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Common small and large intestinal surgical diseases Part I

Common small and large intestinal surgical diseases Part I. Khayal AlKhayal , MD, FRCSC Assistant Professor of Surgery Consultant Colorectal Surgeon 2010. Topics. Bowel obstruction. Small bowel neoplasms. Meckele’s diverticulum. IBD. Colorectal cancer. Intestinal Obstruction.

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Common small and large intestinal surgical diseases Part I

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  1. Common small and large intestinal surgical diseasesPart I KhayalAlKhayal, MD, FRCSC Assistant Professor of Surgery Consultant Colorectal Surgeon 2010 Shwartz

  2. Topics • Bowel obstruction. • Small bowel neoplasms. • Meckele’s diverticulum. • IBD. • Colorectal cancer. Shwartz

  3. Intestinal Obstruction • Intestinal obstruction exists when blockage prevents the normal flow of intestinal contents through the intestinal tract. • Two types of processes can impede this flow. • Mechanical. • Functional.

  4. Intestinal Obstruction • Mechanical obstruction: • An intraluminal obstruction or a mural obstruction from pressure on the intestinal walls occurs. • Examples are: • intussusception • polypoid tumors and neoplasms • Stenosis • Strictures • Adhesions • Hernias • abscesses.

  5. Intestinal Obstruction • Functional obstruction: • The intestinal musculature cannot propel the contents along the bowel. • Examples are: • Amyloidosis • Muscular dystrophy • Endocrine disorders such as diabetes mellitus • Neurologic disorders

  6. Intestinal Obstruction • The obstruction can be partial or complete. • Its severity depends on: • The region of bowel affected • The degree to which the lumen is occluded • The degree to which the vascular supply to the bowel wall is disturbed.

  7. Intestinal Obstruction • Most bowel obstructions occur in the small intestine • Adhesions are the most common cause of small bowel obstruction, followed by hernias and neoplasms. • Other causes include intussusception, volvulus (ie, twisting of the bowel), and paralytic ileus. • About 15% of intestinal obstructions occur in the large bowel; most of these are found in the sigmoid colon

  8. SMALL-BOWEL OBSTRUCTION • Epidemiology • The most frequently encountered surgical disorder. • ≥75% is due to intra-abdominal adhesions. • Other Dx. should be considered: • Hernias • Crohn’s disease • Intestinal malrotation • Mid-gut volvulus Shwartz

  9. SMALL-BOWEL OBSTRUCTION • Causes: Shwartz

  10. SMALL-BOWEL OBSTRUCTION • Causes can be divided into three categories: • Extraluminal causes such as adhesions, hernias, carcinomas, and abscesses • Intrinsic to the bowel wall (e.g., primary tumors) • Intraluminal obturator obstruction (e.g., gallstones, enteroliths, foreign bodies, and bezoars) Shwartz

  11. SMALL-BOWEL OBSTRUCTION • PATHOPHYSIOLOGY: • Obstruction onset • Gas and fluid accumulate within the intestinal lumen proximal to the site of obstruction. • The bowel distends and intramural pressures rise. • Microvascular perfusion to the intestine is impaired, leading to intestinal ischemia, and, ultimately, necrosis. • ( strangulating bowel obstruction) • Progression to strangulation occurs quicker with complete bowel obstruction and more rapidly with closed loop obstruction which a segment of intestine is obstructed both proximally and distally (e.g., with volvulus). Shwartz

  12. BOWEL OBSTRUCTION • Clinical Presentation • Symptoms: • colicky abdominal pain • Nausea • Vomiting • obstipation • Continued passage of flatus and/or stool beyond 6–12 h after onset of symptoms is characteristic of partial rather than complete obstruction. • Signs • abdominal distention • hyperactive bowel sounds. “borborygmi” • Features of strangulated obstruction include • Tachycardia • Localized abdominal tenderness • Fever • Marked leukocytosis • Acidosis Shwartz

  13. SMALL-BOWEL OBSTRUCTION • Diagnosis • The diagnostic evaluation should focus on the following goals: • Distinguishing mechanical obstruction from ileus • Determining the etiology of the obstruction • Discriminating partialfrom complete obstruction • Discriminating simplefrom strangulating obstruction. • Determining the site of obstruction. Shwartz

  14. SMALL-BOWEL OBSTRUCTION • Diagnosis • Careful history taking: • prior Hx of abdominal operations  ? presence of adhesions. • Hx of abdominal disorders (e.g., intraabdominal cancer or inflammatory bowel disease). • Careful examination: • a meticulous search for hernias (particularly in the inguinal and femoral regions) should be conducted. • The stool should be checked for gross or occult blood, the presence of which is suggestive of intestinal strangulation. Shwartz

  15. LARGE BOWEL OBSTRUCTION :Pathophysiology • As in small bowel obstruction • large bowel obstruction results in an accumulation of intestinal contents, fluid, and gas proximal to the obstruction. • Obstruction in the large bowel can lead to severe distention and perforation unless some gas and fluid can flow back through the ileal valve. • Large bowel obstruction, even if complete, may be undramatic if the blood supply to the colon is not disturbed.

  16. LARGE BOWEL OBSTRUCTION :Pathophysiology • If the blood supply is cut off  intestinal strangulation and necrosis (ie, tissue death) occur; this condition is life threatening. • dehydration occurs more slowly than in the small intestine because the colon can absorb its fluid contents and can distend to a size considerably beyond its normal full capacity.

  17. LARGE BOWEL OBSTRUCTION :Clinical Manifestations • Large bowel obstruction differs clinically from small bowel obstruction in that the symptoms develop and progress relatively slowly. • In patients with obstruction in the sigmoid colon or the rectum, constipation may be the only symptom for days. loops of large bowel become visibly outlined through the abdominal wall, and the patient has crampy lower abdominal pain. • Finally, fecal vomiting develops. Symptoms of shock may occur.

  18. SMALL-BOWEL OBSTRUCTION • X-RAY SERIES: • Obstruction is usually confirmed with radiographic examination. • Abdominal series consists of : • supine Abdominal X-ray • upright Abdominal X-ray • Upright Chest X-ray • The finding most specific for small-bowel obstruction is the triad of • dilated small-bowel loops (>3 cm in diameter) • air–fluid levels seen on upright films • a paucity of air in the colon. • False negative : • Proximal obstruction • The bowel lumen is filled with fluid but no gas. Shwartz

  19. Assessment and Diagnostic Findings • Diagnosis is based on symptoms and on x-ray studies. • Abdominal x-ray studies (flat and upright) show a distended colon. • Barium studies are contraindicated.

  20. Plain x-rays Shwartz

  21. SMALL-BOWEL OBSTRUCTION • CT Abdomen: • Findings include: • A discrete transition zone with dilation of bowel proximally, decompression of bowel distally • intraluminal contrast that does not pass beyond the transition zone • Colon containing little gas or fluid. • Strangulation is suggested by: • Thickening of the bowel wall • Pneumatosis intestinalis (air in the bowel wall) • Portal venous gas • Mesenteric haziness • Poor uptake of intravenous contrast into the wall of the affected bowel. • CT scanning also offers a global evaluation of the abdomen and may therefore reveal the etiology of obstruction. Shwartz

  22. SMALL-BOWEL OBSTRUCTION Shwartz

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  26. SMALL-BOWEL OBSTRUCTION • SMALL-BOWEL SERIES (SMALL-BOWEL FOLLOW-THROUGH) • can be helpful • contrast is swallowed or instilled into the stomach through a nasogastric tube. • Barium or water-soluble contrast agents (Gastrografin) • ENTEROCLYSIS • 200– 250mLof barium followed by 1–2 L of a solution of methylcellulose in water is instilled into the proximal jejunum via a long nasoenteric catheter. • Enteroclysis is rarely performed in the acute setting • Offers greater sensitivity for lesions that may be causing partial small-bowel obstruction. Shwartz

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  30. BOWEL OBSTRUCTION • Therapy • Fluid resuscitation. • A nasogastric (NG) tube to evacuate air and fluid from stomach. • An indwelling bladder catheter to monitor urine output. • Central venous or pulmonary artery catheter monitoring may be necessary • Broad-spectrum antibiotics • The standard therapy for bowel obstruction is expeditious surgery with the exception of specific situations Shwartz

  31. ILEUS • Caused by impaired intestinal motility • It is characterized by S/S of intestinal obstruction in the absence of a lesion-causing mechanical obstruction. • Ileus is temporary and generally reversible if the inciting factor can be corrected. Shwartz

  32. ILEUS • Pathophysiology • The most frequently encountered factors are • abdominal operations • How? : surgical stress-induced sympathetic reflexes, inflammatory response-mediator release, and anesthetic/analgesic effects, each of which can inhibit intestinal motility. • infection and inflammation • viral infections, such as those associated with CMV & EBV • electrolyte abnormalities • drugs. Shwartz

  33. ILEUS • Diagnosis • Routine postoperative ileus should be EXPECTED and requires no diagnostic evaluation • If ileus persists beyond 3–5 days postoperatively or occurs in the absence of abdominal surgery  diagnostic evaluation is needed • rule out the presence of mechanical obstruction is warranted. • Patient medication lists should be reviewed for the presence of drugs known to be associated with impaired intestinal motility. • Measurement of serum electrolytes may demonstrate hypokalemia, hypocalcemia, hypomagnesemia, hypermagnesemia, or other electrolyte abnormalities • Abdominal radiographs • In the postoperative setting, CT scanning is the test of choice because it can demonstrate the presence of an intraabdominal abscess or other evidence of peritoneal sepsis that may be causing ileus and can exclude the presence of complete mechanical obstruction. Shwartz

  34. ILEUS • Therapy • limiting oral intake and correcting the underlying inciting factor. • Nasogastric decompression, If vomiting or abdominal distention are prominent, • Fluid and electrolytes should be administered intravenously until ileus resolves. • If the duration of ileus is prolonged, TPN may be required. • Surgery should be avoided if at all possible. • Prokinetic agents, such as metoclopramide and erythromycin, are associated with poor efficacy. Shwartz

  35. SMALL-BOWEL NEOPLASMS • Epidemiology • Benign: • Adenomasare the most common benign neoplasm of the small intestine. • Other benign tumors include fibromas, lipomas, hemangiomas, lymphangiomas, and neurofibromas. • Cancer • Primary small-bowel cancers are rare • estimated incidence of 5300 cases per year in the United States. • Adenocarcinomas: comprise 35–50 percent of all cases • carcinoid tumors comprise 20–40 percent • lymphomas comprise approximately 10–15 percent. • Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors arising in the small intestine and comprise up to 15 percent of smallbowel malignancies.

  36. SMALL-BOWEL NEOPLASMS • Epidemiology • The small intestine is frequently affected by metastases from or local invasion by cancers originating at other sites. • Melanoma, in particular, is associated with a propensity for metastasis to the small intestine. • Risk factors for developing small-intestinal adenocarcinoma include: • Consumption of red meat • Ingestion of smoked or cured foods • Crohn disease • Celiac sprue • Hereditary nonpolyposis colorectal cancer (HNPCC) • Peutz-Jeghers syndrome. • Familial adenomatous polyposis (FAP) • nearly 100 % cumulative lifetime risk of developing duodenal adenomas that have the potential to undergo malignant transformation. • The risk of duodenal cancer in these patients is more than 100-fold than in the general population. Shwartz

  37. SMALL-BOWEL NEOPLASMS • Clinical Presentation • Most small-intestinal neoplasms are asymptomatic until they become large. • S/S of Partial small-bowel obstruction, is the most common mode of presentation. • Hemorrhage, usually indolent, is the second most common mode of presentation. • Physical examination may reveal an abdominal mass or signs of intestinal obstruction. • Fecal occult blood test may be positive. Cachexia or ascites may be present with advanced disease. • Lesions in the periampullary location can cause obstructive jaundice or pancreatitis. • Adenocarcinomas located in the duodenum tend to be diagnosed earlier in their progression than those located in the jejunum or ileum, which are rarely diagnosed prior to the onset of locally advanced or metastatic disease. Shwartz

  38. SMALL-BOWEL NEOPLASMS Carcinoid tumors of the small intestine are also usually diagnosed after the development of metastatic disease. • These tumors are associated with a more aggressive behavior than the more common appendiceal carcinoid tumors. • Approximately 25–50% with carcinoid tumor-derived liver metastases will develop manifestations of the carcinoid syndrome. • include diarrhea, flushing, hypotension, tachycardia, and fibrosis of the endocardium and valves of the right heart. Shwartz

  39. Lymphoma • may involve the small intestine primarily or as a manifestation of disseminated systemic disease. • Primary small-intestinal lymphomas are most commonly located in the ileum, which contains the highest concentration of lymphoid tissue in the intestine. • partial small-bowel obstruction is the most common mode of presentation • 10 percent of patients with small intestinal lymphoma present with bowel perforation. Shwartz

  40. GISTs • 60-70%are located in the stomach. • The small intestine is the second most common site, containing 25–35%. • GISTs have a greater propensity to be associated with overt hemorrhage than the other small-intestinal malignancies. • Metastatic tumors • involving the small intestine can induce intestinal obstruction and bleeding. Shwartz

  41. SMALL-BOWEL NEOPLASMS • Diagnosis • rarely diagnosed preoperatively. • Laboratory tests are nonspecific, with the exception of elevated serum 5-hydroxyindole acetic acid (5-HIAA) levels in patients with the carcinoid syndrome. • Contrast radiography of the small intestine may demonstrate benign and malignant lesions. • Enteroclysis has a sensitivity of greater than 90% • Tumors associated with significant bleeding can be localized with angiography or radioisotope-tagged red blood cell (RBC) scans. • Tumors located in the duodenum can be visualized and biopsied on EGD. Shwartz

  42. SMALL-BOWEL NEOPLASMS • Therapy • Benign neoplasms of the small intestine that are symptomatic should be surgically resected or removed endoscopically, if feasible. • The surgical therapy of small-intestinal malignancies usually consists of wide–local resection of the intestine harboring the lesion. • For most adenocarcinomas of the duodenum, except those in the distal duodenum, pancreaticoduodenectomy is required. • In the presence of locally advanced or metastatic disease, palliative intestinal resection or bypass is performed. Shwartz

  43. SMALL-BOWEL NEOPLASMS • Chemotherapy has no proven efficacy in the adjuvant or palliative treatment of small-intestinal adenocarcinomas. • Octreotide is the most effective pharmacologic agent for management of symptoms of carcinoid syndrome. • GISTs are resistant to conventional chemotherapy agents. • Imatinib (Gleevec, formerly known as ST1571) is a tyrosine kinase inhibitor with potent activity against tyrosine kinase KIT. • Lymphoma • Localized small-intestinal lymphoma should be treated with segmental resection • Diffused small intestine lymphoma should be treated by chemotherapy Shwartz

  44. What’s this? Shwartz

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  46. MECKEL DIVERTICULUM • Epidemiology • It is a true diverticulum because its wall contains all of the layers found in normal small intestine. • Reminant of omphalomesenteric duct. • Most common cong. Abnormality in GIT. • ~ 60% contain heterotopic mucosa, of which more than 60% consist of gastric mucosa. • “rule of twos”: • 2 % prevalence • 2:1 female predominance • Location 2 feet proximal to the ileocecal valve in adults • Half of those who are symptomatic are younger than 2 years of age. Shwartz

  47. MECKEL DIVERTICULUM • Clinical Presentation • Usually asymptomatic unless associated complications arise. • Bleeding is the most common presentation in children • Intestinal obstruction is the most common presentation in adults with Meckeldiverticula • Diverticulitis, present in 20 %, and is associated with a clinical syndrome that is indistinguishable from acute appendicitis. Shwartz

  48. MECKEL DIVERTICULUM • Diagnosis • In the absence of bleeding, Meckeldiverticula rarely are diagnosed prior to the time of surgical intervention for another cause. • Enteroclysis is associated with an accuracy of 75 percent, but is usually not applicable during acute presentations of complications related to Meckeldiverticula. • Radionuclide scans (99mTc-pertechnetate) suggest the diagnosis of Meckeldiverticulum when uptake occurs in associated ectopic gastric mucosa, or when extravasation occurs during active bleeding. • Angiography can localize the site of bleeding during acute hemorrhage related to Meckeldiverticula. Shwartz

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