. Figures include abdominal imaging of patients with AP, an algorithm depicting pancreatic collections, and an endoscopic image of the gastric portion of the cystogastrostomy. Tables list systemic inflammatory response syndrome; classification of the severity of AP; etiologies of AP, gallstones, biliary sludge, microlithiasis, and crystals; secondary causes of hypertriglyceridemia; common drugs and drug classes associated with AP; conditions mimicking AP; diagnostic criteria for infected necrosis; and prognostic scoring systems for AP.

This review contains 3 highly rendered figures, 9 tables, and 182 references. 

Pancreatitis is a complex spectrum of disease including chronic pancreatitis, acute pancreatitis, and manifestations of severe acute pancreatitis such as sterile and infected necrotizing pancreatitis. Acute pancreatitis is the leading cause of hospitalization for gastrointestinal disorders in the United States. Pancreatitis is a dynamic condition, and severity may change and evolve during the course of the disease. Although most patients with acute pancreatitis have mild disease, 10 to 15% will run a fulminant course, leading to severe acute pancreatitis, pancreatic necrosis, and multisystem organ injury. The mortality for severe acute pancreatitis is 15 to 30%; however, the overall mortality for all patients with acute pancreatitis is less than 5%. Early management of acute pancreatitis includes fluid resuscitation, pain control, and enteral nutrition. There are no specific directed therapies proven to be effective for the early treatment of acute necrotizing pancreatitis; therapy is entirely supportive. Chronic pancreatitis is a challenging disease often marked by chronic pain. Surgical intervention may help improve quality of life and relieve pain in selected patients. International consensus guidelines provide definitions and classifications to aid clinicians with diagnosis and management of pancreatitis. This review covers advances related to pancreatitis, including literature pertaining to the step-up approach for necrotizing pancreatitis first published in 2010, discussion of the revised Atlanta Classification System for severity of acute pancreatitis published in 2013, review of the current spectrum of microbial pathogens implicated in infected necrotizing pancreatitis, and the international draft consensus proposal for a new mechanistic definition for chronic pancreatitis published in 2016.

This review contains 5 figures, 11 tables and 62 references

Keywords: acute pancreatitis, antibiotic prophylaxis, Atlanta Classification System, biliary pancreatitis, chronic pancreatitis, necrosectomy, pancreatic necrosis, pancreatitis, step-up approach, video-assisted retroperitoneal drainage (VARD)

Chronic pancreatitis (CP) is a syndrome that is characterized by inflammation, irreversible fibrosis, and loss of acinar and islet cells. It has also been described as an “enigmatic process of uncertain pathogenesis, unpredictable clinical course, and unclear treatment.” This review describes the epidemiology, diagnosis, diagnostic challenges, differential diagnosis, treatment, complications, and clinical course and prognosis of CP, as well as future challenges. Figures show a computed tomographic (CT) scan of calcific CP, a secretin-enhanced magnetic resonance cholangiopancreatogram showing a dilated and tortuous main pancreatic duct, a CT scan of a large chronic pseudocyst compressing the stomach and pancreas, an endoscopic ultrasound (EUS) image of CP, a retrograde pancreatogram showing a dilated main pancreatic duct with stones and “blunted” side branches, sources of pain in CP, neuropathic pain mechanisms in CP, and an algorithm summarizing treatment of pain in CP. Tables list the TIGAR-O etiologic classification of CP, standard criteria for diagnosis of CP by EUS, Cambridge endoscopic retrograde cholangiopancreatography grading for CP, and a stepwise radiographic and endoscopic diagnostic approach to patients with suspected CP.

Key words: bile duct obstruction, chronic pancreatitis, pancreatic calcifications, TIGAR-O system

This review contains 8 highly rendered figures, 4 tables, and 54 references.

Autoimmune pancreatitis (AIP) is a subcategory of chronic pancreatitis that is highly responsive to steroids. The term was first proposed in 1995 by Yoshida and colleagues, and since its discovery, the diagnosis of AIP has dramatically increased. AIP is a chronic fibroinflammatory disease characterized by lymphoplasmacytic infiltrates and fibrosis on histology. There are two distinct subtypes: type 1 AIP is the pancreatic manifestation of a systemic serum immunoglobulin G subtype 4–related disease (IgG4-RD) and type 2 AIP is described clinically as idiopathic duct-centric pancreatitis and has no association with IgG4. Clinically, AIP presents most commonly as obstructive jaundice in type 1 AIP and can present as acute pancreatitis in type 2 AIP. The diagnostic criteria include histology, imaging findings, and responsiveness to steroids as well as laboratory findings and other organ involvement. The mainstay of treatment is steroid therapy, with immunomodulators such as rituximab used for maintenance or relapsing disease. Long-term complications of AIP include pancreatic insufficiency and are often associated with relapsing disease.

This review contains 45 references, 1 figure, and 2 tables.

Key Words: autoimmune pancreatitis, chronic pancreatitis, EUS-guided biopsy, IgG4, immunomodulatory, obstructive jaundice, pancreas mass, steroid

Pancreatic cancer is among the most aggressive human cancers, with few symptoms and clinical findings until it is detected in an advanced stage. Today, the only favorable treatment is surgical resection before progression to an invasive stage. There are a variety of benign and premalignant conditions of the pancreas that may appear similar to malignant tumors; early detection and management of those premalignant pancreatic lesions may provide a significant improvement in patient outcome. This review covers cystic neoplasms of the pancreas, premalignant solid lesions of the pancreas, and inflammatory lesions of the pancreas. Figures show a 30 mm diameter hypoechoic lesion without septae in the pancreatic head, an oval 20 mm diameter pancreatic mass with mixed solid and cystic components, a 24 mm diameter hypoechoic mass with well-defined borders in the tail of the pancreas, a 22 × 18 mm cystic lesion with a thick wall and internal debris in the head of the pancreas, and an endoscopic cyst gastrostomy after balloon dilation. Tables list World Health Organization (WHO) 2010 classification of pancreatic tumors, classification of pancreatic cystic lesions, main characteristics of common pancreatic cystic lesions, high-risk stigmata and worrisome features of intraductal papillary mucinous neoplasm on cross-sectional imaging, and WHO classification of pancreatic neuroendocrine tumors.

This review contains 5 highly rendered figures, 5 tables and 55 references

Malignant lesions of pancreas are the fourth most common cause of cancer death in men and women. The majority of pancreatic cancer results from malignant transformation of the exocrine pancreas, and nearly 90% are ductal adenocarcinomas (pancreatic ductal adenocarcinoma, PDAC). Patients typically present at an advanced stage with a poor prognosis. PDAC is acquired through the accumulation of multiple genetic mutations. The major risk factors for PDAC include age, smoking, chronic pancreatitis, diabetes mellitus (DM), male gender, and African American race. Less commonly, hereditary syndromes may be implicated. The clinical presentation may involve weight loss, abdominal discomfort, and or jaundice. Painless jaundice, depression, and new-onset DM can suggest the diagnosis. Cross-sectional imaging has utility in diagnosis and staging. Endoscopic ultrasound (EUS) with fine needle aspiration (FNA) is a standard approach to tissue diagnosis. Endoscopic retrograde cholangiopancreaticography with palliative stenting can relieve obstructive jaundice. Surgical resection is the only potentially curative option in the management of PDAC but only a minority of patients are candidates for resection. The prognosis for most patients with pancreatic adenocarcinoma is poor. Less common pancreatic malignant lesions such as neuroendocrine tumors (NETs) have a much more favorable prognosis.

Key words: Pancreatic cancer; Pancreatic ductal adenocarcinoma; Pancreatic NETs (PNETs); Pancreatic neuroendocrine tumors

Gallstone disease (cholelithiasis), very common in the United States, afflicts around 15% of the adult population and accounts for approximately 1.8 million ambulatory visits per year. Elective laparoscopic cholecystectomy for the removal of gallstones is currently the most commonly performed abdominal operation in the United States, with around 750,000 operations per year. Although the majority of patients with asymptomatic gallstones will never develop symptoms, approximately 25% of these initially asymptomatic patients will develop biliary pain and 3% will develop complications over a 10-year follow-up period. This review discusses the pertinent pathophysiology and treatment of gallstones and their complications. It is imperative for the primary care physician, gastroenterologist, and surgeon to rapidly identify those patients at risk for complications of gallstone disease and offer the best evidence-based therapies available. It is also important for the physician to understand when and if to offer treatment for those patients with asymptomatic gallstone disease. Figures show the mixed micelle, the anatomy of gallstones, radial endoscopic sonogram of a gallstone in common bile duct (CBD), an algorithm depicting the risk of CBD stone in patients with known cholelithiasis, and endoscopic retrograde cholangiography images of a large gallstone within CBD and stone fragments in duodenum following lithotripsy and extraction. Tables list risk factors for gallstone formation, common medications associated with gallstone formation, and uncommon complications of gallstone disease.

This review contains 5 highly rendered figures, 3 tables, and 53 references. 

Primary sclerosing cholangitis (PSC) is a chronic progressive cholestatic disease characterized by inflammation and fibrosis that may involve the entire biliary tree. The fibrosis causes diffuse narrowing of the intrahepatic and extrahepatic bile ducts, and the resulting biliary stasis leads to secondary biliary cirrhosis and associated complications. This review addresses PSC through its epidemiology, etiopathogenesis, diagnosis, differential diagnosis, management, complications, and prognosis. Figures show pouchoscopy, liver biopsy, and endoscopic retrograde cholangiopancreatography; direct peroral cholangioscopy visualization of cholangiocarcinoma; and algorithms depicting diagnosis of cholangiocarcinoma and screening for inflammatory bowel disease (IBD) in patients with PSC. Tables list characteristics of IBD in PSC, prevalence of antibodies in PSC, differential diagnosis of PSC, diagnostic approach in PSC, and risk of cancers in PSC.

This review contains 6 highly rendered figures, 5 tables, and 91 references. 

Cholelithiasis is extremely common in the United States, affecting approximately 10 to 15% of the population. The vast majority of patients remain asymptomatic. Elective cholecystectomy for symptomatic cholelithiasis is a well-established procedure with excellent outcomes. The diagnosis in critically ill patients may not be straightforward. Inflammation and infection of the gallbladder can lead to significant morbidity and mortality. Whether the gallbladder is the primary etiology of hemodynamic compromise (as in emphysematous or gangrenous cholecystitis) or is the victim of secondary insult (as in ischemia-related acalculous cholecystitis), the intensivist must consider cholecystitis in the differential of clinical deterioration.

This review contains 6 figures, 5 tables, and 59 references.

Key words: acalculous, biliary disease, cholangitis, cholecystitis, emphysematous cholecystitis

Diverticular disease has been considered a disease of the elderly, but recently, an increased incidence has been noted in younger patients. Diverticulosis is asymptomatic; however, when symptomatic, it is referred to as diverticular disease. When associated with any inflammation, it is diverticulitis. Diverticulitis is an acute illness, but symptoms may become chronic with recurrent episodes. When mucosal inflammation is present, segmental colitis associated with diverticula (SCAD) is identified. SCAD is a distinct, but uncommon, disorder sharing histological and clinical features of ulcerative colitis and Crohn disease. Only 1 to 2% of patients with diverticulosis will develop diverticulitis. This review covers the epidemiology, etiology and genetics, pathophysiology and pathogenesis, diagnosis, management, complications and prognosis of diverticulosis, and diverticulitis. Figures show diverticulosis, symptomatic uncomplicated diverticular disease, diverticulitis, computed tomography scan of acute diverticulitis, and a management algorithm. Tables list definitions, risk factors, pathophysiology, modified Hinchey classification, and acute diverticulitis differential diagnosis.

This review contains 5 highly rendered figures, 5 tables and 105 references

Colorectal cancer (CRC) is the second most common cancer in women and the third most common in men and is the third leading cause of all cancer deaths in the United States. Due to screening examinations used to detect and remove premalignant colon polyps, as well as modification of risk factors and improvements in the treatment of CRC, the incidence and mortality due to CRC have declined over the last several decades. Regardless, CRC continues to account for about 9% of all cancer deaths in the United States. This review addresses CRC, including the epidemiology, pathophysiology and genetics, screening modalities, treatment, and complications associated with CRC screening. Figures show etiologies of CRC, multiple sessile adenomas, a pedunculated adenoma, a sessile polyp, a large polyp found on computed tomographic colonography, and a characteristic sessile serrated adenoma/polyp with a mucus cap in the proximal colon. Tables list oncogenes, tumor suppressor genes, and mismatch repair genes involved in CRC; surveillance recommendations based on a family history of CRC; CRC risk stratification; CRC screening recommendations by risk stratification; and CRC surveillance recommendations.

This review contains 6 highly rendered figures, 5 tables, and 82 references. 

Although sporadic polyps in the gastrointestinal tract are common with increasing age, the finding of a large number of polyps raises suspicion for a hereditary polyposis syndrome associated with a germline genetic mutation. Because many of these hereditary polyposis syndromes also confer an increased risk of gastrointestinal and extraintestincal cancers, implicated in approximately 1% of all colorectal cancers, recognition of these syndromes is critical to offer preventive screening measures. A key distinguishing feature is polyp histologic type, ranging from adenomatous, to serrated, to hamartomatous. A clinical diagnosis can be confirmed by genetic testing for a germline mutation in known cancer susceptibility genes, although in many polyposis families, a genetic etiology has not yet been identified. This review covers familial adenomatous polyposis, MUTYH-associated polyposis, polyposis associated with polymerase proofreading, juvenile polyposis syndrome, PTEN hamartoma tumor syndromes, hereditary mixed polyposis syndrome, and serrated polyposis. The figures shows the spectrum of histologic types and genetic etiologies of hereditary polyposis syndromes. Tables list polyposis syndromes, American College of Gastroenterology surveillance guidelines for hereditary polyposis syndromes, diagnostic criteria for juvenile polyposis syndrome, diagnostic criteria for PTEN hamartoma tumor syndrome, and World Health Organization diagnostic criteria for serrated polyposis syndrome.

This review contains 1 highly rendered figure, 5 tables, and 172 references

Key words: Familial adenomatous polyposis; Polyposis syndromes; Gastrointestinal polyps; Hereditary polyposis syndromes

Enteral nutrition therapy is a dietary treatment regimen for inflammatory bowel disease that has the benefit of avoiding suppression of the immune system. Its mechanism of action has not been well characterized, but may be related to the elimination of dietary antigens or modulation of the gut microbiota. This treatment has shown success for induction of remission, and may also have a role in maintenance of remission. In the pediatric population, enteral nutrition therapy has the dual benefit of targeting both the inflammatory processes and the poor growth of these patients. This review details the administration and mechanism of action of enteral nutritional therapy, the induction and maintenance of remission, the impact of enteral nutritional therapy on growth and nutrition, and side effects and quality of life. A table summarizes studies investigating enteral nutritional therapy for induction of remission.

This review contains 1 table and 49 references.

Appendicitis is defined as inflammation of the vermiform appendix. It is the most common abdominal surgical emergency and occurs at an annual rate of approximately one in 10,000 in the United States. The lifetime risk of appendicitis is about 9% for males and 7% for females; approximately 80% of cases occur before 45 years of age. Appendicitis rarely occurs in infants; it increases in frequency between 2 and 4 years of age and reaches a peak between the ages of 10 and 19 years. However, clinicians must maintain a high index of suspicion in patients of all age groups. This review covers the pathophysiology, stabilization and assessment, and diagnosis and treatment of complicated and uncomplicated appendicitis. The disposition and outcomes are also reviewed. Figures show an image of appendicitis on a bedside sonogram, and a computed tomographic image of appendicitis. Tables list likelihood ratios of signs and symptoms of appendicitis, the sonographic appearance of appendicitis, the Alvarado scoring system, and the differential diagnosis of appendicitis.

 This review contains 2 figures, 7 tables, and 36 references.

Key words: appendicitis, obstructed appendiceal lumen, rebound abdomen, right lower quadrant pain, ruptured appendix

Anorectal disorders can generate considerable patient discomfort and disability. Although mortality due to such complaints is very low, it is important for the clinician to maintain a high index of suspicion for systemic illness caused by an anorectal source. A detailed history and physical examination should be performed, and the need for imaging or procedures should be assessed. This review examines the pathophysiology, stabilization and assessment, diagnosis and treatment, and disposition and outcomes for patients with anorectal disorders. Figures show the important structures of the anal canal; differences in the anatomy of the origin of internal and external hemorrhoid venous supplies; depictions of a typical anodermal linear tear; Foley catheter–assisted rectal foreign body removal technique; and pertinent anatomy related to a prolapsed rectum through the anus; and types and locations of anorectal abscesses and fistulas. Tables list common painful and painless anorectal disorders; key differences in anal canal structures above and below the pectinate line; anal symptoms mistakenly attributed to hemorrhoids; internal hemorrhoidal grading, description, and recommended treatment; Rome III criteria for the diagnosis of constipation; and a summary of anorectal conditions.

This review contains 6 figures, 12 tables, and 86 references.

Keywords: functional constipation; PEG; abdominal radiographs; pediatric constipation

Gastrointestinal infections, which present with acute diarrhea, sometimes accompanied by vomiting, are an extremely common medical complaint, with an annual incidence of 0.6 illnesses per person. Transmission can occur from animals to person, from person to person, or by the ingestion of contaminated foodstuffs. In the United States, more than 90% of cases are caused by viruses, with norovirus being by far the most common. Common among bacterial causes of acute gastrointestinal infection are Salmonella, Campylobacter, Shigella, Shiga toxin–producing Escherichia coli, Vibrio,Yersinia, and Clostridium difficile. These infections are typically self-limited, but depending on the etiologic agent and characteristics of the host, antibiotic therapy may be indicated. Certain gastrointestinal infections are associated with significant complications, including reactive arthritis, Guillain-Barré syndrome, or septicemia.

This review contains 4 figures, 7 tables, and 60 references.

Key words: Campylobacter, Escherichia coli, Guillain-Barré syndrome,reactive arthritis, Shiga toxin, Shigella, Vibrio, Yersinia

Small bowel obstruction can be a surgical emergency, and may be the ultimate diagnosis in 2 to 15% of patients presenting to the emergency department with abdominal pain. Bowel obstruction can be either mechanical (caused by extrinsic compression, twisting of the bowel, or intrinsic obstruction) or functional (caused by an impaired ability of the bowel to propel contents distally). The most common cause of small bowel obstruction in the developed world is postoperative adhesions.This review examines the pathophysiology, stabilization and assessment, diagnosis and treatment, and outcomes for patients with bowel obstruction.

This review contains 4 figures, 9 tables, 5 videos and 21 references.

Keywords: Bowel obstruction; Small bowel obstruction; Bowel peristalsis; Small intestinal peristalsis; Obstipation; Postoperative adhesions; Pendulous peristalsis; Decreased peristalsis

Hernia is defined as an abnormal protrusion of an organ or tissue through a pathologic defect in its surrounding wall. Overall, hernia is common and is generally believed to be a benign condition associated with some morbidity, although it is not thought to be associated with significant mortality. Between 2001 and 2010, 2.3 million inpatient abdominal hernia repairs were performed in the United States, of which 567,000 were performed emergently. In some cases, a hernia can be a deadly condition. In 2002, hernia was listed as the cause of death for 1,595 US citizens. This review covers the pathophysiology, stabilization and assessment, diagnosis and treatment, and disposition and outcomes of hernia. Figures show anatomic locations of the various abdominal wall, groin, lumbar, and pelvic floor hernias; a direct inguinal hernia; an indirect inguinal hernia; point-of-care sonograms showing a ventral wall hernia and an abdominal wall hernia; and the differential diagnosis of an abdominal mass based on anatomic location. Tables list risk factors for the development of inguinal hernia, sex-based differences in inguinal hernia development, risk factors for the development of incisional hernia, factors to consider when assessing the patient for a hernia, and factors associated with the highest rates of incarceration in patients with groin hernia.

Key words: emergent hernia, hernia incarceration, incisional hernia, inguinal hernia, strangulated hernia

This review contains 6 highly rendered figures, 5 tables, and 66 references.

Appendicitis became recognized as a surgical disease during a presentation by pathologist R. H. Fitz at the 1886 meeting of the Association of American Physicians. In 1894, Charles McBurney first described the surgical technique that was to become the gold standard for appendectomy. Although the appendectomy has traditionally been performed as an open procedure, laparoscopy holds several advantages, such as a lower risk of wound infection, the ability to thoroughly explore the abdominal cavity, and improved outcomes in women of childbearing age, obese patients, and patients with unclear diagnoses. This review covers operative technique, special considerations, and complications and outcome evaluation associated with appendectomy. 

This review contains 12 figures, 7 tables and 91 references.

Keywords: Appendicitis, open appendectomy, laparoscopic appendectomy, larparoscopy, appendiceal tumor, abdominal emergency, appendiceal rupture

Patients who are immunosuppressed either due to an underlying disease process or medications to treat a disease require important perioperative considerations. Preoperative evaluation mandates a higher index of suspicion for pathology given that peritoneal and systemic markers of illness may be masked. Intraoperatively, consideration should be given for diversion more frequently than in a nonimmunosuppressed patient. Postoperatively, patients should be managed in a multidisciplinary fashion. This review largely focuses on the immunosuppressive mediations used for the treatment of inflammatory bowel disease, benign colorectal disease in an immunosuppressed patient, and colorectal malignancies in immunosuppressed patients to highlight important considerations for this patient population.

This review contains 4 figures, 5 tables, and 78 references.

Key words: anal squamous cell carcinoma, appendicitis versus typhlitis, biologic therapy, corticosteroids, human papillomavirus, immunosuppression, neutropenic enterocolitis 

Enteral nutrition (EN) is recognized as a medical nutrition therapy for patients with a functional gastrointestinal tract who are unable to maintain their weight and health by oral intake alone either due to a highly catabolic medical condition or a functional limitation. EN support provides calories and protein to help improve or maintain adequate weight, lean body mass, and overall nutritional status. EN also provides nonnutritive benefits such as maintaining intestinal integrity, supporting the immune system, and preventing infection. EN support can be tailored to a patient’s nutrient needs, and there are various formulas that vary in composition of macronutrients, concentration, and electrolytes for specific disease processes or conditions that may help with tolerance and absorption. EN support complications include issues with access, diarrhea, constipation, electrolyte abnormalities, hyperglycemia, and dehydration/overhydration. Generally, EN is well tolerated. While a patient is on this type of nutrition support, it is important to closely monitor tolerance, weight, laboratory values if indicated, and overall clinical progress, with adjustment to the regimen as needed.

This review contains 1 figure, 4 tables, and 48 references.

Key words: enteral access, enteral formula, enteral nutrition support, gastric residuals, gastrointestinal tract, immunonutrition, malnutrition, medical nutrition therapy, tube feed formula, tube feed tolerance, tube feeding, volume-based feeding