An Approach to Acute Abdominal Pain

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					An Approach to Acute Abdominal Pain

    Naresh T. Gunaratnam MD
 Huron Gastroenterology Associates
  Clinical Instructor in Medicine
      University of Michigan

      Anatomic Basis of Pain
• Sensory neuroreceptors in abdomen located
  – mucosa and muscularis propria of hollow
  – on serosal structures like the peritoneum
  – in the mesentery
  – sensory neuroreceptors involved in regulation
    of secretion, motility, and blood flow
  Neuroreceptors in nociception
• Two types of afferent nerve fibers involved
  in the perception of noxious stimuli
  – myelinated A- and unmyelinated C fibers
  – myelinated A- found on skin and muscle
     • mediate sudden sharp well localized pain following
       acute injury
  – C fibers found in muscle, periosteum,
    mesentary, peritoneum and viscera
     • pain usually dull, burning poorly localized, gradual
       onset and long duration
             Stimulants of Pain
• Abdominal visceral nociceptors respond to
  mechanical and chemical stimuli
  – principal mechanical signal is stretch
  – cutting, tearing or crushing of viscera does not
    result in pain
  – mechanoreceptor stimulated with:
     • rapid distention of hollow viscus (intestinal obstruction)
     • forceful muscular contraction (biliray/renal colic)
     • rapid stretching of organ or capusle (hepatic congestion)
                  Types of Pain
• Visceral pain:
   – visceral nociceptors triggered
   – dull, poorly localized pain in midline epigastrium,
     periumblical region or lower midabdomen
   – crampy, burning and gnawing
• Somatoparietal Pain:
   – noxious stimuli to parietal peritoneum
   – intense, well localized (McBurney’s point)
• Referred Pain:
   – pain felt in areas remote to the disease organ
     (subphrenic absess felt as shoulder pain)
          Obtaining a history
• Chronology
  – Sudden onset, well localized= intra-abdominal
    catastrophe (perforated viscus, mesentaric
    infarction, ruptured aneurysm)
  – Progression (appendicitis increases,
    gastroenteritis decreases, colic
  – Duration hours to days more severe than pain
    lasting weeks
          Obtaining a history
• Location
  – may not be specific
  – pain of diaphragmatic irritation will present as
    shoulder pain
  – changes in location may be marker of
    progression (visceralparietal irritation)
  – appendicitis  McBurney’s point
  – perforated ulcer  vague pain to peritonitis
            Obtaining a history
• Aggravating and Alleviating Factors
   – peritonitis  lie motionless
   – renal colic  writhe, unable to find comfortable
   – Fatty foods  biliary colic
   – Pain improves with eating  DU
   – Worse with eating  GU, mesentaric ischemia
• Intensity and character
   – perception of intensity is dependent of point of
     reference of patient
   – not very useful
          Obtaining a history
  – bowel obstruction, renal colic, PID tend to
  – fever, chills  infectious
  – nausea, vomiting with no flatus  bowel
  – dysuria, pregnancy, menstrual history
        Physical Examination
• Still patient  peritonitis
• Writhing patient  colic, bowel obstruction
• Remember the old and the young may
  present very atypically
  – elderly, diabetics, immunocompromised may
    present with minimal symptoms
        Physical Examination
• Severe tenderness with rigidity 
  peritonitis  surgical colleagues
• Mild tenderness  gastroenteritis
• Palpate from areas of least pain to areas
  with most pain
• Peritonitis (shake bed, deep breath)
• Pelvic, Genital and Rectal exam on every
  patient with severe abdominal pain
       Laboratory Evaluation
• CBC, UA, Electrolytes
• Urine and serum pregnancy test in all
  women of reproductive age with lower
  abdominal pain
• LFT , amylase/lipase on all with upper
  abdominal pain
      Radiographic Evaluation
• Plain radiograph
  – upright and supine abdomen and chest x-ray
• Ultrasound on patients with biliary and
  pelvic symptoms
• CT Abdomen and Pelvis
  – evaluates vasculature, inflammation and solid
               The differential
• Acute Cholecystitis
  – cystic duct obstructed, RUQ pain  R scapula
  – Murphy’s sign, LFTS, amylase
• Acute Appendicitis
  –   anorexia, N/V and vague periumbilical pain
  –   6-8 hrs pain migrates to RLQ, fever
  –   Progresses to localized peritoneal irritation
  –   CT useful in diagnosis
            The differential
• Pancreatits
• Acute Diverticulitis
  – most commonly in sigmoid colon
  – symptoms related to inflammation or
  – CT useful early to r/o absess, BE/Endoscopy
    contraindicated  wait 4-6 wks
  – Rx bowel rest, IV abx, surgery for failures
                The differential
   – 70% of cases in adults are post-op
   – adhesions, incarcerated hernias
   – bilious emesis, feculent emesis distal obstruction
   – X-rays  dilated bowel with AF levels
• Perforated DU
   – usually in the anterior duodenal bulb
   – usually sudden acute pain with peritonitis
   – Chest x-ray will show free air under diaphram
             The differential
• Acute mesenteric ischemia
  – intestinal angina (ab pain with eating)
  – “vasculopath” (cad, pvod, ab bruits etc)
  – acute onset of periumbilical abdominal pain out
    of proportion to physical findings
  – CT abdomen, angiogram
  – acidosis may herald intestinal infarction
  – surgery if acute vascular occlusion noted
             The differential
  – acute onset of tearing abdominal pain
  – tender abdominal mass in 90%
  – triad of hypotension, pulsatile ab mass and
    abdominal pain noted in 75%
  – Rx surgically
• Others:
  – endometriosis, salpingitis, tubo-ovarian absess,
    ovarian cysts or torsion, ectopic pregnancy
       Special Circumstances
• Pregnancy
  – appendicitis, cholecystitis, pyelonephritis,
  – adnexal problems (ovarian torsion, ovarian cyst
  – appendicitis 7/1000 pregnancies
  – 3% fetal loss with surgery, but 20% with
    perforated appendix
       Special Circumstances
• Very Young
  – appendicitis and abdominal trauma secondary
    to abuse
  – PID, Meckel’s diverticulum, cystitis, enteritis,
• Very Old
  – symptoms may be subtle
  – compulsive evaluation
       Special Circumstances
• Immunocompromised
  – chemotherapy, organ transplants,
    immunosupression for autoimmune disease,
  – symptoms are subtle
  – unique to immunocompromised host
    (neutropenic enterocolitis, GVH, CMV
    infections, KS, lymphoma/leukemia
       Chronic Abdominal Pain
• 15% of American complain of recurrent
  chroinic abdominal pain
  –   Abdominal pain lasting > 6 months
  –   IBS (Rome Criteria)
  –   Women 70% of all IBS patients
  –   obtain history of abuse (physical/sexual)
  –   exhaustive work-up usually negative
• Obtain detailed history
• Careful exam
• Consider patient circumstances (PVOD,
  diabetes, age, previous ab surgery)
• Early thorough work-up (labs/x-rays)
• Frequent evaluation of progression
• Ask for help if confused!!

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