Cholesterol Emboli

Cholesterol Emboli Syndrome was discussed in the context of acute renal failure and raised lots of interesting issues.

ACUTE RENAL FAILURE:
A standard approach

Prerenal: Volume depletion, hemorrhage, decreased effective circulating volume (CHF, cirrhosis), renal artery stenosis

Renal: Glomerular - Glomerulonephritis (and its associated long list of causes), Acute interstitial nephritis, Acute tubular necrosis (either ischemic or nephrotoxic), Vascular

Postrenal: Obstruction of collecting system or extrarenal drainage

PERIPHERAL EOSINOPHILA
While discussing laboratory findings of AIN, the differential diagnosis of a peripheral eosinophilia was reviewed:
Allergic - rhinitis, asthma, meds.
Infectious - parasitic (helminths), fungal, other
Hematologic - Hypereosinophilia Syndrome, leukemia, lymphoma
Specific Organ Involvement - blood eosinophilia can occur when tissue eosinophilic infiltration is present in pulmonary, GI, derm, cardiac, rheumatologic or renal disease

CHOLESTEROL EMBOLI SYNDROME
Occurs in people with atherosclerotic disease
Spontaneous or as a result of intravascular procedure
Result of cholesterol crystal embolism causing occlusion of multiple small arteries leading to further inflammation and intimal proliferation

Pathology - "ghosts" of cholesterol crystals as they are dissolved during fixation

Symptoms:
Non specific H/A, myalgia, fever
Derm -livedo reticularis (lacy rash), ulceration, gangrene, "blue toe syndrome"
Acute Renal Failure -

GI - intestinal ischemia
Eyes - Hollenhorst plaques (cholesterol crystals in retinal arteries)

Labwork - nonspecific: elevated WBC/ESR, hypocomplementemia, Cr and urine eosinophils (if renal involvement), eosinophila

In the abscence of other symptoms consistent with cholesterol emboli, post angiogram renal failure will often be diagnosed as contrast nephropathy. Ways to try to distinguish the two:

• Presence of other signs of cholesterol emboli (obviously)
• Transient eosinophilia/hypocomplementemia
  
• Persistent renal failure (much less common in contrast nephropathy)

Links to a prosepctive study on CES risk factors and incidence can be found here and the associated editorial here. They found elevated baseline CRP to be an independent risk factor for CES after cardiac cath. Thanks to the facilitator for these.

See a picture of Hollenhorst plaque (from UMich) below: