The etiology of abdominal pain

Abdominal Pain July 3rd, 2007 Justin Harberson,MD Overview A wide variety of disease states can cause abdominal pain. etiology of abdominal pain can be determined through the combination of historical factors, physical findings, lab values, and radiologic findings.  The Acute vs Chronic Abdominal Pain or chronic?  Acute abdominal pain may be the symptom of a life threatening condition and requires efficient, expeditious evaluation.  Chronic abdominal pain is a very common complaint, often more of an outpatient evaluation, often more difficult to determine the origin of.  Acute Location, location, location    Patients often have a difficult time identifying the precise location of abdominal pain. Sensation in the abdominal viscera is mediated by a network of afferent C fibers which are stimulated by stretching, inflammation, or ischemia. A single splanchnic afferent nerve may provide the sensory input from several organs and may enter the spinal cord at more than one level. Location, location, location embryologically most organs are derived from midline structures and retain bilateral innervation.  As a result of bilateral innervation, pain is often reported as midline, and poorly lateralized.  The exception to this is in the most lateralized organs– gallbladder, kidneys, ureters, ovaries.  Further, Location, location, location originating from the parietal peritoneum is much better localized.  The sensation of this pain is mediated by somatic afferent nerves.  Parietal peritoneum has a much denser network of nerve fibers than the abdominal viscera, it also lacks the bilateral innervation found in the abdominal viscera.  Pain Location, location, location    Referred pain is pain localized to a site distant from the abdominal organ from which the pain originates. This occurs because of the common site of entry into the spinal cord of cutaneous sensory neurons and abdominal visceral afferents. Cutaneous and visceral afferents terminate on the same secondary neuron within the dorsal horn of the spinal cord, resulting in misinterpretation by the brain of the correct origin of the stimulus. Location, location, location pain represents the change in stimulation from visceral afferents to somatic afferents.  This is best represented by acute appendicitis which may start as periumbilical pain and migrates to the right lower quadrant (McBurney’s point) as the parietal peritoneum becomes irritated.  Migrating Evaluating Acute Abdominal Pain Course  Quality of the Pain  Aggravating and alleviating factors  Physical Exam  Lab tests  Diagnostic tests  Time Time Course of pain can be highly suggestive of its etiology.  Sudden Onset (seconds to minutes) may represent a catastrophic event.  Examples of this include perforated ulcer, ruptured AAA, acute MI, ruptured ectopic pregnancy, mesenteric infarction, Boerhaave’s esophagus, ruptured abscess.  Onset Time Course  Rapidly progressive abdominal pain (1-2 hours) may include biliary colic, cholecystitis, pancreatitis, diverticulitis, small bowel obstruction, appendicitis, or mesenteric ischemia. Time Course  Gradual onset (over several hours) of abdominal pain may be due to appendicitis, cholecystitis, diverticulitis, PUD, pyelonephritis, intra-abdominal abscess, ectopic pregnancy (before rupture), SBO, neoplasms with perforation, PID, incarcerated hernia. Quality of the Pain     Certain characteristics of the type and severity of the pain may suggest its etiology. Peptic ulcer disease often presents with mild to moderate, dull gnawing mid-epigastric pain. Perforated ulcers or mesenteric infarction present with severe, intense pain. Severe “tearing” pain is associated with dissecting aneurysms. Quality of the Pain refers to episodic pain with intervening pain-free intervals.  “Renal colic” can present this way.  “Biliary colic” is a misnomer– biliary pain typically presents with continuous, steady pain (without pain free intervals)  “Colic” Aggravating and Alleviating Factors that precipitate or improve the pain can help determine the cause.  For instance, antacids can relieve the pain associated with PUD or esophagitis.  Does eating make pain better or worse? (better with duodenal ulcers, worse with gastric ulcers).  Worse after fatty foods? (Biliary colic)  Actions Aggravating and Alleviating Factors    Does defecation improve the pain? (Suggests colonic source) Does walking around or sitting up improve the pain? (retroperitioneal processes are improved with leaning forward, pain under the diaphragm can be relieved with standing, walking) Does moving, coughing, laughing, or sneezing make the pain worse? (suggests peritoneal signs). Physical Examination signs can be highly suggestive– tachycardia and hypotension suggests ruptured AAA or sepsis.,  Low grade fever suggests diverticulitis, appendicitis, or cholecystitis.  High fever suggests cholangitis, perforated viscus, peritonitis  Vital Physical Examination best exam is performed prior to administration of pain medicines.  Inspect the abdomen– is it distended, is it tense?  Ausculate first– absence of bowel sounds suggests peritonitis, few high pitched bowel sounds indicates bowel obstruction, hyperactive bowel sounds can indicate gastroenteritis.  The Physical Examination     Percussion– pain produced by percussion suggests peritonitis, tympany can indicate a bowel obstruction. Palpation– start at the point farthest from the most painful area. Voluntary guarding– tensing/rigidity of the abdominal wall which relaxes with a deep breath. Involuntary guarding– does not relax with deep inspiration (suggests peritoneal inflammation) Physical Examination   The presence of a a focal area of pain narrows the list of possible organs. Tenderness at McBurney’s point highly suggests appendicitis. Physical Examination   Cholecysitis is typically localized to the RUQ. Murphy’s sign refers to pain elicited by deep inspiration during palpation of the right subcostal margin. Physical Examination  Patients with complaints of severe, worsening abdominal pain and a relatively unimpressive abdominal exam should be suspected of having mesenteric ischemia or infarction. Physical Examination pelvic exam is mandatory in female patients (looking for evidence of salpingitis or an adnexal mass).  A rectal exam may reveal focal tenderness from an abscess or appendicitis.  Inspect the perineum, especially in patients with DM or poor hygiene. A LAB tests patient who presents with abdominal pain should have CBC with diff, BMP, LFTs, Amylase/Lipase, UA, and beta-HCG (all females of child bearing age).  Cardiac enzymes  Lactate  Each Diagnostic Tests patient who presents with acute abdominal pain needs radiologic imaging.  Upright PA and Lat CXR and obstruction series.  CT scans often reveal the problem  Ultrasound  Every Further evaluation  Never hesitate to consult GI or surgery (earlier is better). Chronic Abdominal Pain     This is a very common complaint, more likely to be seen in the outpatient setting. Arbitrary when to classify pain as chronic– usually after months. The vast majority of patients with chronic abdominal pain will have a functional disorder (IBS). The initial workup of chronic abdominal should be focused on differentiating a benign functional disorder from organic pathology. Chronic Abdominal Pain  May be divided into chronic intermittent abdominal pain and persistent abdominal pain. Chronic Intermittent Abdominal Pain that occurs in an intermittent pattern– lasting from minutes to hours with intervening asymptomatic periods may be caused by several categories of (potentially correctable) disorders.  Careful history, physical exam, laboratory, and radiographic studies  Pain Chronic Intermittent Abdominal Pain Tract disease (cholelithiasis, choledocholithiasis, and sphincter of Oddi dysfunction) leads to intermittent RUQ pain.  Acute on Chronic Pancreatitis causes chronic intermittent abdominal pain.  Intermittent SBO and mesenteric ischemia cause chronic post-prandial pain.  Biliary Chronic Intermittent Abdominal Pain Intermittent Porphyria (rare)  Endometriosis (monthly)  Celiac disease  Inflammatory Bowel Disease  Heavy metal poisoning  Arcuate ligament syndrome  Acute Persistent Chronic Abdominal Pain is pain that is present much or all of the time.  May be related to a functional disorder or underlying chronic disease.  This Persistent Chronic Abdominal Pain = chronic upper abdominal pain and discomfort between the xiphoid process and the umbilicus.  Causes include GERD, PUD, Gastric CA, Medications, and Functional dyspepsia.  Gastroparesis can cause chronic postprandial abdominal pain, bloating, nausea, and vomiting.  Dyspepsia Persistent Chronic Abdominal Pain disorders include IBS and functional dyspepsia.  IBS = pain/bloating associated with change in bowel habits (diarrhea or constipation).  Functional dyspepsia = Bothersome postprandial fullness, early satiation, epigastric pain, epigastric burning.  Functional Persistent Chronic Abdominal Pain diagnosis of functional disorders in patients older than 50y/o should be made with caution.  Pain that is associated with weightloss and anorexia should raise the possibility of malignancy.  The Chronic Abdominal Pain should include a thorough physical exam as well as appropriate lab and radiography  EGD with biopsies and diagnostic colonoscopy may also be indicated.  Other specialized GI testing (manometery pH testing, etc) may be indicated.  Workup CASE #1 y/o obese female presents with midepigastric pain that awoke her from sleep. The pain radiates to her back and has lasted for 5 hours without relief. On exam she is afebrile, tender in the midepigtastrium, with no rebound or guarding.  Differential?  What tests would you order?  45 Case #2  28 y/o female with Crohns disease presents with fever, diarrhea, and severe RLQ abdominal pain. On exam she is febrile (102) and exquisitely tender in the right lower quadrant– the patient puts her finger on the exact spot. She was recently hospitalized and treated with a Crohns flare with a quinolone for 10 days.   Differential? What tests would you order? Case #3  60y/o male history of CAD s/p CABG, DM, and osteoarthritis presents c/o 2 weeks abdominal bloating and “heartburn.” He has taken maalox and tums with some relief.  Differential?  Tests? Case #4  22 y/o female presents complaining of abdominal bloating and cramps. Worse with stress. Her bowel habits are sometimes “really explosive diarrhea” or “I can’t go for a week”  Differential?  Tests? Case #5  50 y/o female with longstanding DM presents c/o gradually worsening midepigastric fullness/pain, occasional Nausea + Vomiting. The pain is postprandial and sometimes worse with activity.  Differential?  Tests? END