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An Approach to Abdominal Pain

Dan Mielnicki, MD

Assistant Professor

Medical College of Wisconsin

Dept of Emergency Medicine

Objectives

• Overview of abdominal pain

• Approach to abd pain patientsHistory and Exam– History and Exam

– Lab Tests– Radiography

• Abd pain in elderly, children, and pregnancy

• High-risk presentations

Ground Rules Rule #1

• Never trust the abdomen– Examine, then re-examine, then re, re-examine

Rule #2

• You will miss an important abdominalimportant abdominal pain diagnosis at least once in your career

Rule #3

• Over-reliance on lab tests and imaging studies to rule in or rule out a disease process is a bad idea– Often lead us astray

• WBC count is insensitive and non-specificp

– Consume healthcare resources• “Screening labs”• CT scans and other complex imaging

– Expose the patient (& yourself) to harm• Radiation, needle-sticks injuries, etc

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Rule #4

• Sometimes the best test is observation

Rule #5

• Vital signs are vital!– Ignore them at your (and the patient’s) peril

• Especially, tachycardiap y, y

• But, especially hypotension!

Rule #6

• Classic presentations (of any disease) are generally the exception, not the rule

Rule #7

• The answer to abdominal pain is not always in the abdomen

Rule #8

• Pain located outside the abdomen can be from an abdominal source

Rule #9

• Even crazy people get sick

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Rule #10

• The very old & the very young don’t follow any rules– Same for the very drunk and immunosuppressed

The Basics

• Visceral pain– Embryonic origin

• Foregut, midgut, hindgut

– Autonomic nerves invested in visceraAutonomic nerves invested in viscera– Stretching solid/hollow organ capsules– Localize midline

• Somatic pain– From parietal afferents– Dermatomal distribution– More localized, sharp, deep

Pain that radiates to…

• Back =

• Flank =

Pancreatitis

Renal colic

• Tip of the scapula =

• L shoulder =– Eponym?

Biliary colic

Spleen (blood), free air

Kehr’s sign

Abdominal Topography

Biliary colicHepatitisPeptic ulcer diseasePancreatitisPerforated viscus

Small bowel obstructionMesenteric IschemiaPancreatitis

Adam.com

AppendicitisRegional enteritisRenal colicPIDOvarian cyst/torsionEctopic pregnancyTesticular torsion

DiverticulitisRenal colicPIDOvarian cyst/torsionEcoptic pregnancyTesticular torsion

Pain History 101

• Onset

• Location

• Duration

• Character

• Alleviating/Aggravating Factors

• Associated Symptoms

• Radiation

Pain History 101

• Onset

• Location

• Duration

• Character

• Alleviating/Aggravating Factors

• Associated Symptoms

• Radiation

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Pain clues…

• Steadily worsening and localizing pain &/or pain that worsens with bumps in the road– Think peritonitis

• Appendicitis cholecystitis diverticulitis ruptured ectopicAppendicitis, cholecystitis, diverticulitis, ruptured ectopic

• Abrupt onset severe pain– Think perforation, dissection, torsion, mesenteric ischemia

• Patient writhing, crescendo/decrescendo pain– Think colic: biliary, renal, intestinal obstruction

• Symptoms above and/or below abdomen– Think aorta and referred pain

The interrogation

• Open-ended questions are critical!– Let the patient talk…do not lead the

witness– Do better than 8 seconds

• Helpful visitors stayHelpful visitors stay• Bounce unhelpful visitors

– Children– “Fiancés”– “my boy(s)” or “my girl(s)”– Potentially abusive partners– Parents of teens and pre-teens– Bosses &/or co-workers– Enablers

The interrogation

• Some other important questions:– “Has this ever happened before?”– “What is your biggest concern?”– “When you say (fill in the blank) what do you mean?”y y ( ) y– “Is there anything else you think is important that I

haven’t asked?”

• If the pain is chronic…– What was it about TODAY that made you decide to

come in?– What do you think needs to get done?

Laying of hands

• Expose the abdomen– Scar + distention (- farting) = obstruction

Di i f l ( i d)– Distention + young female (- period) = pregnancy

– Hernias

– Bruising, lesions, redness

Laying of hands

• Auscultation: the least useful– Quiet abdomen: peritonitis or ileus

Cope’s Early Diagnosis of the Acute Abd 21st edition 2005

Laying of hands

• Palpation– Warm hands or wear gloves– Gently, systematically move from least to most painful

areaarea– Save provocative or more painful tests for last

• Murphy’s sign• Appendicits tests

– Rovsing’s, Psoas, Obturator, etc.

• Palpation of liver or spleen• DRE

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Laying of hands

• Percussion– The best way of eliciting rebound tenderness

– Tympanitic = ileus, obstruction

Cope’s Early Diagnosis of the Acute Abd 21st edition 2005

Useful bits of information

• In appendicits…– The rectal exam is not useful– Having patient jump up and down is better than shaking

the bed or pelvis– If equivocal signs/symptoms, re-examination in 12 hours

is usually safe

• Abd pain + vomiting ≠gastroenteritis– Stuff needs to be coming out of both ends– Better if some others are also symptomatic– GE is a diagnosis of exclusion

• The most common misdiagnosis in patients with appendicitis

West J Med 173: 207 Sept 2000Minerva Chir 63(1): 9-15 Feb 2008

Useful bits of information

• Always look below the belt in young men or women with abdominal pain– Testicular torsion,

incarcerated hernias

– PID, ovarian cysts/torsion, TOA, ectopic pregnancy

Useful bits of information

• Carnett’s sign– Focal tenderness with flexion of abd wall

musculature

– Signifies potential abd wall source

– May not be useful for acute presentations

Am Fam Physician. 2008

Useful bits of information

• Cognitive errors to avoid– Anchoring bias

• Sticking with initial diagnosis based on early information despite other data that indicates alternate diagnosisg

• Premature closure: failure to consider alternate diagnoses after your diagnosis is reached

– Confirmation bias• Favoring information to fit a preconceived

diagnosis, over other information that may be pointing elsewhere

Bottom Line: Before discharging a patient ask yourself,“Have I considered all possible diagnoses?”

Testing, testing

• Laboratory testing– White blood cell count

• Poorly sensitive and non-specific for appendicitis

• Repeat after me: “There is no lab test for appendicitis”

– Liver function tests• Albumin, INR: truly tests its function

• Transaminases (AST/ALT): liver parenchyma

• Bilirubin, GGT: Biliary obstruction, alcohol

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Testing, testing

• Urinalysis– Urine hcg in women

– Importance of sterile pyuria

– Cath specimen preferred in elderly, menstruating, or if highly contaminated

• Lipase– Superior to amylase for pancreatitis

• Cultures– Suspect intra-abd sepsis or pyelo

Testing, testing

• Imaging:– Flat plate (aka KUB): little

usefulness• Suspected fb, tube confirmation,

uroliths?, appendoliths?

– Abdominal Series: suspected obstruction or free air

• Sentinel loop• Constipation is NOT a

radiographic diagnosis!

Testing, testing

• Ultrasound– Up and coming imaging modality

• Biliary• Aorta• Appendicitis

– Pregnancy– Children

• Renal• Pelvic structures

– Early pregnancy– PID/TOA– Ovaries

Testing, testing

• CT scan– Highly sensitive (& highly over-used) BUT NOT

PERFECT• Ionizing radiation and cancer risk getting lots of headlines• 1 Abd scan = 200 300 CXRs or 2 yrs of background radiation• 1 Abd scan = 200-300 CXRs, or 2 yrs of background radiation

– Non-contrast• Urolithiasis or “stone protocol”• Probably sufficient in obese patients with appendicitis,

diverticulitis, etc.

– IV contrast• Most infectious, inflammatory, and vascular disorders

– Angio• Mesenteric ischemia, AAA leaks, aortic dissection

Special Populations

• Elderly

• Pediatrics

• Pregnancy

Abd Pain in Elderly

• Fun facts!– 20% ED abd pain presentations require surgery

– Perforation rate appendicitis = 50%• 5x higher than young adults

– Rate of initial misdiagnosis = 40%• Lack of “classic” presentations, exam findings, expected lab

abnormalities, etc.

– Mortality 6-8x higher than in younger pts• > 80 yo mortality rate is 70x higher

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Differential Diagnoses

• Biliary tract disease

• Bowel obstruction– SBO, LBO, and volvulus

• Diverticulitis

• UTI– Irritative voiding symptoms

often absent

• GastroenteritisBe very careful

• Gastritis/PUD– 1/3 pts PUD present with

melena & no pain

• Appendicitis– 10% cases occur in elderly

– Half of all deaths

• Bladder obstruction

– Be very careful– Often not GE, & if it is can

cause significant M & M

• Malignancy– 10% undifferentiated abd pain

• Vascular processes– AAA– Aortic dissection– Mesenteric ischemia

Challenges in the Elderly

• Delayed presentations common– Fear losing independence and financial hardships– Transportation, mobility, and communication issues

Obt i i Hi t• Obtaining History– Underlying dementia, delirium– Stoicism--don’t want to bother anyone…– Impaired hearing, cerebrovascular disease, mental

status changes, etoh abuse– Family, friends, care takers, EMS providers can be

invaluable

Challenges in the Elderly

• “Atypical” features– Fever is uncommon with peritonitis

• Hypothermia

Medications as confounders– Medications as confounders• Beta blockers• Corticosteroids

– Block inflammatory reactions and attenuate peritoneal findings

– Render elevated wbc count totally useless– PUD and perforated viscous more common

Challenges in the Elderly

• Physical Exam:– Vital signs deceptively “normal”

• Beware relative hypotension

– Importance of ECGImportance of ECG• Ischemia, infarction upper abd pain• A-fib and mesenteric ischemia

– Peritoneal signs are important but NOT predictive of specific disease or need for surgery

• Tenderness often attenuated

– DRE has limited utility• Occult blood testing, stool impactions, prostate

Challenges in the Elderly

• CBC:– Cautious with wbc count

• Pay attention if very high

• Urinalysis– Pyuria is common but NOT

Rule of thumb: # labs ordered proportional to decades of life lived and degree of disorientation

• Pay attention if very high, very low, or bandemia

• BMP:– Glucose– Anion gap– Renal function

• Lipase– If elevated think gallbladder

• LFTs

always UTI

• Lactate– Marker for severe disease

• Cultures

• Coags/ Blood type– If vascular etiology, GI bleed, or

anticipate surgery

Elderly Take Home Points

• Extra cautious in approach– 1 in 5 have surgical cause for pain– 40% initially misdiagnosed

Much higher morbidity and mortality– Much higher morbidity and mortality

• Don’t expect “classic” signs or symptoms• If cause can’t be identified

– Admit or Observe– Very close follow up

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Pediatric Abdominal Pain

• Many of same limitations exist as in elderly– Historical limitations centered on FEAR!

• Adolescents probably more embarrassment

– Exam is often challenging• Close observation during the interview• Bonding with child &/or parents• Get all infants naked

– Hair tourniquets, incarcerated hernias, abscesses, testicular torsion, signs of abuse

• Look closely for extra-abdominal causes– Strep pharyngitis– Pneumonia– DKA!

Specific Pediatric Diagnoses

• Newborns and Infants• Colic

– Etiology?• Increased intestinal gas

N h• Neuro or psych• Normal?

– Starts 2 wks, peaks at 4-8 wks, resolves by 12 weeks– Rule of 3’s:

• 3 hrs/day, 3 days/wk, 3hr duration

– Keys:• Child appears well between episodes• No associated vomiting/diarrhea, fevers, or weight loss

– Treatment: Earplugs & Time

Specific Pediatric Diagnoses

• Newborns and infants– Malrotation with midgut volvulus

• 60% occur within 1st 30 days life– 90% within the first year90% within the first year

• Key historical feature:– Bilious vomiting

• Diagnostic modality of choice:– UGI

• Take home point: if considering this diagnosis, 1st call is to a pediatric surgeon Children’s Hosp Wis

Specific Pediatric Diagnoses

• Infants - Toddlers– Intussusception

• Classic Triad: – Found in only 20% of cases!

Hi h i d f i i– High index of suspicion

– Key is observation

• Colicky pain that waxes and wanes

• Bloody stool is late and ominous finding

• Undifferentiated AMS, lethargy/unresponsiveness, think intussusception!

– Diagnosis = Therapy:

Appendicitis in Children

• The most common cause of surgical-related abd pain– Rates are highest in pre-teens and teenagers

• Perforation is more common in children– Almost universal in toddlers – Not due to late presentations rather “atypical” presentationNot due to late presentations, rather atypical presentation

• Lab studies suffer from same limitations• Imaging choices

– Plain films: appendicoliths present in 10%– Ultrasound: Great if positive, but rarely diagnostic– CT scan: High sensitivity but ionizing radiation concerns

• Key to diagnosis: high index suspicion, early surgical referral, observation

Other Diagnoses

• Constipation– Very common– Infants require more thorough

evaluationOld kid di t d

• Incarcerated hernias– Inguinal >> Umbilical

– Older kids dietary and psychosocial issues predominate

• Gastroenteritis– Again, be cautious– Vomiting AND diarrhea

• Vomiting before diarrhea

– Much more confident if others similarly affected

• Meckel’s diverticulum– Rectal bleeding >> pain

– Intusussception, sbo, perforations

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The most important question in vomiting infant?

Bilious

Non-bilious

Pregnancy

• Pregnancy-related changes– Uterus becomes abdominal organ @ 12 wks

• Can make pain localization more difficult• May mask peritoneal findings initiallyy s pe o e d gs y

– Gastric, biliary, and colonic emptying slows• Increase n/v, biliary colic, and constipation

– LES pressure decreases• GERD

– Ureters dilate and peristalsis slows• Urine stasis --> infections & urolithiasis

1st Trimester Problems

• Ectopic Pregnancy– Classic presentation:

• Positive predictive value of 14%

All l i h bd i l i i– All early pregnancy with abdominal pain are ectopic until proven otherwise

• Beta-hcg testing + Ultrasound

• Equivocal testing should have prompt follow up

– Risk Factors: prior tubal pregnancy or surgery, h/o PID, cigarette smoking, fertility treatments, IUD

1st Trimester Abd Pain

• Spontaneous miscarriage– Difficult to differentiate by history and exam

• Ovarian torsion– Large ovarian cyst(s)

• Rupture CL cyst • PID and TOA

– Rarely encountered in pregnancy

Appendicitis in Pregnancy

• (T/F): The right lower quadrant is the most common location of pain in pregnant patients with acute appendicitisp pp

TrueAm J Obstet Gynecol 2000; 182(5); 1027-29Am J Roentgenol 2006; 186(3) 883-887Int Jj Gynaecol Obstet 2003; 81(3): 245-47

Appendicitis in Pregnancy

• Historical and examination findings mirror that of non-pregnant pt– Peritoneal findings are not part

f l

• Imaging choices– Ultrasound: operator dependent

– MRI: data not in yet; radiologist find difficult to read

of normal pregnancy

• Leukocytosis is completely unhelpful– Unless bandemia present

• Delay in diagnosis– Ruptured appy ass’d with 20-

25% fetal mortality rate and 4% maternal mortality

– CT scan:• Ionizing radiation concerns re:

teratogenicity and mentalretardation

• Laparoscopy– Standard at some institutions

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3rd Trimester Abd Pain

• Labor– Pretty obvious

• Pre-eclampsiap• Placenta abruption

– Risk Factors: Pre-eclampisa, trauma, smoking?– Diagnosis:– High fetal and maternal morbidity and mortality

• Placenta accreta

So…

“High risk” presentations

• Those more likely to require surgery or other immediate intervention– Pain that is acute in nature (< 48 hours)– Pain before vomiting– Elderly– Pregnancy– History of

• Abdominal surgery• Serious intra-abd pathology• Immunodeficiency• Alcoholism• Cardiovascular disease

“High risk” Diagnoses

• Medico-legal thin ice– Appendicitis

• Missed cases are the most common cause for malpractice suits in pts with abdominal pain

Ectopic pregnancy– Ectopic pregnancy• Must consider this in every woman presenting

with abdominal pain• Negative urine (or serum) hcg essentially rules

out this dx

– AAA• > 90% mortality if ruptured• Classic presentation is rare• Most frequently misdiagnosed as…

Case

• 78 yo female patient with metastatic breast CA on chemoRx, 1 week of constipation now 24 hours abd pain & vomiting that p gbegan abruptly

• 109/68 86 32 99.6 SpO2 98% on RA

Case

• Important Clues– Elderly

– ImmunocompromisedImmunocompromised

– Tachypnea

– “Relative” hypotension

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Case

• Awake, confused, ill-appearing

• Abd tender diffusely worse in the LLQ with• Abd tender diffusely worse in the LLQ with some guarding

• No advanced directives, chemoRx is palliative, family wants everything done.

Work up?Work up?

Case

• AAS: No free air, no obstruction, moderate stool in the colon

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2.3

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N 26 Ba 15 L 53

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3.1

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LFTs/lipase: Normal

CT scan

Questions?

Challenge

• Your medical education hasn’t ended

• Set goals for your residencyg y y

• Become a subject matter expert in your field

• Root out dogma– Replace it with sound evidence-informed practice

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Thank you!