Recurrent urinary retention due to clots caused by a congenital renal arteriovenous malformation that forms a complex vascular network: Report of two cases

Abstract

Introduction Repeated urinary retention due to clots caused by congenital renal arteriovenous malformation is rare. Case presentation A 40‐year‐old woman (case 1) and a 66‐year‐old man (case 2) experienced recurrent urinary retention due to clots. Neither patient had a history of renal trauma nor was taking any medications. Contrast‐enhanced abdominal computed tomography revealed a large hematoma in the renal pelvis and ureter with no masses, stones, or vascular lesions and only dilated blood vessels in the arterial phase in case 1. Angiography of the kidney in both patients revealed an arteriovenous malformation, and embolization of the arteries feeding the arteriovenous malformation was performed. Soon after embolization, hematuria disappeared completely with no recurrence for 5 years in case 1 and 2 years in case 2. Conclusion Congenital renal arteriovenous malformation should be considered as a cause of recurrent clot retention, and angiographic embolization of the feeding arteries can be an effective treatment.

Acute Abdominal Pain Without Gross Hematuria as an Atypical Initial Presentation of Renal Arteriovenous Malformation

“…Although physicians can easily suspect clot retention as a cause of acute abdominal pain if patients, even young patients, have recurrent gross hematuria, it is challenging to consider the possibility, especially in young patients with no episode of gross hematuria. Cases of repeated clot retention and life-threatening rupture of renal AVMs have been reported [ 5 , 6 ]. Thus, even in the first episode of clot retention, early diagnosis of renal AVMs would be desirable.…”

“…Type III renal AVMs lack capillaries; instead, arteries and veins form shunts through abnormal vessels, creating an atypical vascular network without aneurysm formation. Clinicians should be aware of the potential difficulty in diagnosing renal AVMs using contrast-enhanced CT alone [ 5 ]. It is important to recognize that if a young patient presents with gross hematuria and the cause remains unclear after contrast-enhanced CT, renal artery angiography - the gold standard for diagnosis - may be considered to confirm a renal AVM.…”