Atheromatous emboli to the kidneys

Atheromatous embolization

Atheromatous embolization is a multisystem disease complicating advanced atherosclerosis. It occurs most often as a complication of angiography, an endovascular procedure or cardiovascular surgery. Atheromatous embolization can present in a subtle manner where it is often under-recognized, or with catastrophic results including myocardial infarction, strake or acute renal failure. It may mimic other disease processes and often goes underdiagnosed and undertreated. A high clinical suspicion is the key to diagnosis. Atheromatous embolization results in significant morbidity and mortality; therefore, early recognition followed by aggressive management may help to prevent end-organ damage and improve overall clinical outcomes. Management strategies should include risk factor modification, prevention of further insults by discontinuing or avoiding predisposing factors, supportive treatment and interventional or surgical approaches to remove the atheroembolic source. Atheromatous embolization is expected to increase as our population ages and the epidemics of diabetes mellitus and obesity increase.

Eosinophiluria in atheroembolic renal disease

PURPOSE AND PATIENTS

Eosinophiluria has been reported in acute interstitial nephritis and other renal diseases, but its presence in atheroembolic renal disease (AERD) has not been previously established. AERD has been identified as a cause of acute and chronic renal failure, particularly in elderly patients with advanced atherosclerosis and in those patients who have undergone manipulation or intervention of the abdominal aorta, renal artery, or coronary artery. The definitive diagnosis is made by renal biopsy. However, many patients are too acutely ill to tolerate renal biopsy and, in recent years, peripheral eosinophilia, hypocomplementemia, and thrombocytopenia have been recognized in association with AERD. Previous studies have reported that AERD is associated with an inactive renal sediment and an absence of urine eosinophils. We reviewed our experience over a 4-year period with 24 patients with renal biopsy-proven AERD.

RESULTS

Urine eosinophils were evaluated in nine patients to help determine the cause of their renal deterioration. Seven of these patients presented with evidence of vascular disease. Three patients had procedures involving manipulation of the abdominal aorta. Physical examination revealed findings of atheroembolism in three of nine patients. Overall, eight of nine patients had a positive Hansel's stain for eosinophiluria. Six of eight patients had more than 5% of their urinary white cell count as eosinophils. The reason for failure of previous studies to detect eosinophiluria in AERD is unclear but may have been related to the use of Wright's stain instead of Hansel's stain.

CONCLUSION

In the evaluation of acute renal insufficiency, eosinophiluria may indicate AERD in addition to the other known causes for this finding.

Cholesterol crystal embolization: a review of 221 cases in the English literature

Cholesterol crystal embolization (CCE) frequently presents with nonspecific manifestations that mimic other systemic diseases. The authors reviewed 221 cases of histologically proven CCE in the English literature to define the clinical, laboratory, and pathologic characteristics of this disorder. CCE affected predominantly elderly males (mean age sixty-six) with a frequent history of hypertension (61%), atherosclerotic cardiovascular disease (44%), renal failure (34%), and aortic aneurysms (25%) at presentation. At least one possible predisposing factor was present in 31% and included operative and radiological vascular procedures and the use of anticoagulants. Cutaneous findings (34%) and renal failure (50%) were two of the most common clinical findings throughout the course of CCE. The nonspecific signs and symptoms included: fever (7%), weight loss (7%), myalgias (4%), and headache (3%). Premortem diagnoses were established in 31% of patients most commonly by biopsy of the muscle, skin, and kidney. Mortality was high (81%) and was most commonly due to multifactorial, cardiac, and renal etiologies. The authors conclude that CCE should be strongly considered in elderly patients with atherosclerotic vascular disease who have the onset of renal insufficiency and cutaneous manifestations. CCE may be confirmed by a skin or muscle biopsy.

The clinical spectrum of renal cholesterol embolization

Renal cholesterol embolization can occur spontaneously or as a complication of aortic surgery or major vessel angiography in patients with diffuse atherosclerosis. The demonstration of characteristic cholesterol crystals in tissue biopsy specimens is a pathognomonic finding. However, renal cholesterol embolism may be clinically diagnosed when renal failure develops after known inciting factors or together with systemic manifestations of atheromatous embolization such as lower extremity livedo reticularis, focal digital ischemia or retinal embolism. Previous investigators have emphasized the progressive nature of renal insufficiency due to cholesterol embolism, its poor prognostic significance and almost uniformly fatal outcome. In this report, we describe five additional patients with renal cholesterol embolization. In three of them only moderate renal insufficiency developed, and kidney function subsequently improved in all. In two patients the condition progressed to end-stage renal disease; one died with chronic renal failure whereas the other patient required four months of hemodialysis before kidney function eventually improved. Thus, cholesterol embolization may produce a spectrum of renal functional impairment. In some patients there is only a moderate loss of renal function with subsequent improvement; in others renal failure ensues. In this latter group, eventual return of kidney function can occur even after a prolonged period of renal insufficiency.