SURGICAL CONDITIONS OF THE INTESTINES

ANATOMY AND PHYSIOLOGY OF THE SMALL INTESTINE Small bowel consists of: Duodenum, jejunum, ileum Main role of duodenum: chemical digestion of chyme Types of activity patterns: peristalsis and segmentations

ANATOMY AND PHYSIOLOGY OF THE SMALL INTESTINE Main role of jejunum: Absorb nutrients from chyme In ileum: chyme accumulates and awaits the opening of the ileocecal sphincter to enter the large bowel

DIVERTICULOSIS OF THE SMALL INTESTINE Multiple saclike mucosal herniations through weak points in the intestinal wall. Less common than colonic diverticula.  Cause: Not known. Believed to develop as the result of abnormalities in peristalsis, intestinal dyskinesis (inability to control movement) and high segmental intraluminal pressures. Classified as true and false. True diverticula -> composed of all layers of the intestinal wall False diverticula -> herniation of the mucosal and submucosal layers

DIVERTICULOSIS OF THE SMALL INTESTINE Small bowel diverticula are generally asymptomatic  Patients who develop symptoms generally report symptoms that reflect associated complications. The most common symptom is nonspecific epigastric pain or a bloating sensation.  Complications: -Chronic abdominal pain -Diverticulitis -Intestinal obstruction -Intestinal hemorrhage -Malabsorption The prognosis is good even with complications. asymptomatic diverticula, conservative approach & avoid constipation painful diverticular disease involves adding fiber to the diet and not eating foods that cause gas, pain, or other symptoms. 

MECKEL’S DIVERTICULUM -Most common congenital abnormality of the gastrointestinal tract. -Embryologic problem of the vitellin duct -Found in 1% to 2% of the population, with slightly higher male incidence -Typical location; distal ileum Complications are rare but if they happen: -children; occult bleeding from diverticulum, manifesting as unexplained anemia. Brisk hemorrhage, melena or even hematochezia has been seen. -adult; bowel obstruciton Rarely diagnosed preoperatively [acute appendicitis]

MECKEL’S DIVERTICULUM Surgical treatment: In the acute setting, limited resection of the ileal segment containing the diverticulum with primary anastomosis is indicated.

TUMORS OF THE SMALL INTESTINE Malignant neoplasms of the small bowel are among the rarest types of cancer (2% of all GI cancers) Most are never discovered. When discovered often metastasized to distant sites. Reason: difficult to see small bowel with endoscopy. Most are benign and asymptomatic. Symptoms: GI bleeding , small bowel obstruction, instussuseption (part of intestine slides into adjacent part of intestine). If tumor is malignant other typical cancer symptoms can exist (fatigue, anemia, weight loss)

TUMORS OF THE SMALL INTESTINE Benig neoplasms Most small bowel neoplasms are benign and found coincidentally Small bowel polyps should be removed and biopsed Malignant neoplasms Include: ->gastrointestinal stromal tumors Mostly found in ileum Bleeding Treatment: resection ->Adenocarcinoma 40% Mostly found in duodenum or proximal jejunum Treatment : whipples procedure (pancreaticoduodenectomy) or palliative stenting ->Carcinoid tumor 30% Serotonin secreting tumor Carcinoid syndrome->flushing, wheezing, diarrhea Mostly found in appendix. Also ileum. For acute symtoms octreotide or cyproheptadine

TUMORS OF THE SMALL INTESTINE ->small bowel lymphoma 20% increaed incidense in patients who are immunocompromised, have crohns or celiac disease. Treatment: resection. If disease is disseminated->chemotherapy

SHORT BOWEL SYNDROME A complication related to extensive small bowel resection/damage. Inadequate small bowel to absorb nutrients, fats, vitamins, electrolytes. Symptoms: Malnutrition, weigh loss, abdominal pain, symproms related to vitamin and mineral deficiencies (esp. B12 deficiency if you remove parts of terminal ileum) Diagnosis; history of small bowel resection/damage Treatment; adequate oral nutrition. Increased caloric intake, vitamine and mineral supplementation, anti-peristaltic agents to slow things down. Important parameters, always check in resection of small bowel; electrolyte , urine output, serum albumin, weight

ANATOMY AND PHYSIOLOGY OF THE LARGE INTESTINE Large intestinal task: absorb water and vitamins while converting digested food into feces

NONSPECIFIC INFLAMMATIONS OF THE LARGE INTESTINE Inflammatory Bowel Disease • Ulcerative colitis - nonspecific inflammatory bowel disease of unknown etiology that effects the mucosa of the colon and rectum • Crohn’s disease - nonspecific inflammatory bowel disease that may affect any segment of the gastrointestinal tract • Indeterminate colitis – 15% patients with IBD impossible to differentiate

NONSPECIFIC INFLAMMATIONS OF THE LARGE INTESTINE Idiopathic inflammatory autoimmune disease process involving GI tract Can happen to anybody but 20s and 30s more common. Increased risk of colon cancer Two types: Chrons diseasse Ulcerative colitis Symptoms: chronic abdominal pain, bloody diarrhea (the inflammation of bowel makes it difficult to absorb water), mucus in stool, systemic symptoms (fever, weight loss, sweats, malaise, arthralgia, nausea, vomiting) Extraintestinal symtoms: skin, eyes, joints, liver Colonoscopy with biopsy gold standard for diagnosis.

NONSPECIFIC INFLAMMATIONS OF THE LARGE INTESTINE

NONSPECIFIC INFLAMMATIONS OF THE LARGE INTESTINE Chrons disease: Affect the entire thickness of the tissue and the entire GI tract can be affected. Fistula, aphthous ulcers, chrons ileitis (ulcertion of terminal ileum) ASCA (+) Ulcerative colitis: limited to the large bowel, primarily affects rectum. Tenesmus (earge to defecate but there is no stool) + mucus passage ANCA (+) Treatment: 1st line ASAs Mesalamine derivatives (longterm ) Steroid sparing agents: inhibit inflammation Surgical treatment is curative for UC