外科学教学课件：Small intestine disease

1、Small intestine disease Chapter 1 Anatomy and Physiology The primary role of the small intestine is the digestion and absorption of dietary components after they leave the stomach. Exocrine secretions from the liver and pancreas enable complete digestion of the foodstuffs. The enlarged surface area

2、of the small intestinal mucosa then absorbs these nutrients.Chapter 1 Anatomy and Physiology In addition to its role in digestion and absorption, the small bowel is the largest endocrine organ in the body and is one of the most important organs of immune function. Given its essential role and comple

3、xity, it is amazing that diseases of the small bowel are not more frequent. Chapter 1 Anatomy and Physiology In this chapter, the normal anatomy and physiology of the small intestine are described, as well as disease processes involving the small bowel, which include: obstruction inflammatory diseas

4、es neoplasmsThe entire small intestine, which extends from the pylorus to the cecum, measures 300 to 550 cm：duodenal length at about 20 to 35 cmjejunal length at 100 to 110 cmileal length at 150 to 160 cm. Chapter 1 Anatomy and Physiology 1.Anatomy 2.PhysiologyChapter 1 Anatomy and Physiology There

5、is no obvious line of demarcation between the jejunum and the ileum; however, the jejunum is commonly considered to make up the proximal two fifths of the small intestine, and the ileum makes up the remaining three fifths. 1.AnatomyChapter 1 Anatomy and Physiology1.Anatomy1.1 Neurovascular-Lymphatic

6、 Supply The small intestine is served by rich vascular, neural, and lymphatic supplies, all traversing through the mesentery.肠系膜 The base of the mesentery attaches to the posterior abdominal wall to the left of the second lumbar vertebra and passes obliquely to the right and inferiorly to the right

7、sacroiliac joint.右侧骶髂关节 Chapter 1 Anatomy and Physiology1.Anatomy1.1 Neurovascular-Lymphatic Supply The blood supply of the small bowel, except for the proximal duodenum that is supplied by branches of the celiac axis, comes entirely from the superior mesenteric artery.Chapter 1 Anatomy and Physiolo

8、gy1.Anatomy1.1 Neurovascular-Lymphatic Supply The blood supply of the small bowel, except for the proximal duodenum that is supplied by branches of the celiac axis, comes entirely from the superior mesenteric artery.Chapter 1 Anatomy and Physiology1.Anatomy1.1 Neurovascular-Lymphatic Supply The supe

9、rior mesenteric artery courses anterior to the uncinate process of the pancreas and the third portion of the duodenum, where it divides to supply the pancreas, distal duodenum, entire small intestine, and ascending and transverse colon. Venous drainage of the small bowel parallels the arterial suppl

10、y, with blood draining into the superior mesenteric vein, which joins the splenic vein,then to the the portal vein .The innervation of the small bowel is provided by both parasympathetic and sympathetic divisions of the autonomic nervous system, which in turn provide the efferent nerves to the small

11、 intestine. Chapter 1 Anatomy and Physiology1.Anatomy1.2 Microscopic AnatomyThe small bowel wall consists of four layers: Serosa浆膜muscularis propria肌层Submucosa粘膜下mucosa 黏膜Chapter 1 Anatomy and Physiology1.AnatomyChapter 1 Anatomy and Physiology 1.Anatomy 2.PhysiologyDigestion and Absorption Function

12、 The complex process of digestion and eventual absorption of nutrients, water, electrolytes, and minerals is the main role of the small intestine. The small bowel is primarily responsible for absorption of the dietary components (carbohydrates, proteins, and fats), as well as ions, vitamins, and wat

13、er.Endocrine Function In fact, the small bowel is the largest endocrine organ in the body. Immune Function The small intestine serves as a major immunologic barrier in addition to its important role in digestion and endocrine function. As a result of constant antigenic exposure, the intestine posses

14、ses abundant lymphoid cells (i.e., B and T lymphocytes) and myeloid cells (macrophages, neutrophils, eosinophils, and mast cells). To deal with the constant barrage of potential toxins and antigens, the gut has evolved into a highly organized and efficient mechanism for antigen processing, humoral i

15、mmunity, and cellular immunity.Chapter 2 Inflammatory diseases 1.Crohns Disease 克罗恩病2.Tuberculosis of intestine肠结核3.Typhoid enteritis 伤寒4.Acute hemorrhagic enteritis急性出血性肠炎1.Crohns Disease Crohns disease is a chronic, transmural inflammatory disease慢性透壁性炎症 of the gastrointestinal tract of unknown ca

16、use. Although Crohns disease most commonly affects the end of the small intestine (the ileum) and the beginning of the large intestine (the colon), it may involve any part of the GI tract. 可涉及消化道全长小肠末，大肠始常发炎性溃疡Chapter 2 Inflammatory diseases 1.Crohns Disease The disease is named after Dr. Burrill B.

17、 Crohn in 1932.Crohns and a related disease, ulcerative colitis溃疡性结肠炎, are the two main disease categories that belong to a larger group of illnesses called inflammatory bowel disease (IBD). 炎性肠病 Because the symptoms of these two illnesses are so similar, it is sometimes difficult to establish the d

18、iagnosis definitively. Chapter 2 Inflammatory diseases 1.Crohns Disease Chapter 2 Inflammatory diseases 1.1 Incidence and Epidemiology Crohns disease is the most common primary surgical disease of the small bowel, with an annual incidence of 3 to 7 cases per 100,000 of the general population; the in

19、cidence is highest in North America and Northern Europe. Crohns disease primarily attacks young adults in the second and third decades of life. The risk for developing Crohns disease is about two times higher in smokers than in nonsmokers. Although Crohns disease is uncommon in African blacks, black

20、s in the United States have rates similar to whites. Certain ethnic groups, particularly Jews, have a greater incidence of Crohns disease than do age- and gender-matched control subjects. 1.Crohns Disease Chapter 2 Inflammatory diseases 1.2 Etiology病因不清 The cause of Crohns disease remains unknown. A

21、 number of potential causes have been proposed, with the most likely possibilities being infectious, immunologic, and genetic. Other possibilities that have met with various levels of enthusiasm include environmental and dietary factors, smoking, and psychosocial factors. 1.Crohns Disease Chapter 2

22、Inflammatory diseases 1.3 Pathology The most common sites of occurrence of Crohns disease are the small intestine and colon. The involvement of both large and small intestine has been noted in about 55% of patients. 30% of patients present with small bowel disease alone.in 15%, the disease appears l

23、imited to the large intestine.Crohns disease can also involve the mouth, esophagus, stomach, duodenum, and appendix.肛裂，肛周脓肿也常见1.Crohns Disease Chapter 2 Inflammatory diseases 1.3 Pathology Section of colectomy showing transmural inflammation1.Crohns Disease Chapter 2 Inflammatory diseases 1.4 Clinic

24、al Manifestations Crohns disease can occur at any age, but the typical patient is a young adult in the second or third decade of life. Characteristically, there are symptomatic periods of abdominal pain and diarrhea interspersed with asymptomatic periods of varying lengths. With time, the symptomati

25、c periods gradually become more frequent, more severe, and longer lasting. 1.Crohns Disease Chapter 2 Inflammatory diseases 1.4 Clinical ManifestationsAbdominal pain:可为脐周The most common symptom is intermittent and colicky abdominal pain, most commonly noted in the lower abdomen. The pain, however, m

26、ay be more severe and localized and may mimic the signs and symptoms of acute appendicitis. Diarrhea:不典型Diarrhea is the next most frequent symptom and is present, at least intermittently, in about 85% of patients. In contrast to ulcerative colitis, patients with Crohns disease typically have fewer b

27、owel movements, and the stools rarely contain mucus, pus, or blood. Systemic nonspecific symptoms :a low-grade fever (present in about 1/3 of the patients)weight lossloss of strengthmalaise1.Crohns Disease Chapter 2 Inflammatory diseases 1.5 ComplicationsMain complications 肠梗阻一般急性且不可逆Obstruction: oc

28、curs as a result of chronic fibrosing lesions, which eventually narrow the lumen of the bowel, producing partial or near-complete obstruction. Perforation :Free perforations into the peritoneal cavity leading to a generalized peritonitis .but this presentation is rare. 穿孔慢性炎症，多发生粘连形成内瘘，故急性穿孔少见Other

29、complicationsfistulas :More commonly, occur between the sites of perforation and adjacent organs, such as loops of small and large intestine, the urinary bladder, the vagina, the stomach, and sometimes the skin, usually at the site of a previous laparotomy. Localized abscesses Toxic megacolon Coloni

30、c dilationFeverLeukocytosis 肛周疾病多见复杂性肛裂，反复发作肛瘘，应怀疑1.Crohns Disease Chapter 2 Inflammatory diseases Long-standing Crohns disease predisposes to cancer of both the small intestine and colon.The relative risk for adenocarcinoma of the small bowel in Crohns disease is at least 100-fold greater than in m

31、atched control subjects,and it more commonly occur in the ileum. Perianal disease 肛裂，肛瘘，肛周脓肿(fissure, fistula, or abscess) is common and occurs in 25% of patients with Crohns disease limited to the small intestine, 41% of patients with ileocolitis, and 48% of patients with colonic involvement alone.

32、 1.Crohns Disease可涉及全身各器官 Chapter 2 Inflammatory diseases Extraintestinal Manifestations of Crohns Disease:Skin :Erythema multiforme,Erythema nodosum,Pyoderma gangrenosum Eyes:Iritis,Uveitis,Conjunctivitis Joints:Peripheral arthritis,Ankylosing spondylitis Blood:Anemia,Thrombocytosis,Phlebothrombosi

33、s,Arterial thrombosis Liver :Nonspecific triaditis,Sclerosing cholangitis Kidney:Nephrotic syndrome,Amyloidosis Pancreas:Pancreatitis General :Amyloidosis 1.Crohns Disease Chapter 2 Inflammatory diseases Extraintestinal Manifestations of Crohns Disease:Erythema nodosum结节样红斑1.Crohns Disease Chapter 2

34、 Inflammatory diseases 1.6 DiagnosisPatients with chronic, recurring episodes of abdominal pain, diarrhea, and weight loss. Barium radiographic 钡餐studies of the small bowel reveal a number of characteristic findings, including a cobblestone appearance of the mucosa composed of linear ulcers, transve

35、rse sinuses, and clefts. Long lengths of narrowed terminal ileum 鹅卵石征，沟裂样深溃疡，临近窦道形成内瘘(Kantor string sign) may be present in long-standing disease . Fistulas between adjacent bowel loops and organs may be apparent . 节段性（跳跃性）腹痛可自行缓解，故多因并发症入院，梗阻，穿孔此时不能行钡餐1.Crohns Disease Chapter 2 Inflammatory diseases

36、 1.6 DiagnosisCT may be useful in demonstrating the marked transmural thickening, and it can also greatly aid in diagnosing extramural complications of Crohns disease .Ultrasonography has limited value in the evaluation of patients with Crohns disease .Sigmoidoscopy or colonoscopy may reveal charact

37、eristic aphthous ulcers with granularity and a normal-appearing surrounding mucosa When the colon is involved. 超声内镜仅限于结肠1.Crohns Disease Chapter 2 Inflammatory diseases 1.6 DiagnosisEndoscopic image of Crohns colitis showing deep ulceration1.Crohns Disease Chapter 2 Inflammatory diseases 1.6 Diagnos

38、isCT scan showing Crohns disease in the fundus of the stomach1.Crohns Disease Chapter 2 Inflammatory diseases 1.6 DiagnosisCrohns disease can mimic ulcerative colitis on endoscopy. This endoscopic image is of Crohns colitis showing diffuse loss of mucosal architecture, friability of mucosa in sigmoi

39、d colon and exudate on wall, all of which can be found with ulcerative colitis.1.Crohns Disease Chapter 2 Inflammatory diseases 1.6 DiagnosisEndoscopy image of colon showing serpiginous (葡行性）ulcer, a classic finding in Crohns disease1.Crohns Disease Chapter 2 Inflammatory diseases 1.6 DiagnosisEndos

40、copic image of colon cancer identified in the sigmoid colon on screening colonoscopy for Crohns disease.1.Crohns Disease Chapter 2 Inflammatory diseases 1.6 Differential diagnosis Bacterial inflammation, such as that caused by Salmonella and Shigella; Intestinal tuberculosis Protozoan infections, su

41、ch as amebiasis 1.Crohns Disease Table Diagnosis of Crohns Colitis Versus Ulcerative ColitisChapter 2 Inflammatory diseases 1.6 Differential diagnosis Crohns ColitisUlcerative ColitisDiarrheaCommonCommonRectal bleeding Less common Almost always Abdominal pain (cramps) Moderate to severe Mild to mode

42、rate Palpable mass 恶变At times 有时No (unless large cancer) Anal complications肛周并发症 Frequent (50%) Infrequent (20%) 1.Crohns Disease Table Diagnosis of Crohns Colitis Versus Ulcerative ColitisChapter 2 Inflammatory diseases 1.6 Differential diagnosis Radiologic FindingsCrohns ColitisUlcerative ColitisI

43、leal disease Common Rare (backwash ileitis) Ulcers Linear, cobblestone, fissures Collar-button （哑铃）Distribution Skip areas Rectum extending upward and continuously Toxic dilation RareUncommon末段1.Crohns Disease Table Diagnosis of Crohns Colitis Versus Ulcerative ColitisChapter 2 Inflammatory diseases

44、 1.6 Differential diagnosis Proctoscopic FindingsCrohns ColitisUlcerative ColitisAnal fissure, fistula, abscess CommonRareRectal sparing Common (50%)Rare (5%)Ulceration Linear, deep, scattered Superficial, universal 1.Crohns Disease Chapter 2 Inflammatory diseases 1.7 Management Medical Therapy Sali

45、cylazosulfapyridine (水杨酰偶氮磺胺吡啶）特效Antibiotics Immunosuppressive Agents （英夫利昔）免疫抑制剂注意适应症Nutritional Therapy Surgical TreatmentThe indications for operation are limited to complications that include :Intestinal obstructionIntestinal perforation with fistula formation or abscessFree perforationGastroint

46、estinal bleedingCancerPerianal disease 避免手术：吻合瘘口梗阻反复手术吻合瘘口2.Intestinal Tuberculosis肠结核 Chapter 2 Inflammatory diseases Tuberculosis is primarily a Lung Infection, but it can infect other areas of the body as well. Intestinal Tuberculosis frequently complicates Lung Infections with Tuberculosis. In a

47、ddition, milk, which contains tuberculi bacteria生牛奶, may also infect the intestine. 2.Intestinal Tuberculosis Chapter 2 Inflammatory diseases Pathophysiology:Routes of GI infection include the following: (1) Spread by means of the ingestion of infected sputum, in patients with active pulmonary TB an

48、d especially in patients with pulmonary cavitation;痰吞咽(2) Spread through a hematogenous route from tuberculous focus in the lung to submucosal lymph nodes; 血行细菌(3) Local spread from surrounding organs involved by primary tuberculous infection. 邻近器官2.Intestinal Tuberculosis Chapter 2 Inflammatory dis

49、eases Clinical features 不典型 May have not any symptom Fever Anorexia（厌食） Nausea Abdominal cramps in lower right abdomen Abdomen distends after eating进食后腹胀 Weight loss 2.Intestinal Tuberculosis Chapter 2 Inflammatory diseases Diagnosis: Mild right lower abdominal tenderness X-Rays may show colon irreg

50、ularities（不规则） Colonoscopy with biopsy may prove the diagnosis 2.Intestinal Tuberculosis Chapter 2 Inflammatory diseases Treatment: Medication: 抗痨治疗Anti-Tuberculosis medications in four drug combinations.Typical drugs include Isoniazid, Rifampin, Ethambutol, and Pyrazinamide for 6 to 9 months. Opera

51、tive Management:Accommodate:bowel obstruction、perforation、fistula肠套叠：常有基础性疾病，如肠壁脂肪瘤，炎症Chapter 3 Intestinal ObstructionDefinition:Interruption in the aboral passage of intestinal contents.Chapter 3 Intestinal ObstructionEtiology and Classify: Mechanical intestinal obstruction Dynamic intestinal obstr

52、uction Vascular ileusChapter 3 Intestinal ObstructionEtiology and Classify:Mechanical intestinal obstruction机械性梗阻:The causes of the obstruction can be divided into three categories :Chapter 3 Intestinal ObstructionEtiology and Classify:Mechanical intestinal obstruction:1. Intraluminal obturator obst

53、ruction (e.g. gallstones结石, ascarid蛔虫, foreign bodies异物)Chapter 3 Intestinal ObstructionEtiology and Classify:Mechanical intestinal obstruction:2. Obstruction arising from extraluminal causes such as adhesions粘连, hernias疝, Carcinomas（结肠）癌, and abscesses 脓肿Hernias AdhesionsChapter 3 Intestinal Obstru

54、ctionEtiology and Classify:Mechanical intestinal obstruction:3. Obstruction intrinsic to the bowel wall (e.g., primary tumors) :Inflammation tumourChapter 3 Intestinal ObstructionEtiology and Classify:Dynamic Intestinal Obstruction动力性肠梗阻不可手术paralytic ileus 麻痹性dynamic ileus 痉挛性 远端肠管先蠕动，同时收缩，假性梗阻Chapt

55、er 3 Intestinal ObstructionEtiology and Classify:Vascular Ileus血运性肠梗阻 积极手术Occluded SMA:Sudden occlusion of small bowel arterial supplyChapter 3 Intestinal ObstructionEtiology and Classify:Vascular Ileussimple intestinal obstruction单纯性 strangulated intestinal obstruction绞窄性Position of obstruction Upp

56、er高位 lower地位Degree of obstruction Complete完全 incomplete不完全Chapter 3 Intestinal ObstructionEtiology and Classify:Vascular IleusChapter 3 Intestinal ObstructionEtiology and Classify:Vascular IleusCommon Causes SBOChapter 3 Intestinal ObstructionPathophysiology Water 、electrolytes and acido-alkali unba

57、lance Infection and toxicosis Shock Respirtion and circulation function obstructionChapter 3 Intestinal ObstructionPathophysiologywater and electrolytes As the bowel dilates, water and electrolytes accumulate both intraluminally and in the bowel wall itself. This massive third-space fluid loss accou

58、nts for the dehydration and hypovolemia脱水和低血压. The metabolic effects of fluid loss depend on the site and duration of the obstruction. With a proximal obstruction, dehydration may be accompanied by hypochloremia低氯, hypokalemia低钾, and metabolic alkalosis代碱 associated with increased vomiting. Chapter

59、3 Intestinal ObstructionPathophysiologywater and electrolytes Distal obstruction of the small bowel may result in large quantities of intestinal fluid into the bowel; Oliguria（少尿）, azotemia（氮质血症）, hemoconcentration（血浓缩） can accompany the dehydration. Hypotension and shock can ensue. Other consequenc

60、es of bowel obstruction include increased intra-abdominal pressure, decreased venous return, and elevation of the diaphragm, compromising ventilation. These factors can serve to further potentiate the effects of hypovolemia.Chapter 3 Intestinal ObstructionPathophysiologyperforation and peritonitisAs