Abdomen module 7

• Causes of retroperitoneal hemorrhage

  • Trauma
  • Leaking aortic aneurysm
  • Surgery
  • Bleeding neoplasm
  • Vasculitis
  • Misc other causes
• Retroperitoneal hemorrhage


  • May be localized and cause organ displacement or look like an ill defined infiltrative process
  • Patient will have a decreased hematocrit if the bleeding is moderate to severe
  • Sonographic appearance will depend on the age of the bleed
• Retroperitoneal abscess formation


  • May result from surgery, trauma, panc inflammation or perforations of the bowel
  • Patient may present with elevated WBC, fever or abdomen tenderness
• Sonographic appearance of retroperitoneal fluid collections

  • Varies depending on size and age
  • Complex with debris
  • Ill defined
  • Septums
  • Dirty shadowing from gas
• Urinoma


  A walled off collection of extravasated urine that develops after trauma, surgery or subacute or chronic urinary obstruction
• Lymphocele


  A fluid collection associated with renal transplants, the source coming from vessels severed during preparation or recipient vessels
• Primary retroperitoneal tumors (PRT) originate independently within the retroperitoneal space
• Retroperitoneal tumors


  • Can displace kidneys, IVC, aorta and mesenteric vessels, usually anterior
  • May cause deformity of the IVC and bladder
  • May cause obstruction of the kidneys, ureters, extrahepatic biliary bile ducts, IVC, etc.
  • May cause loss of definition of abdominal anatomy
• Lymphoma


  The most common primary retroperitoneal malignancy, can cause painless, progressive lymphadenopathy, splenomegaly and prominent lymph tissue
• Non-Hodgkin's lymphoma


  Lymphocytic, histocytic and B cells in AIDS patients
• Metastases can be from a primary cancer in the abdomen
• Ultrasound is not the modality of choice for visualizing lymph nodes, CT and MRI are better
• Lymphadenopathy


  Enlargement of the lymph nodes caused by inflammatory processes, primary tumor or metastases
• Normal lymph nodes


  • Usually <1cm and not usually seen, accuracy 90% when >2cm
• Things to look for when seeing adenopathy

  • Tumor
  • Infection
  • Extranodal lymphoid masses
• Ascites


  Excessive accumulation of serous fluid in the peritoneal cavity
• Also look for splenomegaly and scan along iliac vessels for pelvic nodes
• Factors affecting distribution of ascites fluid

  • Location
  • Volume
  • Patient position
  • Peritoneal pressure
  • Origination of fluid
  • How fast fluid accumulates
  • Density of fluid
  • Adhesions
  • Bladder fullness
• Sonographic appearance of enlarged lymph nodes

  • >2 cm (should be considered malignant)
  • Usually round with loss of normal configuration
  • Enlarged nodes are homogenous and often hypoechoic
• Serous (Transudative, Benign) ascites

  Appears as echo free fluid regions indented and shaped by the organs and viscera it surrounds or between where it is interposed
• Appearance of para-aortic lymph nodes

  • Individually enlarged or present as lobulated or sheet-like masses
  • Enlarged mantle of nodes surround aorta, have donut ring appearance
  • Elevate the SMA and celiac axis anterior
  • Posterior aortic nodes (floating aorta sign) or IVC will elevate these vessels away from spine and cause caval compression
  • Long images para-aortic nodes draping over aorta can look like aneurysm
• Serous ascites sono findings:
• Appearance of nodes around mesenteric vessels

  • Have sandwich appearance
• Malignant or Inflammatory (Exudative) ascites

  May have atypical findings: Septations, Echogenic debris, Loculations, Thickened interfaces, Matted bowel loops, Does not compress, Does not conform to adjacent organs
• Benign ascites


  Associated with floating bowel
• Appearance of nodes at hepatic hilum


  • Can cause intrahepatic ductal dilatation
• Malignant ascites


  Associated with bowel matted to posterior abdomen wall
• Enlarged lymph nodes


  • Increased intranodal vascularity
  • RI >.7
• Abscess


  Localized collection of pus