the patient with acute abdominal pain in the ED

see also: general surgery;

• NICS - pain medication for acute abdominal pain (pdf)
• Western Health ED: pain medications instruction sheet (pdf)
• Western Health ED: adult abdominal pain discharge instruction sheet (pdf)

• move patient to a resuscitation cubicle if available
• iv access
• iv N Saline as indicated
• supplemental oxygen
• iv analgesia (eg. morphine)
• notify surgical registrar ASAP
• consider bladder scan to exclude acute urinary retention
• send bloods for:
  • FBE, U&E, glucose, LFT's, lipase, CRP, INR, group and hold
  • HCG if female in fertile age range (hint: you CAN use blood on a urine pregnancy test strip - this might be life saving!)
  • lactate and ABG if risk of ischaemic bowel (eg. AF or unexplained increasing tachycardia with minimal abdominal signs)
  • troponin if chest pain or upper abdominal pain - particularly if diabetic
• ECG
• rapid bedside abdominal US to help exclude AAA and to look for free fluid which may suggest ruptured ectopic
• erect CXR (to detect free air as a sign of perforated viscus) and supine AXR if NOT pregnant
• consider NGT if persistent vomiting
• consider IDC if critically ill and need to monitor urine output
• urinalysis
• if febrile or possibly septic, and still unstable:
  • see sepsis and septic shock
• if diagnosis is unclear and the patient continues to be very unwell:
  • a CT chest and abdo/pelvis should be considered, preferably with contrast if eGFR and time allows, otherwise as a non-contrast CT to avoid delay in diagnosis of an occult life threatening condition.

• abdominal pain is a clinical risk RED FLAG condition:
  • abdominal pain is a major clinical risk area as it is common and has a multitude of relatively common potential life-threatening conditions which can easily be missed leading to delay in diagnosis and increased morbidity & sometimes mortality. 
• important points to assist in Mx of this often perplexing presentation:
  • try to get as accurate as possible the region of maximal pain/tenderness:
    • this treatise assumes you can do this and thus you can then go to the appropriate region:
      • RUQ
      • epigastric
      • LUQ
      • central / periumbilical / generalised
      • RIF
      • suprapubic
      • LIF
      • flank pain
      • if the abdomen is tender all over and rigid - this highly suggests a life threatening generalised peritonitis such as perforated viscus, ruptured ectopic, intra-abdominal sepsis, etc - see resuscitation as above
      • when multiple regions are tender and a cause cannot be found in women, consider endometriosis, especially if PH of this or the pain is recurrent or also radiates down the leg
• ask about the pattern of pain, in particular:
  • speed of onset (rapid onset suggests colic type or rupture, whereas gradual onset suggests inflammatory)
  • preceded by chest pain
    • consider aortic dissection - late presentations often have vomiting with raised inflammatory markers +/- fever and hypotension and may progress to back pain
    • acute myocardial infarction (AMI/STEMI/NSTEMI) may present with epigastric pain
    • biliary colic often presents as chest or back pains
  • constant vs colicky
    • colicky cramping pains usually mean the patient will tend to roll around rather than stay motionless to control the pain, and this type of pain is usually caused by muscle spasms such as in an obstructed tubular structure (eg. biliary colic, renal colic, small bowel obstruction or large bowel obstruction), or uterine cramping pain.
    • constant pain with patient preferring not to move suggests peritonitis
  • is there meleana or rectal bleeding?
    • see GIT bleeding
  • is there bloody diarrhoea?
    • this suggests either bacterial gastroenteritis (Campylobacter, shigella, Clost. difficile), diverticulitis, ischaemic colitis or inflammatory bowel disease (IBD)
  • is there mod-severe watery diarrhoea?
    • this suggests gastroenteritis:
      • viral, E.coli, Salmonella, Staph, aureus, Cryptosporidium, giardiasis (usually frothy, foul-smelling), etc
    • if myalgias & paraesthesiae after eating fish, consider Ciguatera fish poisoning 
    • but remember pelvic appendicitis
• could the patient be pregnant?
  • this is extremely important as not only does one need to exclude ectopic pregnancy, etc but one should make sure patient is not pregnant BEFORE ordering Xrays.
• check the skin for shingles!
• could there be an extra-abdominal cause?
  • eg. pneumonia, diabetic ketoacidosis (DKA) or acute myocardial infarction (AMI/STEMI/NSTEMI)?
• are there risk factors for certain conditions?
  • known diabetes - acute myocardial infarction (AMI/STEMI/NSTEMI) or diabetic ketoacidosis (DKA) presenting as abdo. pain
  • past history of biliary disease, pancreatitisor renal colic
  • past abdominal surgery with risk of small bowel obstruction, etc
  • PH inflammatory bowel disease (IBD) such as Crohn's disease
  • atrial fibrillation - risk of ischaemic_colitis
  • immunosuppressed patients at higher risk of Salmonella, etc, and likely to have more rapid progression of divericulitis, etc.
  • cirrhosis patients at risk of spontaneous bacterial peritonitis
  • the elderly are more likely to have diverticulitis, ischaemic colitis, large bowel obstruction and abdominal aortic aneurysm (AAA)
  • PH or FH sickle cell disease (SCD), Familial Mediterranean Fever
  • thrombophilia or recent A-Z Covid-19 vaccine - consider thrombosis with thrombocytopenia syndrome (TTS / VITT / VIPIT) and splanchnic vein thrombosis (SVT)
• is the problem really faecal soiling or incontinence? - you may need to do a PR!
  • see faecal impaction, faecal incontinence
• remember to get early senior consult:
  • especially if patient is unwell or elderly as these patients are particularly at risk of increased morbidity with delay in diagnosis and are often the most difficult patients to assess.
  • junior staff should discuss all patients with abdominal pain who are over 65 years age with a surgical registrar or a senior ED doctor.
• always check inguinal region & scrotum:
  • exclude herniae & testicular torsion, patients may be too embarrassed to tell you!
• don't just put the diagnosis as “constipation” or “gastro” until you have excluded other major causes, and in particular, if the patient is febrile or has a raised WCC, do not attribute these to “constipation”
• remember atypical presentations:
  • pelvic appendicitis presents with minimal abdo. signs but often with fever, diarrhoea
  • appendicitis in children under 5yrs or the elderly can be especially difficult to diagnose
  • ischaemic colitis often has severe pain but minimal abdominal signs
  • diverticulitis may be right-sided
  • many non-urological conditions can cause dysuria & frequency such as appendicitis, diverticulitis, endometriosis, PID
  • although inflammatory bowel disease (IBD) is most commonly seen in pts under 30yrs, a 2nd peak of onset occurs in the 50's.
  • biliary conditions commonly present with R pain radiating to back, but uncommonly may present with left lateral chest pain but RUQ tenderness!
  • pyelonephritis can often present as RUQ tenderness - check the urinalysis!
• remember some things may be red herrings or confuse the picture:
  • gallstones are common incidental findings - 20% females & 8% males over age 40yrs have them
  • renal calculi does not necessarily mean renal colic, it could be drug seeking behaviour, or another cause
  • air-fluid levels on AXR may represent paralytic ileus rather than bowel obstruction
  • pleural effusions may be secondary to pancreatitis, cholecystitis, etc.
  • a normal WCC, LFT's or ultrasound does not exclude cholecystitis or appendicitis
  • a normal lipase or amylase does not exclude pancreatitis - it may be too early in the course, or it may be chronic.
  • a negative urine pregnancy test or recent menses does not exclude ectopic pregnancy - one should do a serum HCG for more confidence.
• a few paediatric points:
  • acute testicular pain should have paed. consultant notification within minutes - do not arrange an US!
  • avoid abdominal Xrays or CT where possible as even a plain AXR has radiation dose equivalent to some 15-20 CXR's
  • blood tests are usually unhelpful unless the patient is very unwell with generalised peritonitis and likely to need substantial fluid Rx
  • remember intussusception, malrotation, Meckel's diverticulum, and, in girls over 8yrs, torsion of ovary