腎臟動靜脈畸形: 罕見且潛在致命性的血尿成因

徐任廷¹、鐘旭東¹、謝尚儒¹

¹亞東紀念醫院 外科部 泌尿科

Renal arteriovenous malformation: a rare and potentially life-threatening cause of hematuria

Jen-Ting Hsu¹ , Shiu-Dong Chung¹, Shang-Ju Hsieh¹

Division of Urology¹ Department of Surgery, Far Eastern Memorial Hospital, New Taipei City

Introduction: Renal arteriovenous malformations (AVMs) are relatively rare vascular abnormality, with communications between an artery and a vein with extraneous capillary level. Renal AVMs have an estimated incidence of less than 0.04%. Renal AVMs can be distinguished into two types, congenital and acquired. Less than 25% of all AVMs, congenital AVMs result from a failed embryologic vascular developing process. Acquired AVMs with the origin of inflammation, renal surgery, secondary to trauma or percutaneous needle biopsy makes up the raise in incidence. Women are affected three times as often as men in renal AVMs, and the right kidney is involved slightly more often than the left. Although congenital, they rarely present clinically before the third or fourth decade. The main clinical feature of AVM is sudden and uncontrollable hematuria, probably leading to death at worse.

The dysplastic architecture of arteriovenous connection can be demonstrated by two categories. The cirsoid type is most typical, characterized by conglomerate of arterial branches and tortuous channels forming a nidus. The angiomatous type with a single arterial feeder interconnecting distal branches and draining veins.

Case report:  A 20-year-old female patient presented with a sudden onset of gross hematuria accompanied with dysuria. Left pressure-like flank pain was also mentioned. Physical examination showed no costovertebral angle knocking pain, rebounding tenderness or pulsatile perirenal hematoma. There was no previous history of renal trauma, renal biopsy or surgery. Urine analysis revealed hematuria and pyuria. Biochemistry test declared elevated white blood cell (21.16*10^3/μL) and mild decreased hemoglobin (11.0*g/dL). Ultrasound study revealed left mild hydronephrosis with markedly increasing blood flow in the lower pole of left kidney and huge blood clots in urinary bladder. Computed Tomography angiography (CTA) demonstrated the lower and posterior segmental branches of the left renal artery tangling with the draining vein. Ectasia of the feeding arteries and draining veins were seen in the site of renal AVM.

The merged 3D image showed one small AVM with multiple feeding arteries at the lower part of the left kidney. Angiography and embolization were performed with Seldinger`s method via right transfemoral approach with 5Fr sheath under local anesthesia. 5Fr RC1 catheter was placed into the left renal artery. Angiography revealed the left renal arteriovenous malformation with numerous tiny serpiginous vessels and contrast agent returned rapidly into the renal vein before parenchymal phase. An ASAHI microcatheter passed through and placed into the targeted AVM feeding artery. Embolization was performed with a slow injection of glue to embolize the nidus. Disappeared malformation was noted on renal angiography after the trans-arterial embolization (TAE). Following the embolization, no significant post-embolization syndrome (fever, pain, nausea and vomiting) was noted. Transurethral removal of bladder blood clots and cystoscopy exam were performed on the next day. No more gross hematuria was noticed. Under stable clinical condition, she was discharged smoothly.