read this first: abdominal pain in ED

• abdominal aortic aneurysm
• bowel conditions:
  • see bowel obstruction
    • small bowel obstruction (tends to be more painful early with more vomiting but more poorly localised than LBO)
      • aetiology:
        • adhesions (40-60%)
        • inguinal herniae (10-40%)
        • neoplasms (7-20%) & rare causes eg. gallstones, FB, diverticulitis
      • Emedicine
    • large bowel obstruction (LBO):
      • aetiology:
        • neoplasms (60%) esp. colonic
        • diverticulitis (10-20%)
        • volvulus (5-15%) - sigmoid volvulus more common than caecal volvulus
        • uncommonly, faecal impaction, inflammatory bowel disease (IBD), ischaemic colitis, radiation colitis
    • ischaemic colitis (eg. mesenteric thromboembolism due to AF)
    • other causes of colitis
    • gastroenteritis
    • paralytic ileus or pseudo-obstruction:
      • aetiology:
        • abdominal causes such as appendicitis, pancreatitis, perforated PU, pyelonephritis, retroperitoneal h'age;
        • extra-abdominal causes such as pneumonia, AMI, rib or vertebral trauma
        • metabolic causes - usually hypokalaemia but also hyponatraemia, uraemia, DKA, severe anaemia & hypoproteinaemia
        • drugs such as opiates, anticholinergics, phenothiazines, tricyclics & anti-Parkinsonian
        • rare causes such as CT disorders, amyloidosis, myxoedema
    • in young children, remember, intussusception, malrotation!
• testicular torsion
• uncommonly, DKA

• FBE, U&E, LFT's, amylase, lipase, RBG
• IV fluids as indicated, keep nil orally
• consider urgent bedside US if > 50yrs and suspect abdominal aortic aneurysm (AAA)
• abdominal distension without bowel sounds suggests paralytic ileus but if tenderness is present, this suggests it may be secondary to peritonitis
• high-pitched tinkling bowel sounds suggests mechanical obstruction
• localised tenderness may suggest gangrenous or perforated bowel
• generalised tenderness suggests peritonitis
• check for organomegaly or masses which may suggest malignancy
• PR may reveal empty rectum (suggesive of bowel obstruction), faecal impaction, rectal carcinoma, occult blood or stricture
• FWT urine +/- urine HCG to exclude pregnancy
• consider erect & supine AXR with erect CXR if not pregnant to exclude bowel obstruction and perforated viscus
• if sigmoid volvulus on AXR:
  • discuss with surg. registrar ASAP
  • if evidence of bowel ischaemia (eg. fever, tachycardia, peritonism, or air in bowel wall on plain CT abdo), then needs iv antibiotics and urgent surgery
  • if no evidence bowel ischaemia, usually needs urgent rectal tube to decompress and this will usually resolve the volvulus
• if free gas under the diaphragm on erect CXR:
  • this is a surgical emergency as indicates perforated viscus
  • contact surg. reg. and senior ED doctor ASAP 
• if bowel obstruction on AXR:
  • see small bowel obstruction or large bowel obstruction
• if elderly or patient has AF, consider ischaemic colitis:
  • serum lactate, ABG's
  • plain AXR may show thumb printing of involved colonic segment, & in more advanced cases, there may be gas within the bowel wall, or, if perforation has occurred, free gas in the abdomen on erect CXR.
• if generalised peritonitis:
  • IV fluid resuscitation, FBE, U&E, RBG
  • erect CXR, erect & supine AXR
• if ascites, suspect spontaneous bacterial peritonitis:
  • paracentesis for culture, WCC, protein, glucose, LDH
    • WCC < 250/cu.mm makes SBP unlikely
    • WCC > 500 is highly specific for SBP
    • WCC > 10,000 or protein > 1g/dL or glucose < 50mg/dL or elevated LDH greatly increase the risk that the peritonitis is from a local cause
  • early empirical antibiotics eg. cefotaxime but still high mortality.
  • urgent surg. consult
  • IV anti's as per surg. consult.
• if cause is not evident, consider urgent abdo. CT and discuss with surg. reg and radiology oral & iv contrast
  • check renal function and if on metformin before giving iv contrast.
  • CT scan is more sensitive for small bowel obstruction than AXR which is only 45-70% sensitive - the fluid and gas in the bowel may negate need for oral contrast for CT scanning