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Karteikarten

GI surgery 3

Rachael Jones 4. Gastrointestinal Englisch 66 Karten

Karten in diesem Stapel (66)

  1. 1What is the normal GI tract of the horse?- Stomach
    - Duodenum
    - Jejunum
    - Ileum
    - Caecum
    - Right ventral colon
    - Sternal flexure
    - Left ventral colon
    - Pelvic flexure
    - Left dorsal colon
    - Diaphragmatic flexure
    - Right dorsal colon
    - Transverse colon
    - Small colon
    - Rectum
  2. 2How is the caecum located?Base is caudally
    - Apex in cranially
    - On the right side mainly
  3. 3What is the main feature of the jejunum?On a long mesentery so can result in herniation etc.
  4. 4Why is it important to know the location of the different sections of the GI tract?Can be displaced due to different conditions
    - Have to know how to correct and therefore the normal location
  5. 5What is the main concern with the colon in the abdomen?Mainly free to move - leads to displacements
  6. 6What do the main surgical diseases of the large bowel consist of?- Displacements of the colon from its normal position
  7. 7What can displacements lead to?Colon frequently becomes distended with gas/fluid due to continued fermentation in the presence of obstruction
  8. 8What does surgical management of colonic displacements involve?- Recognising the nature of the displacement (not always easy)
    - Decompression of distended bowel (needle and suction for gas)
    - Evacuation of the colon via a pelvic flexure enterotomy may be necessary if distention is with fluid/food
    - Correction of the displacement
    - Resections are rarely necessary and technically challenging
    - Colopexy (anchoring the colon by suturing eg to the body wall) is occasionally performed in non athletes to prevent recurrence.
  9. 9What is found with most displacements?Non- strangulating
  10. 10What is an exception to the non- strangulating rule?Colonic torsion
  11. 11What is a nephrosplenic entrapment?- Left dorsal displacement of the colon over the spleen
  12. 12What occurs in a nephrosplenic entrapment (NSE)?- The left dorsal and ventral colons migrate dorsal and lateral to the spleen and become entrapped in the nephrosplenic space
    - The weight of the colon causes the spleen to displace medially and ventrally and to become congested, and the left colon can become impacted because of impaired flow of ingesta over time.
  13. 13What types of horses are more typically affected by NSE?Mature performance horses ages 4-8 years
  14. 14What can occur in the NSE progression?Left dorsal displacement starts as a nonstrangulating lesion of the large colon; however, when the duration of the condition increases to longer than 24 h, colonic congestion and oedema can develop and potentially lead to mural damage
  15. 15What is the pathophysiolocal mechanism for NSE?Unknown; however, it is theorised that excessive gas formation within the left colon, perhaps associated with altered colonic motility, causes the left colon to displace laterally to the spleen and dorsally into the nephrosplenic space
  16. 16What can be palpated per rectum in NSE?- Spleen displaced ventrally and medially
    - Left colon heading dorsally
  17. 17How do you diagnose NSE?Based on rectal palpation and ultrasonographic examination
  18. 18What is the pain associated with NSE?Mild to severe depending on the location of the colon, the amount of gas distension, and the presence of secondary gastric distension
  19. 19What is seen on abdominal ultrasound with NSE?Left kidney is often impossible to visualise axial to the spleen because of the presence of a gas-filled colon that obscures the view
  20. 20What is felt with rectal palpation with NSE?The left colon is most often gas distended, or sometimes impacted, and can be traced up into the nephrosplenic space
  21. 21What are the treatment options for NSE?- Medical therapy with analgesia, i.v. and oral fluids and feed restriction,
    - Exercise (eg lunging) with or without administration of phenylephrine,
    - “Rolling” - under general anaesthesia with or without administration of phenylephrine,
    - Standing flank laparotomy,
    - Ventral midline celiotomy under general anaesthesia
  22. 22Why is phenylephrine used for NSE?Phenylephrine, an α-1 adrenergic receptor agonist, may be used as part of medical management to cause splenic contraction and facilitate correction.
  23. 23What are the side effects of phenylephrine?- Bradycardia, hypertension, second-degree atrioventricular blocks, and premature ventricular contractions but these are not usually serious.
    - Phenylephrine-associated haemorrhage is possible and may result in death.
  24. 24What can be a successful treatment of NSE when done early in the disease?Vigorous exercise (eg lunging) in association with phenylephrine
  25. 25How can rolling be used to treat NSE?- The procedure is performed under general anaesthesia.
    - The horse is initially positioned in right lateral recumbency, then in dorsal recumbency.
    - The operator(s) shake the horse vigorously for 1–2 min, and then the horse is lowered to left lateral recumbency on the floor.
    - At this point, the horse is rolled into sternal recumbency and then into right lateral recumbency again.
    - palpation per rectum can be performed on the recumbent horse to try to establish if correction has occurred,
    - the rolling procedure may be repeated if necessary
  26. 26When is surgical correction of NSE required?If medical management or nonsurgical manipulations are unsuccessful, or if pain cannot be controlled or cardiovascular parameters deteriorate
  27. 27What is the surgical correction for NSE?- Standing flank laparotomy may be performed
    - Ventral midline laparotomy under general anaesthesia is most commonly performed: ensures successful correction and allows detection of concurrent undiagnosed problems
  28. 28What is the recurrence of NSE?3.2% to 21% regardless of treatment chosen
  29. 29What can be done to manage the prevention of NSE?Good management of the horse's nutrition, exercise and turnout routine, dental treatment and deworming schedule, as well as avoidance of sudden changes of feed or housing, may aid in the prevention of left dorsal displacement as well as other large colon simple obstructions
  30. 30What are the surgical procedures that have been advocated for prevention of reccurrence of NSE?- Ablation of the nephrosplenic space,
    - Colopexy
    - Large colon resection
  31. 31What occurs in a right dorsal displacement of the colon?- Right dorsal displacement may be initiated by im­paction at the pelvic flexure, which causes the pelvic flexure to displace cranially.
    - The left and right ventral colons then distend with gas and flip caudally ventral to the cecum.
    - As a result, the right ventral and right dorsal portions of the colon twist on themselves near the base of the cecum, and the pelvic flexure ends up near the diaphragm
  32. 32What are the effects of right dorsal displacement on the colon?- May be some interference with venous drainage from the affected colon, usually the arterial supply remains intact
  33. 33What is seen with right dorsal displacement of the colon?- Exhibit moderate degrees of pain and slowly become dehydrated.
    - The degree of pain correlates with the degree of gas distention of the colon
  34. 34How is right dorsal displacement identified?During the rectal examination when the bands on the distended colon running transversely across the pelvic inlet are palpated, and the cecum cannot be identified
  35. 35How can right dorsal displacement of the colon be treated if only mild pain and no evidence of gas?Food can be withheld to see if natural evacuation of the intestinal contents allows the colon to return to its normal position
  36. 36How can right dorsal displacement of the colon be treated if severe pain?- Surgery must be performed. The pelvic flexure must be identified and the colon relocated to its normal position by rotating it around the caecal base.
    - Manipulation may be difficult because of the degree of displacement and size of the colon. Consequently, a large ventral midline incision often is necessary
  37. 37What is the prognosis for surgical treatment of right dorsal displacement?Good provided care is used to ensure that the colonic wall is not damaged during surgery
  38. 38Where is the pelvic flexure located in right dorsal displacement?Near the diaphragm
  39. 39What happens in a large colon volvulus?Twists on the long axis
  40. 40What occurs in a large colon volvulus?- Most critical problem affecting the horse's large colon because it is commonly a strangulating obstruction with ischaemia of a huge section of the horse’s GI tract.
    - The volvulus may occur at the sternal flexure or close to the attachment of the right ventral colon to the cecum and results in a great deal of gas distention of the affected colon
  41. 41What is the cause of large colon volvulus?Unknown
  42. 42What horses are more likely to be affected by large colon volvulus?Larger horses rather than ponies and is particularly seen in brood mares about 90 days after foaling.
  43. 43What is seen in large colon volvulus?- The onset of abdominal pain is sudden, and the degree of pain is often severe. The colon becomes extremely enlarged and very evident on rectal examination. Distention of the abdomen usually is marked.
    - Mucosal ischaemia leads to endotoxaemia and the animal’s systemic status deteriorates rapidly. The heart rate is high and there is poor peripheral perfusion.
  44. 44What is required to treat large colon volvulus?- Surgery to correct problem and remove ischemic colon
  45. 45What is the prognosis of large colon volvulus?- Directly related to the time that elapses between onset of the condition and surgery.
    - As a result, survival rates exceeding 90% are common for veterinary surgical facilities located near brood mare farms,
    - Much lower survival rates are reported when horses must be transported several hours to a surgical facility.
  46. 46What can be seen distal to where the volvulus occurs?Ischaemia and necrosis
  47. 47Where can you incise to empty the large colon?Pelvic flexure as can be exteriorised from the abdomen
  48. 48What are features of caecal impaction?- Variable consistency of contents
    - Mild to moderate pain
    - May occur as a post-surgical complication
    - Tx by oral and iv fluids, analgesics, gentle exercise
    - Rupture of the caecum as a consequence of impaction has been reported
  49. 49What can happen with caecal and caecocolic intussuception?- Starts when tip of caecum invaginates into body. May be visible on ultrasound.
    - Initially can be reduced manually
    - In more severe cases the caecum can invaginate through into the colon
    - In that situation the oedematous ischaemic apex of the caecum may require resection within the right ventral colon before reduction
  50. 50What can be the risk during surgery for intussuception?Risk of abdominal contamination during
  51. 51What can intussuceptions be associated with?Anoplocephala (tapeworm) infestation
  52. 52What are enteroliths?Mineralised concretions of food material
  53. 53Where may enteroliths cause obstructions?Where large intestine narrows:
    - Transverse colon
    - Pelvic flexure
    - Small colon
  54. 54Are enteroliths common?No - rare in Europe
    More common in USA
  55. 55When are rectal tears likely to happen?During rectal examination
  56. 56Where are rectal tears usually found and what does this suggest?Tear is often dorsal and more likely due to contraction of rectum on hand rather than poking a finger through yourself – rectal tears do not in the vast majority of cases constitute negligence on your part.
  57. 57What is the usual way of diagnosing a rectal tear?Blood on rectal sleeve when hand withdrawn from rectum
  58. 58What should you do if you see blood on rectal sleeve?- Sedate horse and give spasmolytics (eg “Buscopan”) – consider epidural
    - Further palpation (easiest with an ungloved hand) to remove any faeces and confirm existence and depth of tear – consider endoscopy
    - TELL OWNER
    - Often wise to consider referral for a second opinion
  59. 59How are rectal tears graded?Graded in severity according to depth
    Grade 1) Involves the mucosa only.
    Grade 2) Mucosal and submucosal tears.
    Grade 3) Tears involving the muscularis. Only the serosa is intact.
    Grade 4) Complete tear with leakage of faecal material into the abdomen
  60. 60In reality what matters about the depth of rectal tears?- Full thickness or not
    - Full = faecal material into abdomen/ dead horse
    - Not = conservative treatment/ live horse
  61. 61How can incomplete tears be treated?Managed conservatively with starvation, followed by a laxative diet and antimicrobial cover – reasonably good prognosis
  62. 62At what grade is euthanasia required?Grade 4
  63. 63What can be done for grade 3 tears?Variety of surgical interventions for suturing and by-pass of complete (and grade 3) rectal tears have been described
  64. 64What are the downsides to the surgical interventions?- Access to suture either at laparotomy or per rectum is extremely limited
    - By-pass techniques such as colostomy have significant complications
    - It is known that grade 3 tears can be successfully managed conservatively though some will progress to grade 4
  65. 65What is required if attempting treatment of complete tears?Packing the rectum with a “tube” of antiseptic soaked bandage material to try to prevent further leakage of faeces and abdominal contamination
  66. 66How do you prevent rectal tears?Appropriate restraint of horse for rectal examination (consider spasmolytics) and careful technique – don’t resist rectal contractions

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4. Gastrointestinal (Equine Gastrointestinal Surgery - Alistair Barr) Karteikarten am GI surgery 3, erstellt von Rachael Jones am 31/10/2018.
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