Disorders Of The Small And Large Intestine PDF

DISORDERS OF THE SMALL AND LARGE BOWEL  INTRODUCTION Small intestine – 6M First 25 cm (retroperitoneum) – Duodenum First 1/3rd of intraperitoneal part – Jejunum Remainder – Ileum Arterial supply – Superior mesenteric artery  Disorders of the Small Bowel...

DISORDERS OF THE SMALL AND LARGE BOWEL  INTRODUCTION Small intestine – 6M First 25 cm (retroperitoneum) – Duodenum First 1/3rd of intraperitoneal part – Jejunum Remainder – Ileum Arterial supply – Superior mesenteric artery  Disorders of the Small Bowel Non-neoplastic disorders - Congenital anomalies - Malabsorptive disorders - Infectious diseases - Crohn disease and acquired diverticula Neoplasms - Polyps - WHO classification of tumors  CONGENITAL ANOMALIES 1. Heterotopic gastric mucosa 2. Heterotopic pancreas 3. Meckel’s diverticulum 4. Malrotation, stenosis, atresia, duplication and defects of musculature Heterotopic gastric mucosa  Meckel’s Diverticulum A true diverticulum Occurs in the ileum Occurs as a result of failed involution of the vitelline duct Seen in the anti-mesenteric side of the bowel  Meckel’s Diverticulum Rule of 2’s – 2% of population, 2 inches long, within 2 feet of the ileocecal valve, Twice common in males, symptomatic by age 2. Complications – peptic ulceration, bleeding, abdominal pain, intestinal obstruction Meckel’s Diverticulum  Atresia and stenosis Most common site – duodenum Embryologic defect, in utero mechanical injury to vascular system of bowel Complications – perforation, intussuception, brown bowel syndrome (vit E deficiency)  Disorders of the Small Bowel Non-neoplastic disorders - Congenital anomalies - Malabsorptive disorders - Infectious diseases - Crohn disease and acquired diverticula Neoplasms - Polyps - WHO classification of tumors  MALABSORPTIVE DISORDERS CELIAC DISEASE Characterized by malabsorption, abnormal small bowel structure and intolerance to gluten Pathogenesis – sensitivity to gluten (alcohol soluble, water insoluble), protein component of wheat and related (oat, barley and rye) a. Cell mediated immunity b. Virus- adenovirus type 12 c. Toxic – subgroup of gliadin  CELIAC DISEASE - Association with increased milk intolerance in celiac sprue, DM, UC, PBC, Sclerosing cholangitis - Morphology – diffuse enteritis (most severe in small bowel) Atrophy/ loss of villi, increased intraepithelial lymphocytes  TROPICAL SPRUE - Celiac like disease – people living/visiting tropics - Causative agent – no specific ( but implication of E. coli and Hemophilus) - Pathology – variable normal to diffuse enteritis - C/F – malabsorption (no risk of intestinal lymphoma) - Treatment – antibiotics  WHIPPLE DISEASE Rare systemic disease – Hallmark – small intestinal mucosa laden with distended macrophages in the lamina propria Organs involved – any but M.C small instestine(jejunum) At site of infection – inflammation is essentially absent C/F – males, 30-40 years, atypical presentation, >50% lymphadenopathy and skin hyperpigmentation. WHIPPLE DISEASE  Disorders of the Small Bowel Non-neoplastic disorders - Congenital anomalies - Malabsorptive disorders - Infectious diseases - Crohn disease and acquired diverticula Neoplasms - Polyps - WHO classification of tumors  INFECTIOUS DISEASES Infectious enterocolitis common gastrointestinal viruses – Rota virus, Norwalk virus and enteric virus Bacterial enterocolitis – E. coli, Salmonella, Campylobacter, Vibrio cholera, Clostridium perfringens. Epithelial cell invasion – Enteroinvasive E. coli and Shigella Post infectious complications of Campylobacter infection - Reactive arthritis, GB syndrome, Immunoproliferative small intestinal disease  INFECTIOUS DISEASES Parasitic disease Giardiasis - does not induce significant villous architectural change. Diagnosis based on identification of pear shaped trophozoites which can be highlighted by trichrome and Giemsa stains. Ascaris lumbricoides Strongyloides  INFECTIOUS DISEASES Typhoid fever - Salmonella typhi and paratyphi - c/f – acute infection assosciated with bloody diarrhea and flu like symptoms - Morphology – enlargement of Peyer’s patches in the terminal ileum, Oval ulcers oriented along the long axis of the ileum. - Complications – bacteremia and extra intestinal complications. Typhoid fever  Disorders of the Small Bowel Non-neoplastic disorders - Congenital anomalies - Malabsorptive disorders - Infectious diseases - Crohn disease and acquired diverticula Neoplasms - Polyps - WHO classification of tumors  ACQUIRED DIVERTICULA False diverticula Increases with age Most common- duodenum Pathophysiology – bacterial overgrowth, periampullary diverticula causes obstructive jaundice, intestinal obstruction  Disorders of the Small Bowel Non-neoplastic disorders - Congenital anomalies - Malabsorptive disorders - Infectious diseases - Crohn disease and acquired diverticula Neoplasms - Polyps - WHO classification of tumors  POLYPS AND NEOPLASMS BENIGN TUMORS: Adenomas (most common benign neoplasm) - True adenomas : ileum, asymptomatic, associated with bleeding and obstruction - Villous adenomas : duodenum - Brunner’s gland adenoma – duodenum, no malignant potential Leiomyoma - Most common symptomatic benign lesion, - Associated with bleeding  POLYPS AND NEOPLASMS Lipoma – most common in ileum, causes obstruction. Peutz Jeghers polyps - AD, multiple polyps in GIT ( jejunum and ileum are most frequent) - Mucocutaneous melanotic pigmentation - No malignant potential  POLYPS AND NEOPLASMS Adenocarcinoma - Is rare accounting for only 2% of all primary GIT tumors. - Predominant site – duodenum ADENOCARCINOMA  CARCINOID TUMOR - >50 % of malignant tumor in small intestine - Arise from Enterochromaffin cells or Kultchitsky cells - All carcinoids and potentially malignant – tendency for aggression correlative with site - Appendicular and rectal – metastasize infrequently, asymptomatic - Ileal, gastric and colonic – metastasize widely (to lymph nodes and liver) - MC site of GIT carcinoid tumor – Appendix, 2nd MC – Ileum, rectum - Multicentric origin – stomach and ileum CARCINOID TUMOR CARCINOID TUMOR  CARCINOID TUMOR - angulation/obstruction of small intestine. - Vasomotor disturbances – diarhoea, cramps, nausea, vomiting - Intestinal hypermotility - Asthmatic, bronchoconstrictive attack - Hepatomegaly - Systemic fibrosis – cardiac involvement, pulmonary and tricuspid valve thickening and stenosis CARCINOID SYNDROME  Ulcerative colitis Definition Gross features Microscopic features Complications Ulcerative colitis Colon – Ulcerative colitis Ulcerative colitis CROHN DISEASE  CROHN DISEASE Terminal ileum – most common site of involvement - Asymmetric involvement and skip lesions - Predominates on the mesenteric border; the earliest sign in the terminal ileum – apthoid ulcer - Fissure ulcer – distributed in longitudinal and transverse fashion, progress to abscess, sinuses and fistulae - Cobble stone and creeping fat CROHNS  CROHN DISEASE Complications: Malabsorption (iron deficiency anemia, hypoalbuminemia, B12 deficiency), fibrosing strictures, fistulas, intestinal obstruction, perforation and peritoneal abscess. Extra Intestinal manifestation: Uveitis, migratory polyarthritis, sacroilitis, ankylosing spondylitis, erythema nodosum, pericholangitis, primary sclerosing cholangitis. Adenoma-carcinoma Sequence Colo-rectal carcinoma  Intestinal Obstructions Hernia Adhesions Intussusception Volvulus Hernia  Intussusception Definition – When a portion of bowel (intussuscipiens) swallows another length of bowel (intussusceptum). Usually occurs during first 5 years of life – lymphoid hyperplasia In older patients- intra-luminal tumor Complications- Ischemic necrosis Intussusception DIVERTICULOSIS SPOTTERS