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

The Problem of Pain

Approach to Abdominal Pain

Jason Phillips, MD

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

Two basic problems with abdominal pain

Localization of visceral pain

Intensity of pain response


Visceral pain localizes to midline Bilateral, symmetric innervation Afferent fibers celiac, superior

mesenteric, or inferior mesenteric ganglion Localizes: epigastrium, periumbilical, and

lower abdomen


Exceptions to the bilateral rule Gallbladder Ascending and descending colon Although bilaterally innervated, they

have predominant ipsilateral innervation


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)

History

Associated symptoms Nausea/vomiting Weight loss Changes in bowel habits

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

Further evaluation

Directed at pain syndromes

Labs Imaging

Is the pain functional or not?

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”

Pain syndromes

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


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


3 types of IBS patients Constipation-predominant

Diarrhea-predominant

Alternating


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


Pathophysiology

Alterations in motility

Visceral hyperalgesia

Postinfectious IBS – lymphocytic infiltration of myenteric plexus?


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 Dyspepsia Pancreatitis Gastroparesis Other

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


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


GERD = heartburn (retrosternal burning), water brash (acid taste in mouth), regurgitation, and sensation of dysphagia


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)


Best test? 3 strategies

Empiric PPI H pylori – test and treat EGD

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

Gastroparesis

Workup EGD or UGI – rule out GOO

Gastric emptying scan

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


Diagnosis is made when you have at least 2 of the 3 criteria:

- Typical pancreatitic pain

- Elevation in amylase and lipase

- Abnormal imaging


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

Upper abdominal pain:Other causes

Acute MI Pneumonia Splenic abscess or infarct

Lower abdominal pain

Appendicitis Diverticular disease IBS Crohn’s disease Hernia Other


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


Diverticulitis = usually LLQ abdominal pain Constant w insidious onset Worsening over days Associated symptoms of fever and

worsening constipation


Exam: spectrum of severity Mild LLQ tenderness Severe LLQ rebound

Labs: Elevated WBC Imaging


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?


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


Hernia = weakness or disruption of the abdominal wall Indirect: at the internal ring Direct: Hesselbach’s triangle Umbilical Epigastric Incisional


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


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

Gastroenteritis IBS Obstruction Mesenteric ischemia


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


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


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

Questions?

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

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