Abdominal aortic aneurysm differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Hardik Patel, M.D. Ramyar Ghandriz MD[3]

Overview

An abdominal aortic aneurysm should be differentiated from other causes of abdominal pain such as acute cholecystitis, gastrointestinal bleeding, perforated peptic ulcer, ischemic bowel, nephrolithiasis, pyelonephritis, appendicitis, cholelithiasis, large bowel obstruction, small bowel obstruction, pancreatitis, musculoskeletal pain, myocardial infarction, and urinary tract infection.

Differentiating Abdominal Aortic Aneurysm from other Diseases

• A patient becomes symptomatically after abdominal aortic rupture, so the differentiation is according to the rupture which causes acute abdomen signs and symptoms.
• Non-symptomatic AAA is diagnosed through abdominal ultrasound with no other differentials.
• In a patient with a suspected abdominal aortic aneurysm, the following conditions also need to be considered:

• • Acute cholecystitis
  • Gastritis and peptic ulcer disease
  • Gastrointestinal bleeding
  • Ischemic bowel
  • Diverticulitis
  • Nephrolithiasis
  • Pyelonephritis
  • Appendicitis
  • Cholelithiasis
  • Large bowel obstruction
  • Small bowel obstruction
  • Pancreatitis
  • Musculoskeletal pain
  • Myocardial infarction
  • Urinary tract infection in women

Classification of acute abdomen based on etiology Presentation Clinical findings Diagnosis Comments Fever Rigors and Chills Abdominal Pain Jaundice Hypotension Guarding Rebound Tenderness Bowel sounds Lab Findings Imaging Common causes of Peritonitis Spontaneous bacterial peritonitis + Diffuse − − − − Hypoactive Ascitic fluid PMN>250 cells/mm³ Culture: Positive for single organism Ultrasound for evaluation of liver cirrhosis - Perforated gastric and duodenal ulcer + Diffuse − + + + N Ascitic fluid LDH > serum LDH Glucose < 50mg/dl Total protein > 1g/dl Air under diaphragm in upright CXR Upper GI endoscopy for diagnosis Acute suppurative cholangitis + + RUQ + + + + ± Acute cholangitis + − RUQ + − − − N Abnormal LFT Ultrasound shows biliary dilatation Biliary drainage (ERCP) + IV antibiotics Acute cholecystitis + RUQ + − − Hypoactive Hyperbilirubinemia Leukocytosis Ultrasound shows gallstone and evidence of inflammation Murphy’s sign Acute pancreatitis + Epigastric ± − − N Increased amylase / lipase Ultrasound shows evidence of inflammation Pain radiation to back Acute appendicitis + RLQ − + + Hypoactive Leukocytosis Ultrasound shows evidence of inflammation Nausea & vomiting, decreased appetite Acute diverticulitis + LLQ ± + − Hypoactive Leukocytosis CT scan and ultrasound shows evidence of inflammation Hollow Viscous Obstruction Small intestine obstruction − Diffuse − + ± Hyperactive then absent Leukocytosis Abdominal X ray Nausea & vomiting associated with constipation, abdominal distention Gall stone disease/Cholelithiasis ± − Volvulus - Diffuse - + - Hypoactive Leukocytosis CT scan and abdominal X ray Nausea & vomiting associated with constipation, abdominal distention Biliary colic - RUQ + - - N Increased bilirubin and alkaline phosphatase Ultrasound Nausea & vomiting Renal colic - Flank pain - - - N Hematuria CT scan and ultrasound Colicky abdominal pain associated with nausea & vomiting Vascular Disorders Ischemic causes Mesenteric ischemia ± Periumbilical - - - Hyperactive Leukocytosis and lactic acidosis CT scan Nausea & vomiting, normal physical examination Acute ischemic colitis ± Diffuse - + + Hyperactive then absent Leukocytosis CT scan Nausea & vomiting Hemorrhagic causes Ruptured abdominal aortic aneurysm - Diffuse - - - N Normal CT scan Unstable hemodynamics Intra-abdominal or retroperitoneal hemorrhage - Diffuse - - - N Anemia CT scan History of trauma Gynaecological Causes Fallopian tube Acute salpingitis + LLQ/ RLQ − ± ± N Leukocytosis Pelvic ultrasound Vaginal discharge Ovarian cyst complications and endometrial disease Torsion of the cyst - RLQ / LLQ - ± ± N Increased ESR and CRP Ultrasound Sudden onset severe pain with nausea and vomiting Endometriosis - RLQ/LLQ - +/- +/- N Normal Laproscopy Menstrual-associated symptoms, pelvic symptoms Cyst rupture - RLQ / LLQ - +/- +/- N Increased ESR and CRP Ultrasound Sudden onset severe pain with nausea and vomiting Pregnancy Ruptured ectopic pregnancy - RLQ / LLQ - - - N Positive pregnancy test Ultrasound History of missed period and vaginal bleeding Functional Irritable Bowel Syndrome - Diffuse - - - - N Clinical diagnosis ROME III/IV criteria Pharmacologic studies based criteria - High dietary fiber Osmotic laxatives Antispasmodicdrugs References