Abdominal pain

CRACKCast E027 – Abdominal Pain

In CRACKCast, Podcast by Adam Thomas1 Comment

This episode of CRACKCast cover’s Rosen’s Chapter 27, Abdominal Pain. Abdominal pain is one of the most common presenting symptoms in the ER and a good approach is vital for ER docs.

Shownotes – PDF Link 

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Rosen’s in Perspective

  • Common and challenging presentation:
    • History and physical examination can be misleading
    • Serious pain can be benign and mild pain can be serious

Epidemiology

  • Groups that require special consideration in the work up:
    • Elderly
      • Commonly missed diagnoses
        • Diverticulitis
        • Ruptured AAA
        • Mesenteric ischemia
      • Immunocompromised (uncontrolled DM, HIV, liver disease, chemo)
        • Presentation can be misleading due to lack of an inflammatory response
      • Women of reproductive age
        • Pelvic organs can lead to more missed pathologies
        • Ectopic pregnancy

Pathophysiology

  • Pain is derived from three pathways:
    1. Visceral
    2. Somatic
    3. Referred
  • Visceral pain:
    • Stimulation from autonomic nerves in the visceral peritoneum surrounding organs
      • A result of gas, fluid, stretching, edema, blood, cysts, abscesses
      • If the affected organ undergoes peristalsis, then the pain is usually intermittent, crampy and/or colicky in nature
    • Pain follows the embryonic somatic segments:
      • Upper, periumbilical, lower abdominal pain
        • Foregut = upper pain = from stomach, duodenum, liver, pancreas
        • Midgut = periumbilical pain = small bowel, proximal colon, appendix
        • Hindgut = lower abdominal pain = distal colon, genitourinary tract
      • Localization of pain only occurs when the parietal peritoneum becomes affected by the inflammatory process
  • Somatic pain:
    • Occurs with irritation of parietal peritoneum, thereby allowing the patient to localize exactly the location of the pain.
  • Referred pain:
    • “Pain felt at a distance from its originating source”
    • This is due to peripheral afferent nerve fibers entering varying spinal cord levels

[1] List and explain 8 causes of life-threatening abdominal pain

  1. Ruptured ectopic pregnancy
    • Females of childbearing age. 1/100 pregnancies
    • Risk factors:
      1. Non-white race, older age, history of STI/PID, infertility treatment, IUD in the last year, tubal ligation, previous ectopic pregnancy, smoking, fallopian surgery
    • Symptoms: Severe, sharp pain or may be diffuse with shock or peritonitis
      1. With or without vaginal bleeding.
    • Physical exam features do not rule in or out the diagnosis
      1. Abdominal and vaginal symptoms may or may not be present.
    • FAST exam, U/S, BHcG necessary
  1. Ruptured or leaking abdominal aneurysm
    • Increases with advanced age, men, or HTN, DM, smoking, COPD, CAD, connective tissue disease, trauma
    • Symptoms: usually asymptomatic until rupture
      1. ACUTE onset epigastric, back pain WITH syncope and shock. May radiate to back, groin, testes.
      2. May have normal vital signs with normal exam and normal femoral pulses.
    • Abdominal plain films – abnormal in 80% of cases; can do FAST
      • CT abdomen is test of choice.
  1. Mesenteric ischemia
    • Peak: elders, CV disease, CHF, arrhythmias, sepsis, dehydration
      • 70% mortality
    • Mesenteric venous thrombosis – associated with hypercoagulable states
      • Haematological, inflammation, trauma
    • Types of lesions:
      • Arterial occlusion – sudden / emboli / low flow atherosclerosis
    • Symptoms: periumbilical then diffuse pain, with nausea and vomiting, at times postprandial.
    • May have a normal exam
    • Labs: Metabolic acidosis with lactic acidemia. NEED CT to diagnosis.
  1. Intestinal obstruction
    • Peaks in infants and the elderly or post-operative
    • Etiology:
      1. Adhesions, cancer, hernias, volvulus, infarctions,
      2. Usually have normal vitals until bowel strangulation or dehydration occurs
  1. Perforated viscus
    • Incidence increases with advancing age (risks: diverticular dz & PUD)
      1. Duodenal ulcer erodes through stomach
      2. Colonic diverticula
        • Gallbladder and large bowel perforations are rare
      3. Symptoms: acute onset epigastric pain, vomiting, then developing into a fever
      4. Diffuse board-like abdomen with guarding, tachycardia, fever
      5. Upright radiograph shows air under diaphragm in 70-80% of cases
  1. Acute pancreatitis
    • Peaks in adulthood – alcoholism, biliary tract disease or manipulation
      1. Hyperlipidemia, hypercalcemia, ERCP, cancer, ischemia, trauma, ARDS, spontaneous hemorrhage into the pancreas
    • Sx: acute onset epigastric pain, more than findings on exam
    • Rarely have rebounding or guarding because the organ is retroperitoneal
    • Grey turner’s or cullen’s sign may be present if it is hemorrhagic
    • Workup:
      1. Lipase, U/S+/- CT scan can show necrosis or abscess
  1. Ascending cholangitis
    • Charcot’s Triad
      • Fever
      • RUQ
      • Jaundice
        Antibiotics on board ASAP
  1. Complicated diverticulitis or appendicitis (ruptured or with abcesses)
    • IV fluid resuscitation + IV Antibiotics; Surgery

[2] List 15 causes of extra-abdominopelvic abdominal pain

  • Must consider extra-abdominal causes of pain – See box 27-1
    Box 27-1 - Important extra-abdominopelvic causes of Abdominal Pain. From Rosen's.

    Box 27-1 – Important extra-abdominopelvic causes of Abdominal Pain. From Rosen’s.

  • Key is to visualize what’s “around” the black box of the peritoneal cavity!
  1. Thoracic
    • MI / angina
    • Pneumonia / PE
    • Perimyocarditis
  2. GU
    • Torsion of the testicles
    • Penile pathology
    • Intra-vaginal foreign body / mass / pathology
  3. Superficial
    • Muscle hematoma or herpes zoster
  4. Systemic
    • Infectious
      1. Pharyngitis (in kids)
      2. RMSF
      3. Mononucleosis
    •  Metabolic
      1. DKA
      2. Sickle cell disease
      3. SLE / vasculitis
      4. Porphyria
  5.  Toxic
    • Methanol / Heavy metal poisoning
    • Scorpion bite / snake bite / black widow spider bite

Wisecracks:

[1] Why does the WBC have so little utility in abdominal pain?

  • Blood work:
    • “The WBC count is neither sensitive nor specific to be a discriminatory test to establish or rule out serious causes of abdominal pain”
    • Serial WBCs have FAILED at distinguishing surgical from non-surgical pathologies
    • ***WBC is never helpful, except when they indicate immunosuppression***

[2] When is an abdominal x-ray useful in investigating abdominal pain?

  • Has little utility in centres with CT imaging available.
  • I love LITFL: “Gasses, masses, bones, stones” approach
  • Check out: http://lifeinthefastlane.com/investigations/axr-interpretation/
  • Useful for:
    • Query foreign body / body packers/stuffers
      • Shout-out to: http://lifeinthefastlane.com/top-ten-foreign-bodies/
    • Query drug overdose
      • Check out: http://www.ncbi.nlm.nih.gov/pubmed/3813170
      • Iron, mercury, calcium carbonate, chloral hydrate, acetazolamide, potassium chloride tabs
    • Query perforated viscus
    • Pediatric population exceptions
      • Neonates / kids
        • Volvulus / Malrotation
        • NEC
  • Notice that small bowel obstruction and constipation are not suggested indications for getting an abdominal x-ray – especially in centres where CT is available.
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This post was copyedited and uploaded by Michael Bravo (@bravbro).

Adam Thomas

Adam Thomas

CRACKCast Co-founder and newly minted FRCPC emergency physician from the University of British Columbia. Currently spending his days between a fellowship in critical care and making sure his toddler survives past age 5.
Chris Lipp

Chris Lipp

Chris Lipp is one of the founding Fathers for CrackCast. He currently divides his time as an EM Physician in Calgary (SHC/FMC) and in Sports Medicine (Innovative Sport Medicine Calgary). His interests are in paediatrics, endurance sports, exercise as medicine, and wilderness medical education. When he isn’t outdoors with his family, he's brewing a coffee or dreaming up an adventure…..