History: Individuals may complain of headache, anxiety, the sensation of the heart pounding (palpitations), a rapid heartbeat (tachycardia), light-headedness, and mental sluggishness. If the onset is acute, the individual may have abdominal or flank pain, nausea, vomiting, or fever or severe headache. Alternately, the individual may report few or no symptoms.
Physical exam: High blood pressure (hypertension) may be the only indication of renovascular hypertension. Changes in the retina (hypertensive retinopathy) may be seen. An abnormal sound may be heard when listening to the abdomen with a stethoscope (abdominal bruit). There may be evidence of heart failure such as swollen legs (peripheral edema), crackles or wheezing on listening to the lungs (rales) and an enlarged liver.
Tests: Several diagnostic procedures are used to test for renovascular hypertension. The diagnostic challenge is to find evidence of both renal stenosis and renal ischemia. Blood tests can demonstrate impaired renal function. These tests include BUN, creatinine, potassium, and plasma renin activity. Urinalysis may show blood or protein in the urine.
The captopril test involves the injection of captopril, followed by measurement of renin in the blood. Individuals with renovascular hypertension will show a rise in renin, while those with hypertension unrelated to renovascular disease (essential hypertension) will not. This test has a high percentage of false-positive results, particularly among blacks.
Radioisotope renography involves the injection of a radioisotope followed by an imaging procedure to monitor the movement of the radioisotope through the kidney. This procedure can provide information regarding the size of the kidneys, the glomerular filtration rate (GFR), and blood flow. A variation of this procedure is called captopril renography. The procedure is done before and again after injection of captopril. In renovascular hypertension, the test demonstrates a reduction in renal function. As in the captopril test, this test is less accurate in blacks.
Renal vein renin determination measures blood levels of renin in the right and left renal veins. These levels are then compared with that of the inferior vena cava. Increased renin levels indicate that the cause of the hypertension is kidney-related.
Duplex Doppler scanning utilizes ultrasound to measure the speed of blood flow through the kidney. Other procedures that allow imaging of the kidney include magnetic resonance angiography (MRA) following injection of a dye into the renal arteries, and spiral computed tomography (CT) following injection of a contrast agent.
Conventional renal arteriography and using digital imaging which allows subtraction of bone and soft tissue and the use of less dye (intra-arterial digital subtraction angiography) are reserved for individuals who are high-risk for renovascular hypertension. This is because the procedure is invasive. The procedure takes place in the hospital on an outpatient basis. A catheter is inserted into the renal artery. A dye is then injected through the catheter into the artery. X-ray pictures are taken as the dye circulates throughout the kidney.
Source: Medical Disability Advisor