the problem of pain approach to abdominal pain jason phillips, md
TRANSCRIPT
ER approach to abdominal pain
Chief complaint: abd pain Labs: CBC, chem, LFTs, lipase CT abdomen
History Possible PE
How do you approach a workup for abdominal pain?
What are the most likely possibilities?
How do you organize your thoughts?
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
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)
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
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
Localization of visceral pain
Exceptions to the bilateral rule Gallbladder Ascending and descending colon Although bilaterally innervated, they
have predominant ipsilateral innervation
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
Intensity of pain response
Threshold for perceiving pain from visceral stimuli has marked individual variability
Balloon distension experiment in IBS
History
MOST IMPORTANT CLUE to the source of abdominal pain
Type of pain Visceral = dull, aching, poorly localized Parietal = sharp, well localized Referred pain
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)
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
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)
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
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
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
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
Is it functional or not?
Clues that are suggestive of functional Absence of nocturnal symptoms
Exacerbated by stress
Distractible exam
“Gut feeling”
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
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:1. Relieved with defecation2. Change in frequency of stool3. Change in appearance of stool
Irritable Bowel Syndrome
3 types of IBS patients Constipation-predominant
Diarrhea-predominant
Alternating
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
Irritable Bowel Syndrome
Pathophysiology
Alterations in motility
Visceral hyperalgesia
Postinfectious IBS – lymphocytic infiltration of myenteric plexus?
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
Upper abdominal pain:Biliary disease
1. Most common location – epigastric NOT RUQ
2. Steady onset; last hours (not minutes or seconds)
3. Can radiate to right scapula
Biliary colic Cholecystitis Acute cholangitis
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?
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)
Upper abdominal pain:Dyspepsia
Dyspepsia = “persistent or recurrent abdominal pain or discomfort in the upper abdomen.”
Vague diagnosis that includes a long DDX
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
Upper abdominal pain:Dyspepsia
GERD = heartburn (retrosternal burning), water brash (acid taste in mouth), regurgitation, and sensation of dysphagia
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)
Gastroparesis
Often overlooked as a cause for epigastric pain
Gastroparesis symptoms Nausea 93% Abdominal pain 90%
Epigastric burning, vague, cramping Early satiety 86% Vomiting 68%
Gastroparesis
60% report pain is worse after eating 80% reports pain interrupted sleep Vomiting food hours later
Look for important historical clues Diabetes Meds (narcotics, anticholinergics) Recent viral gastroenteritis CNS disease Amyloid, scleroderma
Upper abdominal pain:Pancreatitis
Acute Pancreatitis = acute epigastric pain that radiates to back, constant, severe, rapid onset within 1 hour, lasts days, associated nausea/vomiting, relieved with sitting forward; assoc restlessness
Rarely diffuse pain, RUQ, or LUQ
Upper abdominal pain:Pancreatitis
Diagnosis is made when you have at least 2 of the 3 criteria:
- Typical pancreatitic pain
- Elevation in amylase and lipase
- Abnormal imaging
Upper abdominal pain:Pancreatitis
Chronic pancreatitis = similar pain, less severe and onset 20-30 minutes after a meal, can be episodic (early in disease course) or constant (late finding)
Associated malabsorption (pancreatic exocrine insufficiency) and diabetes (endocrine insufficiency) Steatorrhea does not occur until 90% or
more of pancreatic function is lost
Lower abdominal pain
Appendicitis = begins as periumbilical pain that localizes to RLQ (McBurney’s point) Initially visceral pain (superior mesenteric ganglion) RLQ when inflammation extends to peritoneal
surface (parietal pain)
Pain evolves over hours
Exam: peritoneal irritation (rebound) + fever Labs: Elevated WBC
Lower abdominal pain
Diverticulitis = usually LLQ abdominal pain Constant w insidious onset Worsening over days Associated symptoms of fever and
worsening constipation
Lower abdominal pain
Exam: spectrum of severity Mild LLQ tenderness Severe LLQ rebound
Labs: Elevated WBC Imaging
Lower abdominal pain
70% of diverticulitis in Western countries in left sided. What group of patients usually have right sided diverticultitis (~75%)?
Do seeds cause diverticulitis and should they be avoided?
Lower abdominal pain
IBD can give lower abdominal pain with diarrhea, weight loss, hematochezia, fever These clues are more obvious
However, 10% of patients with Crohn’s disease will NOT have diarrhea and can present with abdominal pain RLQ ileocecal CT, colonoscopy, SBFT
Lower abdominal pain
Hernia = weakness or disruption of the abdominal wall Indirect: at the internal ring Direct: Hesselbach’s triangle Umbilical Epigastric Incisional
Lower abdominal pain
Groin hernias pain or dull pressure with lifting, straining, or increasing intrabdominal pressure; worse with prolonged standing and at end of day Physical exam is crucial
Outright pain at rest is concerning for strangulation
Lower abdominal pain
If in doubt, consult surgery for an opinion
If a hernia is bright red and impossible to reduce, call a surgeon immediately
Lower abdominal pain: Non-GI causes
Nephrolithiasis Colicky pain (spasms lasting 20-60 mins) Site depends on location of stone
(flankgroin) UA: hematuria (neg in 20-30% of cases) CT renal stone protocol
Lower abdominal pain: Non-GI causes
Pelvic inflammatory disease Pelvic pain during menses or coitus Onset during of shortly after menses Bilateral Usually less than 2 weeks
Exam critical: speculum and bimanual exam
Diffuse abdominal pain
Viral gastroenteritis = colicky abdominal cramps, watery diarrhea, and nausea/vomiting Incubation 24-48 hours Symptoms begin with abdominal cramps
and/or nauseamost have vomiting and watery diarrhea
Mild fever, myalgias Lasts 48-72 hrs
Diffuse abdominal pain
Obstruction Periumbilical pain with paroxysms of
cramps occurring every 4-5 minutes Abdominal distension Nausea Obstipation may be delayed up to 24 hours
History of abdominal surgery or malignancy
Diffuse abdominal pain
Obstruction Exam: distended appearance, tympanic,
high pitched tinkle or large bowel sounds NGT decompression
Abdominal x-rays – supine and upright
Ischemia
Acute mesenteric ischemia Embolism Thrombosis Vasospasm
Chronic mesenteric ischemia Intestinal angina
Can be difficult to diagnose
Acute mesenteric ischemia
Embolic sudden onset of severe, diffuse pain Writhing in pain Abdominal exam feels benign - :pain out of
proportion to exam” Be suspicious in the right patient: atrial
fibrillation, mechanical heart valves, age
Acute mesenteric ischemia
Thrombotic and non-occlusive insidious onset of pain
Labs: nonspecific until late in the course
Imaging: mesenteric angiogram