Acute arterial occlusion - kidney

Causes

The kidneys are very sensitive to the amount of blood that flows to them. The main artery that supplies blood to the kidney is called the renal artery. Any reduction of blood flow through the renal artery can impair kidney function. If it continues, a complete blockage of blood flow to the kidney often results in permanent kidney failure.

Acute arterial occlusion of the renal artery can occur after injury or trauma to the abdomen, side, or back. Blood clots that travel through the bloodstream (emboli) can lodge in the renal artery.

The risk of renal artery blockages increases in people who have certain heart disorders, such as mitral stenosis or atrial fibrillation, which make them likely to form blood clots.

A narrowing of the renal artery, called renal artery stenosis, increases the risk of a sudden blockage because a clot forms in the narrowed artery.

Symptoms

When one kidney does not function, you may not have symptoms because the second kidney can filter the blood.

If the other kidney is not fully functioning, blockage of the renal artery may cause symptoms of acute kidney failure. Other symptoms of acute arterial occlusion of the renal artery include:

• Abdominal pain
• Abrupt decrease in urine output
• Back pain
• Blood in the urine
• Flank pain or pain in the side

Note: There may be no pain. Pain, if it is present, usually develops suddenly.

Exams and Tests

The doctor will likely not be able to identify the problem by simply examining you, unless you have had the disorder long enough to cause kidney failure.

Tests include:

• Duplex Doppler ultrasound exam of the renal arteries to test blood flow
• MRI of the kidney arteries, which can show a lack of blood flow to the affected kidney
• Renal arteriography shows the exact location of the blockage
• Renal scan shows a lack of blood flow to the affected kidney
• Ultrasound of the kidney to check kidney size

Treatment

Often, patients do not need treatment. Blood clots may get better on their own over time.

If the blockage is discovered within a few hours, or if the affected kidney is the only working kidney, attempts may be made to open the artery.

Attempts to open the artery may include the use of clot-dissolving medications (thrombolytics) and medications that prevent the blood from clotting (anticoagulants), such as warfarin (Coumadin).

Some people may need to have the renal artery surgically repaired. Or, they may have the blockage removed with a tube called a catheter inserted into the artery.

Treatment for acute kidney failure, such as temporary dialysis, may be needed.

Outlook (Prognosis)

Damage caused by arterial occlusion may be temporary, but it is usually permanent.

If only one kidney is affected, the healthy kidney may take over filtering the blood and producing urine. In cases where there is only one working kidney, arterial occlusion leads to acute kidney failure that often becomes chronic kidney failure.

Possible Complications

• Acute kidney failure
• Chronic kidney disease
• High blood pressure
• Malignant hypertension

When to Contact a Medical Professional

Call your health care provider if you stop producing urine, or if you feel sudden, severe pain in the back, flank, or abdomen.

If you have only one functional kidney and you have symptoms of acute arterial occlusion, go to the emergency room or call the local emergency number, such as 911.

Prevention

In many cases the disorder is not preventable. The most important way to reduce your risk is to stop smoking.

Preventive use of anticoagulants may be recommended for people with a high risk of developing emboli, such as those with mitral stenosis, atrial fibrillation, or blood clotting disorders. Controlling diseases related to atherosclerosis (hardening of the arteries) may reduce your risk.

Alternative Names

Acute renal arterial thrombosis; Renal artery embolism; Acute renal artery occlusion; Embolism - renal artery

References

DuBose TD Jr, Santos RM. Vascular disorders of the kidney. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 126.

Kanso AA, Hassan NMA, Badr KF. Microvascular and macrovascular diseases of the kidney. In: Brenner BM, ed. Brenner and Rector's The Kidney. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 32.

Update Date: 6/8/2011

Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Herbert Y Lin, MD, PhD, Nephrologist, Massachusetts General Hospital; Associate Professor of Medicine, Harvard Medical School. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.