A disease of the kidneys caused by narrowing of the kidney blood vessels and/or blood clots that form in the renal artery as a complication of atherosclerosis (see also renal artery stenosis ).

Alternative Names

Renal disease - atheroembolic; Cholesterol embolization syndrome; Atheroemboli - renal; Atherosclerotic disease - renal

Causes, incidence, and risk factors

Atheroembolic renal disease is damage and destruction of kidney tissue due to atherosclerosis of the blood vessels that supply blood to the kidneys. Atherosclerosis occurs when cholesterol and other fats ( lipids ) deposit along the walls of the blood vessels. This causes the walls of the blood vessel to become less elastic, called " hardening of the arteries ." The lipid deposits cause blood to flow unevenly, and this can result in the formation of blood clots that may cause partial or complete blockage of the blood vessel, or acute renal artery occlusion . The clots can also travel to other parts of the body and damage other organs. This is known as embolization. Atherosclerosis of the aorta can lead to showers of small emboli containing cholesterol and debris. These emboli, if they travel to arteries that supply the kidneys, cause damage to, and death of, many small areas of the kidney. A permanent complication of this is 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 due to atherosclerotic deposits, called plaques, or they may travel to the kidney from other locations. If you have previously had an episode of thromboembolism, or blood clots, elsewhere, the risk of having emboli that travel to the kidney increases. This is especially true if the previous episode was severe enough to require treatment with anticoagulants. Anticoagulant therapy may itself trigger an embolism. The risk of emboli is 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 also result in hypertension that is difficult to control. Sometimes the person will have no symptoms, unless acute arterial occlusion or renal failure develops. Hypertension, or high blood pressure, 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.

Signs and tests

An examination may show edema , or swelling, of the whole body. Fundoscopic examination of the eyes may show particles in the small arteries of the retina . Evidence 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, called a 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. Medical dyes or special techniques may be used to enhance the images and improve diagnosis, such as in magnetic resonance angiography.

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 what the doctor finds ( asymptomatic , hypertension , arterial occlusion , renal failure ) and the severity of symptoms. Medicines may include anti-hypertensives to treat high blood pressure and medicines to lower serum lipid/ cholesterol levels . Anticoagulant or antiplatelet medications may be used to reduce the risk of clot formation ( thrombi ). Sometimes surgery is necessary to unblock the artery, or bypass it. Sometimes it is also necessary to remove the damaged kidney. Other treatments for renal failure or other complications may be appropriate. Taking care of yourself is important to reduce progression of the disorder. You may need to reduce fats and cholesterol in your diet. If you have renal failure, you may need to restrict protein , salt, and fluids, or make other dietary changes. Your doctor may also recommend other lifestyle changes. Stopping smoking is extremely important, increasing exercise , weight loss , and a variety of other things may also help.

Expectations (prognosis)

The outcome varies but is generally poor. The disorder is often long-term, or chronic , and progressive. Lifestyle changes may help slow progression of the disease.

Complications

Acute renal failure

Chronic renal failure

Hypertension

Malignant hypertension

Damage to the healthy kidney from high blood pressure

Embolization of

blood clots to other location of the body -- brain, heart, lungs, and others

Calling your health care provider

Call your doctor if urine output decreases or stops, or if blood is seen in the urine. Call your doctor if you have severe abdominal pain or leg pain , unexplained ulcers appear on your legs or feet, or your toes turn purple and you get foot pain .

Prevention

You can alter the factors that increase the risk of getting atheroembolic renal disease. You should lose weight if you are obese , decrease or stop smoking , and follow the your doctor's recommendations to control diabetes or hypertension . Reducing fats , especially saturated fats, in your diet may help to reduce serum lipid levels.