Patient will present as → a 69-year-old man with a 55-pack-year smoking history, diabetes type II, and hyperlipidemia presents to his primary care clinic for an annual exam. He has no complaints. He reports that his blood glucose has been under tight control and that he has not smoked a cigarette for the past 5 months. Vital signs are HR 69 bpm, BP 180/100 mmHg, RR 12/min, and O2 saturation 99% on room air. Physical examination is notable for bruits bilaterally, just lateral of midline near his umbilicus. You initiate an anti-hypertensive medication, but his blood pressure continues to be suboptimal. Creatinine is 3.5.
Renal artery bruit (with bowel sounds)
Renal artery stenosis is the narrowing of one or both renal arteries, most often caused by atherosclerosis or fibromuscular dysplasia.
- This narrowing of the renal artery can impede blood flow to the target kidney, resulting in renovascular hypertension – a secondary type of high blood pressure.
May hear a renal artery bruit on auscultation
- Patients may present with HTN before age 30, HTN with CAD or PVD history, Hypertension resistant to three or more drugs
- If a patient is placed on an ACE inhibitor and suddenly develops acute renal failure or a sharp rise in BUN/CR, you should think of renal artery stenosis
Ultrasound is often initial imaging in those < 60 years of age with suspected RAS
- Renal arteriography is the GOLD STANDARD for diagnosis
Renal arteriography demonstrating renal artery stenosis
Stenting of renal arteries
- Treatment is with percutaneous transluminal angioplasty (PTA) plus stent placement or with surgical bypass of the stenotic segment
- Usually, an extensively infarcted kidney must be removed if revascularization is not expected to result in functional recovery
- In patients with renal artery stenosis, especially those with stable renal function, the most appropriate initial management is medical management with antihypertensive medications
- ACE inhibitors and ARBs can be used in unilateral and, if glomerular filtration rate (GFR) is monitored closely, in bilateral renal artery stenosis
- Additional antihypertensive medications are frequently required
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Question 1 |
A 55-year-old man with a history of smoking and hyperlipidemia presents with sudden onset of severe hypertension and a decrease in renal function. He also reports episodic flank pain. Which of the following is the most likely diagnosis?
Acute glomerulonephritis Hint: Usually presents with hematuria, proteinuria, and sometimes hypertension, but not typically with sudden severe hypertension. | |
Renal artery stenosis | |
Chronic kidney disease Hint: Develops gradually and is not typically associated with sudden severe hypertension. | |
Renal cell carcinoma Hint: Can cause flank pain and hematuria, but sudden severe hypertension is less common. | |
Pyelonephritis Hint: Presents with fever, flank pain, and urinary symptoms, not typically with severe hypertension. |
Question 1 Explanation:
Renal artery stenosis, often caused by atherosclerosis, particularly in patients with risk factors like smoking and hyperlipidemia, can lead to secondary hypertension and a decrease in renal function. The sudden onset of severe hypertension and episodic flank pain, along with a decrease in renal function, is characteristic of renal artery stenosis.
Question 2 |
A 62-year-old woman with uncontrolled hypertension despite multiple antihypertensive medications undergoes evaluation for secondary causes. On physical examination, a bruit is heard over the right upper quadrant of the abdomen. What is the most appropriate diagnostic test to confirm the suspected diagnosis of renal artery stenosis?
Renal ultrasound with Doppler Hint: Useful but less sensitive than CT angiography for detecting renal artery stenosis. | |
CT angiography of the renal arteries
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Magnetic resonance angiography (MRA) of the renal arteries Hint: An alternative to CT angiography but may be less available or contraindicated in some patients. | |
Renal biopsy Hint: Not indicated in the initial evaluation of renal artery stenosis. | |
24-hour urine collection for metanephrines Hint: Used to diagnose pheochromocytoma, not renal artery stenosis. |
Question 2 Explanation:
CT angiography of the renal arteries is an appropriate diagnostic test for suspected renal artery stenosis, especially in a patient with uncontrolled hypertension and an abdominal bruit. It provides detailed images of the renal vasculature and can identify narrowing or blockage of the renal arteries.
Question 3 |
A 70-year-old man is diagnosed with renal artery stenosis after presenting with difficult-to-control hypertension and an abdominal bruit. His renal function is stable. What is the most appropriate initial management for this patient?
Medical management with antihypertensive medications | |
Immediate surgical revascularization Hint: Considered in cases with refractory hypertension or deteriorating renal function. | |
Percutaneous transluminal renal angioplasty with stenting Hint: An option for certain patients, particularly those with fibromuscular dysplasia or those who fail medical therapy. | |
Chronic dialysis Hint: Indicated in end-stage renal disease, not as initial management for renal artery stenosis. | |
Nephrectomy Hint: Not a treatment for renal artery stenosis. |
Question 3 Explanation:
In patients with renal artery stenosis, especially those with stable renal function, the most appropriate initial management is medical management with antihypertensive medications. This approach aims to control blood pressure and prevent further renal damage. Angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) can be used in unilateral and, if glomerular filtration rate (GFR) is monitored closely, in bilateral renal artery stenosis. These medications can potentially reduce GFR and increase serum blood urea nitrogen and creatinine levels. Additional antihypertensive medications are frequently required.
Question 4 |
A 51-year-old man with diagnosed renal artery stenosis presents with elevated BUN and creatinine levels and has recently been diagnosed with hypertension. Which antihypertensive medication should be avoided in this patient?
Hydrochlorothiazide-Triamterene | |
Prazosin Hint: An alpha-blocker like prazosin is generally safe in renal artery stenosis and does not directly worsen renal function. | |
Nifedipine Hint: This calcium channel blocker is often used to manage hypertension and does not have a direct deleterious effect on renal artery stenosis. | |
Verapamil Hint: Another calcium channel blocker, verapamil is typically safe in patients with renal artery stenosis. | |
Furosemide Hint: While loop diuretics like furosemide can be used cautiously in renal artery stenosis, they are not contraindicated as thiazide diuretics are. |
Question 4 Explanation:
Hydrochlorothiazide-Triamterene, a combination of a thiazide diuretic and a potassium-sparing diuretic, should be avoided in patients with renal artery stenosis. Thiazide diuretics can further reduce renal perfusion in the setting of renal artery stenosis, potentially worsening renal function. Although we did not include Angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) in the answer choices they can be used in unilateral and, if glomerular filtration rate (GFR) is monitored closely, in bilateral renal artery stenosis.
There are 4 questions to complete.
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References: Merck Manual · UpToDate