Abdominal pain DDx


Acute abdomen is abdominal pain in the presence of tenderness and rigidity and is a surgical emergency. Abdominal pain can be considered in terms of surgical, Ob/Gyn and medical causes.

  • The causes of abdominal pain are best dealt with according to the different regions of the abdomen. If pain is localised to a specific region of the abdomen, also consider nearby regions as the possible source of the pain.
  • Don’t forget the abdominal wall as a source of the pain (e.g. haematomas, herpes zoster, etc) and that abdominal pain may originate from above the diaphragm!
  • See also medical causes of abdominal pain.


Generalised abdominal pain with tenderness and rigidity

  • perforated peptic ulcer
  • perforation of other intra-abdominal organs
  • AAA rupture
  • aortic dissection
  • pancreatitis
  • ectopic pregnancy
  • ischaemic gut

Central/ peri-umbilical pain without abdominal signs

  • acute small bowel ischemia
  • acute appendicitis
  • acute small bowel obstruction
  • acute pancreatitis
  • testicular torsion
  • medical causes of abdominal pain

Epigastric pain


  • gastritis
  • peptic ulcer
  • reflux oesophagitis
  • pancreatitis
  • cancer (gastric, pancreatic)
  • Boerhaave syndrome (esophageal rupture)
  • dyspepsia
  • irritable bowel syndrome

Pain from nearby areas

  • abdominal: central, RUQ pain
  • cardiac: e.g. myocardial infarction, pleuritis
  • pulmonary: e.g. pneumonia, pleurisy

Right hypochondrium/ upper quadrant pain

Gall bladder

  • biliary colic
  • cholecystitis
  • cholangitis


  • hepatitis
  • hepatomegaly (e.g. liver congestion in right heart failure)
  • hemorrhage into hepatic tumour
  • trauma
  • hepatic or subdiaphragmatic abscess
  • Fitz-Hugh-Curtis syndrome (peri-hepatitis due to PID)
  • Pre-eclampsia and HELLP

Other gastrointestinal

  • appendicitis with high appendix (e.g. pregnancy)
  • perforated or penetrating duodenal ulcer
  • colon cancer

Pain from nearby areas

  • abdominal: epigastric, central, RIF, loin, groin pain
  • right lower lobe pneumonia, pleurisy or other lung disease
  • subphrenic abscess
  • acute pyelonephritis

Left hypochondrium/ upper quadrant pain

  • pancreatitis
  • subphrenic abscess
  • diverticulitis
  • ruptured spleen
  • acute pyelonephritis
  • leaking aneurysm of the splenic artery
  • acute gastric distention

Right iliac fossa pain


Reproductive (female)

  • ectopic pregnancy
  • acute ovarian event (cyst rupture, hemorrhage, torsion)
  • Mittelschmerz (ovulation pain mid-cycle)
  • Pelvic inflammatory disease
  • Endometriosis

Reproductive (male)

  • seminal vesiculitis
  • undescended testicle pathology


  • renal colic
  • UTI

Pain from nearby areas

  • abdominal: RUQ, central, groin pain
  • hip pathology
  • psoas abscess
  • rectus sheath haematoma
  • right lower lobe pneumonia

Left iliac fossa pain


  • diverticulitis
  • colitis
  • colon cancer
  • constipation
  • irritable bowel syndrome

Reproductive (female)

  • ectopic pregnancy
  • acute ovarian event (cyst rupture, hemorrhage, torsion)
  • Mittelschmerz (ovulation pain mid-cycle)
  • Pelvic inflammatory disease
  • Endometriosis

Reproductive (male)

  • seminal vesiculitis
  • undescended testicle pathology


  • renal colic
  • UTI

Pain from nearby areas

  • abdominal: LUQ, central, groin pain
  • hip pathology
  • psoas abscess
  • rectus sheath haematoma
  • left lower lobe pneumonia

Suprapubic pain

  • urinary retention
  • cystitis
  • uterine in origin (e.g. PID, fibroid, menstruation)
  • origin from RIF and/ or LIF causes

Loin pain

Renal tract

  • infection e.g. pyelonephritis
  • obstruction, e.g. renal colic
  • renal carcinoma
  • renal vein thrombosis
  • polycystic kidney disease
  • adrenal hemorrhage


  • retroperitoneal hemorrhage
  • retroperitoneal infection
  • vertebral pathology

Groin pain

  • renal calculi
  • scrotal pain e.g. testicular torsion, epididymo-orchitis, trauma
  • inguinal hernia
  • hip pathology
  • pelvic fracture

CCC Differential Diagnosis Series


Anosmia, Ataxia, Blepharospasm, Bulbar and Pseudobulbar palsy, Central Pontine Myelinosis, Cerebellar Disease, Chorea, Cranial nerve lesions, Dementia, Dystonia, Exophthalmos, Eye trauma, Facial twitches, Fixed dilated pupil, Horner syndrome, Loss of vision, Meningism, Movement disorders, Optic disc abnormality, Parkinsonism, Peripheral neuropathy, Radiculopathy, Red eye, Retinal Haemorrhage, Seizures, Sudden severe headache, Tremor, Tunnel vision


Bronchial breath sounds, Bronchiectasis, High airway pressures, Massive haemoptysis, Sore throat, Tracheal displacement


Atrial Fibrillation, Bradycardia, Cardiac Failure, Chest Pain, Murmurs, Post-resuscitation syndrome, Pulseless Electrical Activity (PEA), Pulsus Paradoxus, Shock, Supraventricular tachycardia (SVT), Tachycardia, VT and VF, SVC Obstruction


Abdominal distension, Abdominal mass, Abdominal pain, Asterixis, Dysphagia, Hepatomegaly, Hepatosplenomegaly, Large bowel obstruction, Liver palpation abnormalities, Lower GI haemorrhage, Malabsorption, Medical causes of abdominal pain, Rectal mass, Small bowel obstruction, Upper GI Haemorrhage


Genital ulcers, Groin lump, Scrotal mass, Urine colour, Urine Odour, Urine transparency


Arthritis, Shoulder pain, Wasting of the small muscles of the hand


Palmar erythema, Serious skin signs in sick patients, Thickened Tethered Skin, Leg ulcers, Skin Tumour, Acanthosis Nigricans


Diabetes Insipidus, Diffuse Goitre, Gynaecomastia, Hirsutism, Hypoglycaemia, SIADH, Weight Loss




Floppy infant 


Anaphylaxis, Autoimmune associated diseases, Clubbing, Parotid Swelling, Splinter haemorrhages, Toxic agents and abnormal vitals, Toxicological causes of cardiac arrest


CHEST: Atelectasis, Hilar adenopathy, Hilar enlargement on CXR, Honeycomb lung, Increased interstitial markings, Mediastinal widening on mobile CXR, Pulmonary fibrosis, Pseudoinfiltrates on CXR, Pulmonary opacities on CXR,
Gas on abdominal X-ray, Kidney mass,
Intracranial calcification, Intracranial structures with contrastVentriculomegaly,
OTHER: Pseudofracture on X-Ray


LOW: Anaemia, Hypocalcaemia, hypochloraemia, Hypomagnesaemia

HIGH: Bilirubin and Jaundice, HyperammonaemiaHypercalcaemia, Hyperchloraemia, Hyperkalaemia, Hypermagnesaemia

ACID BASE: Acid base disorders, Resp. acidosis, Resp. alkalosis,

Creatinine, CRP, Dipstick Urinalysis, Laboratory Urinalysis, Liver function tests (LFTs), Pleural fluid analysis, Urea, Urea Creatinine Ratio, Uric acid, Urinalysis, Urine Electrolytes


CCC 700 6

Critical Care


Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of three amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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