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31st July 2023
Causes
A useful way to categorise and learn the different causes of an acute abdomen is through the pathologies associated with different sites. This will enable you to formulate differential diagnoses based on the location of the pain, which can be seen in the table below.
| Site | Causes |
|---|---|
| Right upper quadrant (RUQ) | Biliary pathology – acute cholecystitis, biliary colic, choledocholithiasis, cholangitis
Duodenal ulcer (and perforated duodenal ulcer) Hepatitis Pyelonephritis Right-sided basal pneumonia |
| Epigastric | Peptic ulcer (gastric or duodenal)
Oesophageal pathology – reflux, stricture, tear, obstruction Acute pancreatitis Gastritis Myocardial infarct (non-abdominal cause, but a crucial differential to be aware of for epigastric pain) |
| Left upper quadrant (LUQ) | Splenic pathology – abscess, ruptured spleen
Gastric ulcer Aortic aneurysm Bowel perforation Pyelonephritis Left-sided basal pneumonia |
| Left lower quadrant (LLQ) | Bowel obstruction
Bowel perforation Mesenteric thrombosis/acute mesenteric ischaemia Ischaemic colitis Aortic aneurysm Diverticulitis Gynaecological pathologies – ruptured ectopic, salpingitis, tubo-ovarian abscess, ovarian torsion, pelvic inflammatory disease Inflammatory bowel disease Renal/ureteric/urethral stones |
| Right lower quadrant (RLQ) | Appendicitis
Gynaecological pathologies – ruptured ectopic, salpingitis, tubo-ovarian abscess, ovarian torsion, pelvic inflammatory disease Mesenteric thrombosis/acute mesenteric ischaemia Ischaemic colitis Renal/ ureteric/urethral stones Mesenteric adenitis Meckel’s diverticulitis Inflammatory bowel disease Perforated caecum Psoas abscess |
Table 1: Classification of causes according to site of pain
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