Changes Induced by Drugs and Toxins The etiology of drug-induced colitis varies significantly, as does the underlying pathophysiologic disturbance that results from the drug ingestion. Since drug-induced colitis is likely…
Polyposis and Hereditary Cancer Syndromes Polyposis Syndromes Introduction Polyps develop throughout the gastrointestinal (GI) system either as sporadic lesions or as part of a polyposis or hereditary cancer syndrome. The…
Interpretation of Colonic Biopsies The ability to endoscopically visualize the entire mucosal surface of the large bowel and to biopsy or cytologically sample normal- and abnormal-appearing areas allows clinicians to…
Colitis Due to Venoms Most scorpion and snake venoms contain a mixture of toxic proteins and enzymes that induce circulatory collapse, hemolysis, coagulation abnormalities, and changes in vascular resistance. All…
Changes Induced by Radiographic Substances Barium causes three types of gastrointestinal problems: (a) barium granulomas, (b) bolus obstruction, and (c) an allergic or anaphylactic reaction from the carboxymethylcellulose component of…
Online Chapter 2 CASE 2.1 CLINICAL HISTORY 34-year-old man with fever and abdominal pain. FIGURE 2.1A FIGURE 2.1B FINDINGS Color Doppler ultrasound (US) (A) demonstrates a 3-cm hypoechoic mass in…
Histologic Features The mucosa is smooth and without folds except distally in the rectum. There are no villi. The mucosal surface is flat and regular with interconnected territories containing 10…
Congenital Abnormalities Cecal Agenesis Intestinal agenesis is the failure of a portion of the enteric tube to form. This disorder is rare, occurring in 1 in 50,000 pregnancies. Males are…
Lymphatic Drainage The lymphatics begin as a capillary plexus that wraps around the muscularis mucosae (Fig. 13.10). This plexus sends small branches into the mucosa to reach no higher than…
