The Problem of Pain

1. The Problem of Pain Approach to Abdominal Pain Jason Phillips, MD

5. ER approach to abdominal pain Chief complaint: abd pain • Labs: CBC, chem, LFTs, lipase • CT abdomen • History • Possible PE

6. How do you approach a workup for abdominal pain? What are the most likely possibilities? How do you organize your thoughts?

7. The Problem of Pain • Neurologic basis of pain • Why is it difficult to localize? • Why does the intensity of the pain vary? • General overview of approaching a patient with abdominal pain • Pain syndromes

8. Neurologic basis of abdominal pain • Pain receptors respond to • Mechanical stimuli • Chemical stimuli • Nociception mechanical receptors are located on serosa, within the mesentery, in the GI tract wall in the • myenteric plexus (Auerbach plexus) • submucosal plexus (Meissner plexus)

9. Neurologic basis of abdominal pain • Mucosal receptors respond to chemical stimuli • Substance P, serotonin, histamine, and prostaglandins • Chemical stimuli are released in response to inflammation or ischemia

10. Two basic problems with abdominal pain • Localization of visceral pain • Intensity of pain response

11. Localization of visceral pain • Visceral pain localizes to midline • Bilateral, symmetric innervation • Afferent fibers  celiac, superior mesenteric, or inferior mesenteric ganglion • Localizes: epigastrium, periumbilical, and lower abdomen

13. Localization of visceral pain • Exceptions to the bilateral rule • Gallbladder • Ascending and descending colon • Although bilaterally innervated, they have predominant ipsilateral innervation

14. Localization of visceral pain • Referred pain • Somatic fiber “cross-talk” • Activate same spinothalamic pathways  referred pain as the cutaneous dermatome sharing the same spinal cord level (Gallbladder – scapula) • Results in aching pain with skin hyperalgesia and rigidity

16. Intensity of pain response • Threshold for perceiving pain from visceral stimuli has marked individual variability • Balloon distension experiment in IBS

18. History • MOST IMPORTANT CLUE to the source of abdominal pain • Type of pain • Visceral = dull, aching, poorly localized • Parietal = sharp, well localized • Referred pain

19. History • General location • Generalized, RUQ, epigastric, LUQ, periumbilical, RLQ, LLQ, and ‘migratory’ • General region localizes organs/structures to include in the DDX • Radiation of pain (e.g., acute pancreatitis)

20. History • Onset of pain • Most gradual, steady crescendo (e.g., cholecystitis) • Abrupt, “10/10” – suggestive of perforation • Quality of pain • Colicky (comes and goes) – e.g., gastroenteritis • Steady – (e.g., acute pancreatitis; biliary colic is a misnomer) • Burning

21. History • Severity of pain • Generally corresponds to severity of illness • However, marked patient variability (“12/10 pain” is often functional or has functional overlay) • Aggravating or Relieving factors • Eating (mesenteric ischemia vs PUD) • Position changes (acute pancreatitis, peritonitis)

22. History • Associated symptoms • Nausea/vomiting • Weight loss • Changes in bowel habits

23. Physical exam:Acute abdomen or not? • General appearance and Vital signs • Abdominal exam • Auscultation • Bowel sounds present? • High pitched sounds of obstruction • Stethoscope palpation • Percussion • Tympany = distended bowel • Most humane test for rebound tenderness

24. Physical exam:Acute abdomen or not? • Palpation: • Acute abdomen or not? Peritoneal signs • Rebound tenderness • Mass? Hernia • Abdominal wall maneuvers • Leg lift maneuvers (Carnett’s sign) • Abdominal crunch

25. Further evaluation • Directed at pain syndromes • Labs • Imaging

26. Is the pain functional or not?

27. Functional abdominal pain • Can be difficult to distinguish from organic pain • Can only be labeled as functional when organic causes are excluded • Can superimpose on organic pain • Should not cause • Weight loss, Anemia, GI bleeding, Fever, Night sweats

28. Is it functional or not? • Clues that are suggestive of functional • Atypical history • RUQ that lasts 20 sec is not biliary colic • Dyspesia that worsens with a PPI • Overly dramatic descriptions of pain • “It feels like a knife stabbing me over and over and then something is pushing inside out” • Hyperbolic intensity • “11/10 epigastric pain” with a benign abd exam

29. Is it functional or not? • Clues that are suggestive of functional • Absence of nocturnal symptoms • Exacerbated by stress • Distractible exam • “Gut feeling”

31. Pain syndromes

32. Irritable Bowel Syndrome • Prevalence: 10-15% of overall population • Only ~15% of patients seek medical care • 25-50% of gastroenterology visits • Annual healthcare cost: $1.7 billion

33. Irritable Bowel Syndrome ROME criteria: • 12 weeks or more of abdominal pain/discomfort in the last 12 months (does not have to be consecutive) • Two or more features: • Relieved with defecation • Change in frequency of stool • Change in appearance of stool

34. Irritable Bowel Syndrome 3 types of IBS patients • Constipation-predominant • Diarrhea-predominant • Alternating

35. Irritable Bowel Syndrome What is the normal range for frequency of bowel movements? Rule of 3s: - Normal = Anywhere from 3x per week to up to 3x per day

36. Irritable Bowel Syndrome Pathophysiology Alterations in motility Visceral hyperalgesia Postinfectious IBS – lymphocytic infiltration of myenteric plexus?

37. Irritable Bowel Syndrome How do you prove its only IBS? Rome criteria positive for IBS  • No alarm features and mild symptoms, reassurance and treatment of symptoms • Alarm features or severe symptoms, consider referral to GI

38. Upper abdominal pain • Biliary disease • Dyspepsia • Pancreatitis • Gastroparesis • Other

39. Upper abdominal pain:Biliary disease • Most common location – epigastric NOT RUQ • Steady onset; last hours (not minutes or seconds) • Can radiate to right scapula • Biliary colic • Cholecystitis • Acute cholangitis

41. Upper abdominal pain:Biliary disease • Workup: • Labs: When are liver tests abnormal? • Imaging: What is the most sensitive imaging study for biliary tract disease? • What are its limitations?

42. Upper abdominal pain:Biliary disease • Labs: LFTs increase with choledocholithiasis (first transaminases, then AP/T Bili) • Ultrasound: Sensitivity Specificity • Cholecystitis 88% 89% • HIDA 97% 90% • Gallstones 84% 99% • Biliary dilation 55-91% • Choledocholithiasis 50 vs 75% (nondilated vs dilated CBD)

43. Upper abdominal pain:Dyspepsia • Dyspepsia = “persistent or recurrent abdominal pain or discomfort in the upper abdomen.” • Vague diagnosis that includes a long DDX

45. Upper abdominal pain:Dyspepsia • 80-100% of ‘dyspepsia’ is a acid-related phenomenon or functional • Usually an outpatient problem • Peptic ulcer pain = epigastric, burning or hunger-like, worse between meals, relieved with food, nocturnal pain, associated nausea

47. Upper abdominal pain:Dyspepsia • GERD = heartburn (retrosternal burning), water brash (acid taste in mouth), regurgitation, and sensation of dysphagia

48. Upper abdominal pain:Dyspepsia • Functional dyspepsia = same symptoms but no organic etiology can be found • 12 weeks over last 12 months • Not relieved with BM or associated with alterations in BMs (i.e., NOT IBS)

49. Upper abdominal pain:Dyspepsia • Best test? • 3 strategies • Empiric PPI • H pylori – test and treat • EGD