Renal Infarction 

 

• Thrombotic disease usually affects larger vessels
  • Includes main renal artery
  • Patients with thrombotic disease usually present with hypertension or renal insufficiency
  • Usually results from atherosclerosis
    • But, blunt abdominal trauma may cause intimal tears with subsequent dissection and thrombosis
• Emboli can affect vessels of various sizes depending on the size of the emboli
  • Renal artery emboli usually come from cardiac source
  • Embolic disease usually produces acute symptoms
    • Sudden onset of flank pain
    • Hematuria
    • Proteinuria
    • Fever
    • Leukocytosis
• Causes
  • Trauma
    • Blunt abdominal trauma
    • Traumatic avulsion of renal artery
    • Surgery
  • Embolism
    • Cardiac origin
      • Rheumatic heart disease with arrhythmia
        • Atrial fibrillation
      • Myocardial infarction
      • Prosthetic valves
      • Myocardial trauma
      • Left atrial or mural thrombus
      • Myocardial tumors
      • Subacute bacterial endocarditis
    • Catheters
      • Angiographic catheter manipulation
      • Umbilical artery catheter above level of renal arteries
  • Arterial thrombosis
    • Arteriosclerosis
    • Thrombangitis obliterans
    • Polyarteritis nodosa
    • Syphilitic cardiovascular disease
    • Aneurysms of the aorta or renal artery
    • Sickle cell disease
  • Sudden complete renal vein thrombosis
• Lobar Renal Infarction
  • Early signs
    • Focal attenuation of collecting system
      • Tissue swelling
    • Focally absent nephrogram
      • Triangular with base at cortex
  • Late signs
    • Normal or small kidney(s)
    • Focally atrophied parenchyma with normal interpapillary line
    • Cortical atrophy and irregular scarring are seen as late sequelae
  • CT
    • Subtle renal infarcts are best demonstrated on CT
    • Appear as wedge-shaped, cortically based, hypodense areas
      • Triangular in shape with widest part at the cortex (base of infarct)
    • Non-perfused area corresponding to vascular division
    • Renal swelling may also be seen
    • Cortical rim sign
      • Entire kidney is nonenhancing except for the outer 24 mm of cortex, which are perfused by capsular branches

Two contrast-enhanced axial CT images demonstrate a wedge-shaped
non-enhancing lesion in the right kidney with no perinephric inflammatory stranding

• US
  • Focally increased echogenicity
  • Color flow Doppler aids in diagnosis of renal artery thrombosis
    • There is absence of an intrarenal arterial signal
    • Tardus parvus waveform is seen if incomplete occlusion or collateral supply
  • Nuclear medicine
    • Nuclear imaging shows a photopenic area corresponding to the region of ischemia or infarction

• Chronic Renal Infarction
  • Pathology
    • All elements of kidney atrophied with replacement by interstitial fibrosis
    • Normal or small kidney with smooth contour
    • Globally atrophied parenchyma
    • Diminished or absent contrast material density
  • US
    • Increased echogenicity (by 17 days)
  • Angiography
    • Normal intrarenal venous architecture
    • Late visualization of renal arteries on abdominal aortogram
    • Provides the definitive diagnosis
      • Abrupt termination of vessels or filling defects
      • With end-stage renal artery thrombosis
        • Small kidney with smooth contour, unless multiple small infarcts have occurred independently
• Treatment
  • Anticoagulation
  • Intra-arterial thrombolytic therapy
  • Surgical revascularization

 Dahnert 5^th ed
Amersham