Mesentry and omenum.pptx

Lecture notes for medical students

1. Tips on using my ppt. You can freely download, edit, modify and put your name etc. Don’t be concerned about number of slides. Half the slides are blanks except for the title. First show the blank slides (eg. Aetiology ) > Ask students what they already know about ethology of today's topic. > Then show next slide which enumerates aetiologies. At the end rerun the show – show blank> ask questions > show next slide. This will be an ACTIVE LEARNING SESSION x three revisions. Good for self study also. See notes for bibliography.

2. Mesentry and omentum

3. Mesentry and omentum Anatomy and Surgical Disorders

4. - -

5. Anatomy of omentum 1- Omenta : Broad peritoneal sheet associated with stomach are termed omemta. Two omenta Lesser omentum Greater omentum

6. - Lesser omentum T wo-layered fold of peritoneum Passes from the lesser curvature of the stomach and first part of the duodenum to the inferior surface of the liver. Extends from porta hepatis, fissure of ligamentum venosum and the diaphragm to lesser curvature of stomach and superior part of duodenum

7. Lesser omentum Hepatogastric ligament from porta hepatis to lesser curvature of stomach Hepatoduodenal ligament - Extends from porta hepatis to superior part of duodenum, - at its free margine enclose 3 structures(3 key structures) common bile duct  Ant. proper hepatic a  At the Lt. of the common bile duct portal v  post.

8. - Contents of lesser omentum

9. - Blood vessels  Rt. & Lt. gastric vessels Lymph nodes & lymphatic vessels Fat Autonomic N.S  sympathetic + parasympathetic (vagus nerve) Contents of lesser omentum

10. - Greater omentum It is the largest peritoneal fold. It consists of a double sheet, folded on itself so that it is made up of four layers. The anterior two layers descend from the greater curvature of stomach and superior part of duodenum and hangs down like an apron in front of coils of small intestine then turn up on the back of itself, and ascend to the transverse colon . - the two layers are separated to cover the anterior and posterior surfaces of transverse colon. Then they form the transverse mesocolon

11. - The upper part of the greater omentum which extends between the stomach and the transverse colon is termed the gastrocolic ligament . In adult, the four layers of greater omentum are frequently adhered together, and are found wrapped about the organs in the upper part of the abdomen

12. - Contents of Greater omentum (between the descended layers)

13. - Contents of Greater omentum (between the descended layers) Gastroepiploic vessels Lymph nodes & lymphatic vessels Fat Autonomic N.S  sympathetic + parasympathetic (vagus nerve)

14. - Functions of greater omentum

15. - ① protective function : The greater omentum contains numerous fixed macrophages, which performs an important protective function. ② storehouse for fat : The greater omentum is usually thin, and presents a cribriform apperarance, but always contains some adipose tissue, which in fatty people is present in considerable quantity. ③ migration and limation : The greater omentum may limit spread of infection in the peritoneal cavity. Because it will migrate to the site of any inflammation in the peritoneal cavity and wrap itself around such a site, the greater omentum is commonly referred to as the “policeman” of the peritoneal cavity. Functions of greater omentum

16. -

17. MESENTERY

18. MESENTERY Mesentery = double layer of peritoneum created by invagination of peritoneum by an organ Is the continuity of visceral and parietal peritoneum Provides a pathway for neurovascular communication between organ and body wall Contains lymph nodes and variable amounts of fat The mesentery  is the mesentery of the small intestine The  mesocolon  is the mesentery of the large intestine Transverse mesocolon Sigmoid mesocolon

19. - 1- Mesentery of small intestine - suspends the small intestine from the posterior abdominal wall -Broad and a fan-shaped Root of mesentery 15 cm long Directed obliquely from left side of L2 vertebra to right sacroiliac joint

20. - Mesentery of small intestine….cont Contents of the mesentery the jejunal and ileal branches of the superior mesenteric artery &veins nerve plexuses lymphatic vessels the lymphatic nodes, connective tissue fat

21. - 2- Mesoappendix Triangular mesentery － extends from terminal part of ileum to appendix Appendicular artery runs in free margin of the mesoappendix

22. - 3. The transverse mesocolon It is a broad fold Connects the transverse colon to the anterior border of the pancreas. Contents - The blood vessels - Nerves - lymphatic's of the transverse colon.

23. - 4- Sigmoid mesocolon - It is a fold of peritoneum attaches the sigmoid colon to the pelvic wall. Contents The sigmoid vessels Lymphatic vessels Nerves The left Ureter descends into the pelvis behind its apex.

24. - - A wound of the mesentery can follow a severe abdominal contusion and is a cause of haemoperitone um. Conditions of the mesentery Traumatic tears Torsion •Embolism/thrombosis •Acute non-specific adenitis •Tuberculosis adenitis •Cysts •Neoplasms - benign and malignant •

25. Acute non-specific ileocaecal mesenteric adenitis Aetiology very much more common than the tuberculous variety. aetiology often remains unknown, although some cases are associated with Yersinia infection of the ileum. In other cases, an unidentified virus is blamed. In about 25% of cases, a respiratory infection precedes an attack of non-specific mesenteric adenitis. This self-limiting disease is never fatal but may be recurrent.

26. Pathology small increase in amount of peritoneal fluid. ileocaecal mesenteric lymph nodes are enlarged In very acute cases - distinctly red, many of them are size of a walnut. Nodes nearest the attachment of the mesentery are the largest. Not adherent to their peritoneal coats, and if a small incision is made through the overlying peritoneum a node is extruded easily.

27. During childhood, acute non- specific common condition. unusual after puberty sometimes seen in teenage girls. Typical history is one of short attacks of central abdominal pain lasting from 10 to 30 minutes, and associated with circumoral pallor. They tend to come on when the patient is tired. Vomiting is common but there is no alteration of bowel habit. If vomiting is absent, it is more likely to be a case of mesenteric adenitis than appendicitis.

28. History

29. History Onset and progression may be insidious or sometimes dramatic. Clinical features of associated organ involvement, such as enterocolitis or ileitis in  Yersinia infection, may be present. Clinical presentations include the following: Abdominal pain - Often right lower quadrant (RLQ) but may be more diffuse Fever Diarrhea Malaise Anorexia Concomitant or antecedent upper respiratory tract infection Nausea and vomiting (which generally precedes abdominal pain, as compared to the sequence in appendicitis) History of ingestion of raw pork may be obtained in areas with endemic Yersinia  (eg, Belgium).

30. Physical

31. Physical No set of physical findings is pathognomonic of mesenteric lymphadenitis. Fever (38-38.5°C) Flushed appearance RLQ tenderness - Mild, with or without rebound tenderness Voluntary guarding rather than abdominal rigidity Rectal tenderness Rhinorrhea Hyperemic pharynx Toxic appearance Associated peripheral lymphadenopathy (usually cervical) in 20% of cases

32. Differential Diagnoses Appendicitis Benign Neoplasm of the Small Intestine Cholecystitis Chronic Mesenteric Ischemia Ectopic Pregnancy Inflammatory Bowel Disease Pyelonephritis, Acute Salpingitis Urinary Tract Infection, Females Urinary Tract Infection, Males

33. Laboratory Studies CBC count: Leucocytosis with WBCs exceeding 10,000/µL occurs in at least 50% of cases. Chemistries: - Findings are generally within reference ranges except in patients with severe nausea and vomiting who may present with metabolic alkalosis and azotemia. Serology can be supportive in diagnosis of etiologic agents such as   Y enterocolitica.   Serological tests tend to be delayed, and several antigens may have to be tested. Urinalysis may be useful to perform when the diagnosis is unclear and to exclude urinary tract infection. In patients who present with diarrheal symptoms, stool cultures should be performed. Blood culture: This is performed prior to prescribing antibiotics and in patients who have features of septicemia. Isolation of the organism from blood, lymph nodes, or other body fluids will help define appropriate therapy and guide further evaluation.

34. Imaging Studies

35. Imaging Studies Contrast computed tomography (CT) demonstrates enlarged mesenteric lymph nodes, with or without associated ileal or ileocecal wall thickening, and a normal appearing appendix. In mesenteric adenitis, lymph nodes tend to be larger, greater in number, and more widely distributed than in appendicitis. Rao et al specified the criterion of 3 or more nodes with a short-axis diameter of at least 5 clustered in the right lower quadrant. CT scanning is also important to exclude other differential diagnoses, especially acute appendicitis.

36. Abdominal ultrasound scanning with Doppler scanning is a useful adjunct for excluding other differential diagnoses.   For instance, ultrasonic demonstration of mural thickening of the terminal ileum plus mesenteric thickening is indicative of regional enteritis. Focal abdominal tenderness in response to transducer pressure is common. Ultrasound is often the preferred initial diagnostic procedure, especially in children with uncomplicated abdominal pain.

37. Tuberculosis of the mesenteric lymph nodes

38. Tuberculosis of the mesenteric lymph nodes Tuberculous mesenteric lymphadenitis less common than acute non-specific lymphadenitis. Tubercle bacilli, usually, but not necessarily, bovine, are ingested and enter the mesenteric lymph nodes by way of Peyer's patches. It is possible for one draught of raw milk to start the infection; it is equally possible that a toddler can become infected with human tubercule bacilli by placing one dust-covered small object in its mouth. Sometimes only one lymph node is infected; usually there are several; occasionally massive involvement occurs

39. Tuberculosis of Mesenteric Lymph Nodes Isolated involvement of the mesentry in tuberculosis is uncommon. Usually there is concomitant involvement of the bowel or peritoneum, or more commonly, both. The patient will give a history of previous pulmonary tuberculosis or is currently on treatment. Ingested tubercle bacilli reach the Peyer's patches in the bowel and involvement of bowel. This gives rise to the involvement of the mesenteric nodes. Usually several lymph nodes are involved. Involvement of the bowel and the peritoneum is also seen.

40. Clinical presentation

41. Clinical presentation Asymptomatic: The patient is asymptomatic with a calcified lymph node seen on X-ray.   Toxemia: The patient presents with symptoms of tubercular toxemia with evening pyrexia, pallor, and anorexia and weight loss. Very often, abdominal pain is present due the the involvement of the bowel. Abdominal mass: Several matted lymph nodes in the right iliac fossa will give the appearance of a mass. This may be confused with an appendicular mass or a carcinoma.   Intestinal obstruction: Subacute obstruction may be present due to the involvement of the ileocecal region of the bowel.  

42. Investigations

43. Investigations Plain X-ray of the abdomen: It may show a calcified opacity similar to a ureteric calculus. US abdomen should be performed in the presence of a mass in the right iliac fossa. Multiple matted lymph nodes are clearly seen. In cases of involvement of the bowel, dilated and thickened loops may be demonstrated.  

44. Barium meal follow-through: When bowel involvement is suspected, the patient presents with subacute obstruction .

45. T/t

46. T/t Anti-tubercular treatment (ATT): Treatment is by a full course of antituberculosis chemotherapy. ATT should be started with four antituberculous drugs for two months (HRZE) and at least two of these (HR) are continued for at least 4 months. Laparotomy : It is indicated in the presence of subacute intestinal obstruction due to involvement of the ileocecal region. Sometimes, the matted loops may cause a compression over the ileocecal region along with contiguous involvement. In such case, an ileotransverse anastomosis may be performed. Any adhesions are lysed and limited right hemicolectomy is performed for involvement of the ileocecal region.

47. Mesenteric Trauma (Tears) Mesenteric vessels injured by penetrating or blunt trauma of the abdomen. Tear of the mesentery with laceration of the vessel. In penetrating injuries of the mesenteric vessels, associated injury to other organs is frequent. Transverse tears carry more morbidity as they often lead to damage of vascularity of the bowel unlike longitudinal tears.

48. Clinical features

49. Clinical features The patient will present with shock, abdominal pain, tenderness distention. This depends on the severity of injury and associated injuries .

50. - - Treatment Exploratory laparotomy Gunshot wounds of abdomen most stab wounds should be explored early. Longitudinal tears are apposed after securing hemostasis but Transverse tears often require resection and anastomosis of a segment of the bowel due to devitalization. Lacerations of the mesenteric veins can be ligated. Injury to the main trunk of the superior mesenteric artery, primary suture or interposition of a vascular graft between the severed ends of the vessel should be attempted.

51. - mesentric cyst

52. - mesentric cyst Mesenteric cysts can occur anywhere in the mesentery of gastrointestinal tract from duodenum to rectum, may extend from the base of the mesentery into the retroperitoneum . 60% in the small-bowel mesentery, 24% in the large-bowel mesentery, 14.5% in the retroperitoneum . They most commonly occur in the ileal mesentery of the small bowel or the sigmoid mesentery of the colon.

53. Mesenteric cysts are of following type a ) Chylolymphatic (most common) Enterogenous Urogenital remnant d) Dermoid ( teratomatous cyst)

54. Chylolymphatic cyst

55. Chylolymphatic cyst Usually are congenital, resulting from developmental sequestration of lymphatics. It is found most frequently in the mesentery of the ileum. Cyst wall is thin, made up of connective tissue; lacks the muscular wall of enteric duplication cyst Cyst is not lined by mucosa. It is filled with clear lymph or chyle. A chylolymphatic cyst is almost invariably solitary, although in extreme rare cases, multiple cyst may be seen. Cyst is more often unilocular than multilocular. A chylolymphatic cyst has a blood supply independent of that of the adjacent intestine, and thus enucleation (resection) is possible without the need for resection of gut.

56. Enterogenous Cyst

57. Enterogenous Cyst Believed to be derived either from a diverticulum of the mesenteric border of the intestine which has become sequestered from the intestinal canal during embryonic life or from a duplication of the intestine. An enterogenous cyst has thicker wall than a chylolymphatic cyst, and it is lined by mucous membrane, sometimes ciliated. The content is mucinous The enterogenous cyst and the adjacent bowel wall has a common blood supply therefore enucleation of the cyst is always done along with resection of the related portion of intestine followed by anastomosis.

58. Clinical features

59. Clinical features a) a painless abdominal swelling, the swelling moves freely in a plane at right angles to the attachment of the mesentry. b) recurrent attacks of abdominal pain with or without vomiting due to obstructive symptoms. c) acute abdominal pain due to torsion of the mesentry containing cyst rupture of cyst haemorrhage into the cyst infection of the cyst

60. t/t

61. t/t Enucleation ls the t/t of choice. Associated segment of bowel is removed along with enterogenous cyst. Other tit modalities i.e. marsupialization, internal drainage, or aspiration are suboptimal and are almost always followed by recurrence.

62. Acute Mesenteric ischemia • This pt. is having ischemia of various organs due to atherosclerotic narrowing of arteries. • Ischemia of Brain -----> CVA (stroke) • Ischemia of Heart -----> Myocardial infarction • Ischemia of Intestines ----->

63. Etiology- (A) Sudden Occlusion of the superior mesentric artery (50%)* Cause - Atherosclerosis * (90%)* Embolism * Vasculitis (PAN) * Fibromuscular dysplasia of mesentric artery* ( B) Mesentric vein occlusion (25%) Cause - • Thrombosis in hypercoaguable states such as polycythemia vera, * OCp* use • Infiltration by malignant neoplasm. (C) Nonocclusive infarction (25%) • Intestinal infarction may occur without physical obstruction of the mesentric arteries in severe shock where there is prolonged vasoconstriction in the intestinal arterial circulation.

64. • Pathology:

65. • Pathology: • Transmural necrosis of the intestinal wall. This is rapidly followed by bacterial infection from the lumen and acute inflammation leading to wet gangrene*. Both arterial and venous occlusion lead to haemorrhagic infarction" and distinction cannot be made on examination of bowel.

66. Clinical features

67. Clinical features AMI is characterized by a sudden onset of severe abdominal pain (often colicky and periumbilical at the onset ,later becoming diffuse and constant ). fever; anorexia,vomiting and constipation frequent. Examination of abdomen may reveal tenderness & abdominal distention. There is functional intestinal obstruction with absent bowel sounds. Bloody diarrhoea may occur. • The disease progresses very rapidly with shock and peritonitis due to bacterial permeation of the necrotic bowel wall. • Without operation there is 100% mortality. Even with emergency surgery the mortality rate remains high .

68. Abdominal plain films –reveal air – fluid levels and distension. Barium study of small intestine-non specific dilation,poor motility,evidence of thick mucosal folds. Arteriography is diagnostic. Embolectomy is t/t

69. Omental Cysts Cysts of the omentum are rare. True cysts : These are caused by obstruction of lymphatic channels . They may be unilocular or multilocular and contain serous fluid. True cysts have an endothelial lining and may assume large sizes. Dermoid cysts are uncommon and are lined with squamous epithelium and may contain hair, teeth, and sebaceous material. False cysts: Pseudocyst of the omentum result from fat necrosis, trauma with hematoma, or foreign-body reaction. These have a fibrous and inflammatory lining and usually contain cloudy or blood-tinged fluid .

70. Abdominal mass: Large cysts present as a palpable abdominal mass or produce diffuse abdominal swelling. The uncomplicated omental cyst usually lies in the lower midabdomen and is freely movable, smooth, and nontender . These may cause symptoms of heaviness or pain or manifestations of possible complications of omental cysts such as torsion, infection, rupture, or intestinal obstruction.

71. Investigations Plain X-ray of the abdomen: It may show a soft tissue haziness. The presence of bone or teeth is diagnostic of dermoid cyst. Barium meal follow-through: It will demonstrate a displacement of bowel loops. Ultrasound or CT scan: It shows a fluid-filled mass that often contains internal septations .

72. Treatment

73. Treatment laparotomy and excision of the cyst should be performed.

74. - Torsion of Omentum

75. - Torsion of Omentum uncommon condition in which the organ twists on its long axis, causing vascular compromise . This may vary from mild vascular constriction to complete strangulation leading to frank gangrene.

76. -ETIOLOGY

77. -ETIOLOGY The omentum twists around a fixed point commonly due to adhesions of the free end of the omentum due to postoperative wounds, scarring internal or external hernias.

78. - Clinical features

79. - Clinical features Pain is the initial and predominant symptom. The onset of pain is sudden and constant and increases in severity.

80. Investigations

81. Investigations CT scan may be of some use in diagnosing omental pathology.

82. Treatment

83. Treatment It consists of resection of the involved omentum . In patients with torsion, the underlying condition (hernia, cysts, adhesions,) should be corrected.

84. Uses of Omentum

85. Uses of Omentum Intraabdominal : Repair of vesicovaginal and vesicocolic fistulas Augmentation of bowel anastamoses Augmentation of wound closures involving the urinary bladder Repair of defects of the abdominal wall

86. Uses of Omentum Extraabdominal : Support of primary suture lines of the esophagus Closure of full-thickness defects of the esophagus Repair of thoracic wall defects Palliation of lymphedema of an extremity Revasularization of tissue that is ischemic -brain of stroke victims -myocardial ischemia - non-healing wounds of the skin Resurface scalp defects Reconstruct facial deformities Repair of bronchopleural fistulas Uses reported in literature (veterinary) Intraabdominal : Augment intestinal surgery wounds ( enterotomy , end-to-end anastomosis ) Prostatic abscesses and cysts Augment urinary bladder incision lines Pancreatic abscesses Liver biopsy sites Extraabddominal : Thoracic wall defects created by “en-bloc” excision of rib tumors /abscesses

87. Uses of Omentum Extraabdominal : contd. Resurface scalp defects Reconstruct facial deformities Repair of bronchopleural fistulas

88. MCQ

89. MCQ 1..Which one of the following is not correct regarding chylolymphatic cyst ? (UPSC/03) (a) It does not contain chyle very frequently (b) Enucleation is impossible because blood supply is same as that of the adjacent intestine (c) It is the commonest mesenteric cyst (d) It is lined by endothelium and has no different lymphatic communications

90. 1..Which one of the following is not correct regarding chylolymphatic cyst ? (UPSC/03) (a) It does not contain chyle very frequently (b) Enucleation is impossible because blood supply is same as that of the adjacent intestine (c) It is the commonest mesenteric cyst (d) It is lined by endothelium and has no different lymphatic communications

91. 2.Most common type of mesenteric cyst is: (AIIMS 93 ,KARNATAKA 2008) Enterogenous (b) Chylolymphatic (c) Dermoid (d) Urogenital remnant

92. 2.Most common type of mesenteric cyst is: (AIIMS 93, KARNATAKA 2008) Enterogenous ( b) Chylolymphatic (c) Dermoid (d) Urogenital remnant

93. 3.Which is mesenteric cyst whose removal entrails removal of part of gut: Chylolymphatic cyst (b) Enterogenous cyst (c) Dermoid (d) All

94. 3.Which is mesenteric cyst whose removal entrails removal of part of gut: Chylolymphatic cyst (b) Enterogenous cyst (c) Dermoid (d) All

95. 3.Mesenteric cysts A/E (DNB Dec 07) A. Chylolymphatic B. Urogenital remnant C. Dermoid cyst D. Calcified lesion

96. 3.Mesenteric cysts A/E (DNB Dec 07) A. Chylolymphatic B. Urogenital remnant C. Dermoid cyst D. Calcified lesion

97. 4.All the following are feature of Mesenteric cyst except (JI P -1993) (a) common in infants (b) swelling near umbilicus (c) painless swelling (d) can present as acute abdomen

98. 4.All the following are feature of Mesenteric cyst except (JIP -1993) (a ) common in infants (b) swelling near umbilicus (c) painless swelling (d) can present as acute abdomen

99. 5.True about mesenteric cyst: (PGI 97) Enterogenous cyst is the most common variety (b) Mesenteric cyst are usually multiple (c) Enucleation is the treatment of choice of chylolymphatic cyst (d) Recurrence is common after enucleation

100. 5.True about mesenteric cyst: (PGI 97) Enterogenous cyst is the most common variety (b) Mesenteric cyst are usually multiple (c) Enucleation is the treatment of choice of chylolymphatic cyst (d) Recurrence is common after enucleation

101. 6.Mesenteric cyst" (AI 98) Moves parallel to the mysentery Moves perpendicular to the mesentery Is secondary tumour Is fixed and immobile

102. 6.Mesenteric cyst" (AI 98) Moves parallel to the mysentery Moves perpendicular to the mesentery Is secondary tumour Is fixed and immobile

103. 7.Commonest cuase of acute mesentric adenitis is (JIPMER 81, AMU87) a) Tuberculosis b) Brucellosis c) Pneumococcal infection d) Idiopathic  

104. 7.Commonest cuase of acute mesentric adenitis is (JIPMER 81, AMU87) a) Tuberculosis b) Brucellosis c) Pneumococcal infection d) Idiopathic

105. 8.Most common cause of mesenteric ischemia? (AIIMS Nov 08) A. Embolism B. Non-occlusive ischemia C. Arterial thrombosis D. Venous thrombosis

106. 8.Most common cause of mesenteric ischemia? (AIIMS Nov 08) A. Embolism B. Non-occlusive ischemia C. Arterial thrombosis D. Venous thrombosis

107. 9.True about mesenteric vein thrombosis ‑ (PGI DEC 2000) Peritoneal signs are always present Invariably involves long length of bowel I.V. Heparin is the treatment of choice Surgery can lead to short-bowel syndrome

108. 9.True about mesenteric vein thrombosis ‑ (PGI DEC 2000) Peritoneal signs are always present Invariably involves long length of bowel I.V. Heparin is the treatment of choice Surgery can lead to short-bowel syndrome

109. 10.Mesenteric tumors are a) Usually solid. b) Usually cystic c) Highly malignant. d) Highly vascular

110. 10.Mesenteric tumors are a) Usually solid. b) Usually cystic c) Highly malignant. d) Highly vascular

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