A 62-year-old woman with a history of smoking presented to the emergency room complaining of acute onset of pain and color change of the left toes. All five of her toes turned purple-blue in color (Figure 8-1). The patient also reported a low-grade fever but denied any precipitating events. Her past medical history was significant for hypertension and coronary artery disease. Her feet were warm, and she had diminished bilateral femoral pulses and absent distal pulses on physical examination. Upon further questioning, the patient admitted to short-distance claudication.

Computed tomographic arteriogram (CTA) showed severely calcified atherosclerotic disease of the abdominal aorta and iliac arteries (Figure 8-2).

The final diagnosis was of blue toe syndrome or atheromatous embolization secondary to severe atherosclerotic disease of abdominal aorta.

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  Usually affects elderly population with multiple risk factors for atherosclerosis, but it may occur in younger individuals with advanced atherosclerosis.

  
  
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  The incidence varies, based on population selection and diagnostic criteria. The unselected autopsy studies show that incidence is 0.85% to 2.4%.^{1,2, and 3} However, autopsy studies performed in selected patients with atherosclerosis and patients who had undergone aortic manipulation showed a prevalence ranging from 12% to 77%.^4,5

  
  
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  There is an increased frequency in males. This may be explained by the difference in the prevalence of atherosclerosis between the genders.

  
  
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  Less likely to occur in blacks than in whites (32:1 ratio).¹ This may represent failure to recognize the pathology because of skin pigmentation.

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  The most important risk factor is established atherosclerosis.

  
  
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  This is a process in which emboli from proximal lesions (plaque) produce ischemia in distal arterial beds.

  
  
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  It may be associated with significant pain and risk of tissue loss such as gangrenous tissue changes (Figure 8-3).

  
  
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  Emboli may consist of thrombus, platelet-fibrin material, or a combination of both. Macroemboli may arise from thrombus originating in aortic or peripheral aneurysms or atheromatous ulcers, or from the dislodgement of atheromatous plaques. Microemboli are platelet-fibrin emboli or cholesterol crystals. Cholesterol crystals are lightweight and tend to be diffused and lodge in arteries as small as 100 to 200 μm.^6,7

  
  
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  Factors that may precipitate lesion (plaque) instability and result in atheroembolization include trauma, vascular surgery, endovascular procedures such as cardiac catheterization, and anticoagulation. Spontaneous embolization was once the most common presentation. With the increase in endovascular interventions, this is now the most frequent underlying cause of distal embolization.¹