Disorders of Small and Large Bowel

1. Disorders of Small and Large Bowel Jay Green October 26, 2006

2. Case 1 • 54 y.o. F, abdominal pain • Started 2 days ago, shortly after Big Mac • Hurts all over, comes and goes, crampy • +D yesterday, bloated, +N today, ø V • PMH: DMII, HTN, TAH/BSO (’04) • Ideas?

3. DDx - Approach • Think anatomy Intraperitonaeal, retroperitoneal, other • Think VITAMIN D, VINDICATED, whatever… • Vascular • Ischemic gut, MI, AAA • Infection • Gastro, PUD, psoas abscess • Neoplastic • Intussusception • Inflammatory • Diverticulitis, Cholecystitis, Pancreatitis, Appendicitis • Traumatic • Obstruction • Pregnancy

5. Small Bowel Obstruction • Top 3 causes? • Hernia • Adhesions • CA • Most likely to cause strangulation? • Hernia – often closed loop • Others to think about? • Gallstone ileus, volvulus, intussusception, abscess, hematoma, foreign body

6. More than half of SBO recurr • True • False • Bathing in tomato juice removes the smell of a skunk • True • False

7. SBO – Quick facts • 20% of acute abdo admissions • Mortality <5% (30% with strangulation, 60% in 1900) • >50% recur

8. H&P • Recurrent abdo pain, crampy, <> • Worry if pain becomes constant severe • Vomiting, distension, constipation • Prev surgery • Vitals: normal, tachy, hypoTN, fever • Distention, ∆BS (↑ pitch), tympany • ±scars/hernia, ±tender mass • Vomiting, distension, constipation • Prev surgery ∆BS Bohner H, et al:  Simple data from history and physical examination help to exclude bowel obstruction and to avoid radiographic studies in patients with acute abdominal pain.   Eur J Surg  1998; 164:777

9. Review of the basics • Types? • Mechanical & functional • Simple & closed loop (±strangulation) • Common causes of ileus? • Trauma, infection, sx, meds, metabolic, renal colic

10. Physicians reliably can distinguish bowel strangulation from simple obstruction • True • False • Cracking knuckles leads to arthritis • True • False

11. Simple vs Strangulated - How good are we? • Confident diagnosis of “non-strangulating obstruction” wrong 31% of the time. • No parameter is sensitive, specific, or predictive for strangulation • Not very good! Sarr et al. Preoperative recognition of intestinal strangulation obstruction: Prospective evaluation of diagnostic capability. Am J Surg 145:176-182, 1983.

12. Pathophysiology • Mechanical SBO → prox dilation → ↑ local peristalsis → ↑ secretory activity → ↓ reabsorption fluid/lytes → capillary/lymphatic obstruction → edema → perforation or strangulation

13. Investigations • Labs: • ↑WBC, ±↑CPK, ±↑lactate • Imaging: • 3 views (60% +SBO, 25% suggestive) • Five places to look for air? • How many A/F levels? • Dilated?

18. CT Scan? • Not required for diagnosis • Can help define site/cause • Other imaging? • Small bowel series, U/S

19. What about U/S?

20. ½ of complete SBO resolve spontaneously • True • False • Eating 3 poppy seed bagels may result in positive urine drug screen for opiates • True • False

21. Management • Fluid resuscitation • Decompression • NG tube • ?Antibiotics • Observation vs. surgery • “never let the sun rise or set on an SBO” • 75% of partial/30-50% complete resolve

22. Take home points • You are not good at dx strangulation • AXR - >2 A/F levels, >2.5cm, air x 5 • ½ of SBO resolve spontaneously

23. Case 2 • 28M central/RLQ crampy abdominal pain, N • Last BM this am, no fever/chills/V • Best guess? • 28F same hx? • 25% signs initially suggestive of appe = gyne • 84F type II DM same hx? • 4M same hx?

24. Case 2 • Vitals – 37.3, 85, 126/85, 18 • RLQ tenderness, +guarding • Investigations?

25. Appendicitis – Quick facts • 7% lifetime incidence • 250 000 cases/yr in the USA • First appendectomy – 1735

26. What the heck is this?

27. The Appendix • "Its major importance would appear to be financial support of the surgical profession." - Alfred Sherwood Romer Leonardo da Vinci (1492)

28. Pathophysiology • Obstruction •  ↑ pressure •  distension •  ischemia + bacteria/PMN invasion •  swells, irritates •  necrosis and rupture

29. History • Three most common symptoms? • abdo pain, anorexia, nausea • Rule out based on pain location? • no, can even have LUQ pain

30. Physical exam • Vitals – 37.3, 85, 126/85, 18 • Do normal vitals r/o appendicitis? • What if T = 38.1? • Low grade fever in 15% (40% if ruptured) • Eponyms • McBurney’s, Rovsing’s, Obturator, Psoas, Dunphy

31. H&P • Three important signs/symptoms? • RLQ pain, rigidity, migration of pain • Four to help rule out appendicitis? • Pain > 48h, similar pain, lack of migration, lack of ↑ pain with movement/cough

32. CMT is uncommon in women with acute appendicitis • True • False • The air expelled in a sneeze can travel up to 100mph • True • False

33. Classic Appendicitis • Peri-umbilical pain  RLQ migration • N, anorexia, V • No history of similar pain in past • Pain < 48hrs at presentation • Pain ↑ with movement/cough • Low grade fever • Rigidity & guarding • Local RLQ tenderness

34. Serial exams • Review of 30 years of publications • “active observation” = reassess pt q2-3h • Pain resolved in 1/3 of patients • No change in perforation rate • Negative appendectomy rate 6% • vs 20-30% (?lower with CT or U/S) Jones PF.  Suspected acute appendicitis: Trends in management over 30 years.  Br J Surg  2001; 88:1570-77.

35. What labs? • Commonly ordered • CBC, β-hcg, U/A • ±LFT’s/lipase, ±CRP • Findings • ↑ WBC, U/A – pyuria, microscopic hematuria • Necessary? • β-hcg!

36. U/S vs CT • CT • SN 94%, SP 95%, LR+ 13.3, LR- 0.09 • + usually visualize appendix, not operator dependent, ID other pathology • - radiation • Contrast? • Rectal – best but not practical • Oral – delay, ?tolerated, esp. helpful in thin/kids • IV – not recommended

37. U/S vs CT • U/S • SN 86%, SP 81%, LR+ 5.8, LR- 0.19 • + pregnant, kids, female, thin pts • - obese, strictures, retrocecal, normal • MRI? • Very sensitive but not available

38. ?Change Management? • 2 studies of CT in pts w/ suspected appendicitis comparing Tx plan before & after access to results of scans • CT changed disposition in 27 – 59% of pts • Prevented d/c of ~3% pts w/ appendicitis • Prevented negative laparotomy in 3-13% • Alternate Dx in 11-20% • Frank et al. Unenhanced helical CT scanning of the abdomen and pelvis changes disposition of patients presenting to the emergency department with possible acute appendicitis. J Emerg Med 2002; 23: 1-7 • Rao et al. Effect of computed tomography of the appendix on treatment of patients and use of hospital resources. N Eng J Med. 1998; 338: 141-6 Thanks Moritz!

39. To image or not? • Imaging based on risk-stratification • Don’t image: • Low risk – minimal physical findings, hungry, alternative dx, hx similar pain, sympt > 3 days • First few hours of pain • Image • Intermediate risk – lack classic appendicitis finding • ?Image • High risk – classic presentation • Will go to OR anyway

40. Wake the surgeon? • Time from onset of symptoms to rupture? • 24-36 hours • Average time to seek medical care • 17 hours • Complication rate • 3% vs 12% with rupture • Mortality • <0.1% vs 3-4% with rupture

41. Take home points • Normal vitals do not rule out appendicitis • Think about U/S over CT in skinny/kids • Image pts with equivocal presentation • Single most important lab test β-hcg

42. Mesenteric adenitis? • Most common associated condition • 5-10% admissions for appendicitis • ?More common than appendicitis • Mostly children • Non-specific infl. of mesenteric LN • Can follow viral illness • Yersinia species (Y. enterocolitica)

43. Mesenteric adenitis? • O/E: • ±Mild fever • Diffuse tenderness, RLQ, no peritonitis • 20% other lymphadenopathy • Ix: • ±↑WBC • U/S or CT may be helpful • Tx: • none, self-limited

44. Case 3 • 65M • Suprapubic and LLQ pain x days, similar bouts of pain in past • Anorexia, nausea • O/E: Vitals normal, LLQ tender, no peritoneal signs, ?distended • #1 in DDx? • Initial investigations?

45. Diverticular disease facts • 10% > 45yrs, 80% > 80yrs • ?Dietary deficiency in fibre • 85% L-sided (opposite in Japan)

46. Definitions

47. Definitions

48. Anatomy/Pathogenesis • Vasa recta penetrate colonic wall • Forms weak points • Small (low fibre) stool  ↑ pressure • herniation of mucosa at vasa recta

50. Diverticulosis