Alternate Names: Renal disease - atheroembolic; Cholesterol embolization syndrome; Atheroemboli - renal; Atherosclerotic disease - renal

Causes and Risks: Atheroembolic renal disease involves damage and destruction of kidney tissue as a result of the blood vessel changes of atherosclerosis. Cholesterol and other lipids deposit along the walls of the blood vessels. This causes the walls of the blood vessel to become less elastic ("hardening of the arteries"). The lipid deposits create uneven blood flow around the deposit and may result in formation of blood clots that may cause acute renal artery occlusion or that may travel to other locations throughout the body (embolize). Atherosclerosis of the aorta can lead to showers of small emboli containing cholesterol and debris. These emboli cause death of many small areas of the kidney and thus permanent acute renal failure or chronic renal failure.

The incidence of atheroembolic renal disease is 4 out of 10,000 people. It is more common in men, especially those over 60 years old. Risk factors for atherosclerotic disorders include having a personal or family history of cerebrovascular disease, heart disease, coronary artery disease, peripheral vascular disease, diabetes mellitus, and hypertension. Smoking, obesity, and high serum lipids (such as total cholesterol and triglycerides) also greatly increase the risk of atherosclerotic disorders.

Clots or emboli may form in the kidney because of atherosclerotic deposits (plaques), or they may travel to the kidney from other locations. Risks for emboli that travel to the kidney increase with a history of thromboembolism (blood clots) in any location, especially if severe enough to require treatment with anticoagulants. Anticoagulant therapy may trigger an attack of atheroembolism. Risks of emboli are also increased with recent aortic surgery or procedures involving the blood vessels such as aortography or arteriography.

Atheroembolic renal disease may cause reduced kidney function including acute or chronic renal failure. It may cause hypertension that is refractory or difficult to control. The disorder may show no symptoms in some cases, unless acute arterial occlusion or renal failure develops. Hypertension that is difficult to control may be the first clue that atheroembolic renal disease exists, or routine examination or examination for other disorders may reveal the disease.

Prevention: Modify controllable risk factors. Lose weight if obese, decrease or stop smoking, and follow the health care provider’s recommendations to control diabetes or hypertension. Dietary reduction in fats, especially saturated fats, may help to reduce serum lipid levels.

Symptoms:

• flank pain or abdominal pain
  • abrupt onset
  • continuous, not "colicky" or spasmodic
• blood in the urine
• pain in the abdomen, legs, or thighs
• foot pain
• purple toes
• multiple spontaneous skin ulcers
• blood pressure, high

• nausea, vomiting
• loss of appetite
• weight loss
• decreased urine output (or none)
• swelling of the body--any location
• decrease in sensation
• skin pigment changes
  • increase in pigmentation (hyperpigmentation)
• dry skin, itching
• decreased alertness
  • drowsiness, confusion, lethargy

Signs and Tests: An examination may show generalized edema. Fundoscopic examination of the eyes may show particles in the small arteries of the retina. Signs of fluid overload may develop if renal failure is present, including abnormal sounds on examination with a stethoscope (auscultation) of the heart and lungs. A loud whooshing sound (bruit) may be heard on auscultation over the aorta or renal artery. The blood pressure may be elevated, and there may be a history of hypertension that is difficult to control. There may be multiple superficial ulcers of the skin of the lower feet.

These tests help diagnose the disorder:

• blood, protein, eosinophils, or other abnormality in a urinalysis
• CBC abnormal (eosinophilia, thrombocytopenia).
• low serum complement
• high lipids - serum
• Accumulation of nitrogen wastes in the blood (azotemia) if kidney failure develops:
  • BUN elevated.
  • creatinine elevated.
• increased potassium or other abnormality in serum chemistry (chem-7 or chem-20)
• A kidney or abdominal ultrasound, abdominal CT scan, abdominal MRI, or abdominal X-ray may be abnormal, indicating atheroembolic disease.
• A renal arteriography may show acute blockage (occlusion).
• An IVP may show decreased functioning of the kidney.
• A kidney biopsy or biopsy of other suspect tissue may show changes indicating atheroembolic disease.

Treatment: Treatment goals vary depending on the manifestation of the disorder (asymptomatic, hypertension, arterial occlusion, renal failure, and so on) and the severity of symptoms.

Medications may include anti-hypertensives and medications to lower serum lipid/cholesterol levels. Anticoagulant or antiplatelet medications may be used to reduce the risk of clot formation (thrombi).

Other treatments for renal failure or other manifestations may be appropriate.

Self-care is important to reduce progression of the disorder.
Dietary changes may include reduction of fats and cholesterol. Renal failure may require restriction of protein, salt, fluids, or other dietary changes. Lifestyle changes may be recommended. Stopping smoking is extremely important, increasing exercise, weight loss, and others may also help.

Prognosis: The outcome varies but is generally poor. The disorder is often chronic and progressive. Lifestyle changes may help to reduce the course of progression.

Complications:

• acute renal failure
• chronic renal failure
• hypertension
• malignant hypertension
• embolization of blood clots to other location of the body--brain, heart, lungs, and others.

Call your health care provider if urine output decreases or stops, or if blood is seen in the urine.

Call your health care provider if severe abdominal pain or leg pain develops, unexplained ulcers appear on the legs or feet, or the toes turn purple and foot pain develops.