History and Physical Examination
Gross hematuria is the initial sign or symptom in most (as many as 75%) patients with a renal arteriovenous malformation (AVM).
Renal colic may result from obstructing blood clots, which may be voided as vermiform (wormlike) masses.
Rarely, during the evaluation of asymptomatic microscopic hematuria, an AVM is found and presumed to be the cause of hematuria.
A significant percentage of patients with renal AVMs are hypertensive. Half the patients with acquired AVMs and a quarter of the patients with congenital renal AVMs have high blood pressure. Preexisting hypertension is thought to be a risk factor for developing a fistula after a renal biopsy. Conversely, hypertension that develops after a biopsy can be due to increased renin secretion that is caused by relative hypoperfusion distal to the AVM.
Cardiomegaly, congestive heart failure (CHF), or both also may be present among patients evaluated for renal AVMs.
Rarely, a patient may present with hypotension from hemorrhage caused by an AVM. This has been described in numerous settings, including during pregnancy.
Occasionally, renal AVMs may mimic renal cell carcinoma and may only be identified on surgical pathology.
In rare cases, back pain has been associated with an AVM. [8]
AVMs have also been found to worsen kidney function in patients with chronic kidney disease. [9]
A history of a previous renal biopsy or percutaneous renal surgery is an important risk factor for the development of an acquired arteriovenous fistula (AVF). A history of renal trauma, especially a penetrating injury, is also an important risk factor for developing a renal AVF.
A physical evaluation may demonstrate findings of a flank bruit. A palpable mass is usually present in those patients with renal tumors as the cause of the fistula.
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Arteriogram demonstrating large right renal arteriovenous malformation with early filling of the vena cava.
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MRA reconstruction of the same patient.
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Transaxial image demonstrating large intrarenal arteriovenous malformation with enlarged renal vein.
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CT angiographic axial image showing a likely congenital renal arteriovenous malformation (AVM) in a middle-aged woman associated with aneurysmal dilation of the left renal vein. The patient presented with an episode of syncope and mild left flank pain.
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Same patient as in the previous image; CT angiogram on coronal image illustrating a prominent left arteriovenous malformation (AVM) with aneurysmal renal vein.
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CT coronal reconstruction after intrarenal angiogram demonstrating 2 large renal artery aneurysms arising from the right renal artery division at the hilum, with an associated lower pole arteriovenous fistula. This was determined to be unreasonable for embolization or coiling. This patient was asymptomatic and was imaged after a trauma.
