Disorders of the Lower GI Tract

Study Notes

Chronic inflammation of intestinal tract is the definition of Inflammatory Bowel Disease (IBD)
IBD is caused by autoimmune, environmental factors, genetic predisposition.
Ulcerative colitis is characterized by ulceration of the colon and rectum.
Ulceration in Ulcerative colitis is distal and continuous
Crohn’s disease can affect any part of the gastrointestinal (GI) tract.
Crohn’s disease causes skip lesions - separated segments.
Diverticular disease is a condition where saclike outpouchings of the mucosal layer of the colon protrude through the muscle layer.
Diverticulosis is asymptomatic diverticular disease while diverticulitis is the inflammation of the diverticula.
Appendicitis is inflammation of the appendix.
Appendicitis is commonly caused by obstruction of the appendix lumen with a fecalith.
Cholelithiasis is the presence of gallstones in the gallbladder.
Risk factors for cholelithiasis include obesity, sedentary lifestyle, and family history.

Ulcerative colitis progresses through inflammation, edema, abscess formation, and ulceration, leading to destruction of epithelium and reduced surface area.
Clinical manifestations of ulcerative colitis include diarrhea, abdominal pain, fever, weight loss, increased heart rate, dehydration, and anemia.
Ulcerative colitis can lead to complications such as hemorrhage, toxic megacolon, and colon cancer.

Crohn's disease is characterized by edematous and swollen areas with ulceration affecting all layers of the affected area.
In Crohn’s disease, the deep ulceration gives the area a cobblestone appearance.
Crohn’s disease clinical manifestations include diarrhea, fatigue, abdominal pain, and weight loss.
Complications of Crohn’s disease include strictures, obstructions, and fistulas.

A low fiber diet, decreased physical activity, and the effects of aging can contribute to diverticular disease.
Diverticuli form at weak points in the wall of the colon.
Reduced diameter and increased pressure within the colon contribute to more diverticuli.
Diverticulitis can occur when the diverticula rupture or when trapped stool causes inflammation.
Clinical manifestations of diverticulitis include fever, chills, increased white blood cell count, and lower left quadrant pain.

Obstruction of the appendix lumen leads to the accumulation of mucosal secretions, resulting in increased pressure and decreased blood flow.
This process can lead to ulceration of the mucosa, further increasing inflammation. Ultimately, the appendix may become gangrenous and perforate.
Clinical manifestations of appendicitis include abdominal pain, rebound tenderness, fever, nausea, and vomiting.
Appendicitis can lead to complications like perforation, peritonitis, and sepsis.