Tuberculous pseudoaneurysm of the renal artery: A rare manifestation of extra-pulmonary tuberculosis

Abstract

Mycotic pseudoaneurysms are rare dilations of the arterial wall caused by infection. We present a case of a 62-year old man with disseminated tuberculosis and a large mycotic pseudoaneurysm involving the main renal artery and vein. Despite being on appropriate rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE) therapy, the pseudoaneurysm grew with increasing concern for potential rupture. The patient subsequently underwent an open right simple nephrectomy with resection of the pseudoaneurysm, partial resection of the inferior vena cava, and reconstruction.

1 Introduction

Pseudoaneurysms are rare and occur as a sequela of vessel wall destruction leading to weakening of the vessel and subsequent dilation. Unlike true aneurysms which are contained by all three layers of the arterial wall, a pseudoaneurysm is a locally contained hematoma that does not contain any layers of the arterial wall, bounded instead by products of the clotting cascade. While pseudoaneurysms are most commonly due to iatrogenic causes following endovascular procedures and vascular anastomotic complications, they can also be caused by trauma, infection, or inflammatory processes.

Infectious pseudoaneurysms are a rare entity. Also known as “mycotic pseudoaneurysms”, they occur predominantly by hematogenous spread from bacterial or fungal infections. The most commonly involved arteries of mycotic pseudoaneurysms are the aorta, femoral, splanchnic, and cerebral arteries. Mycotic aneurysms of the renal artery are rare, with only 20 cases reported in the literature that occurred following renal transplantation due to Candida species. Mycotic aneurysms of the renal artery due to tuberculosis infection, or tuberculous pseudoaneurysm of the renal artery, are even rarer, with only one known prior case report published in 1976.

We describe a case of a 62-year old man with disseminated tuberculosis complicated by Pott’s Disease of T12-L1 with spinal epidural abscess and a large tuberculous pseudoaneurysm of the right renal artery involving the right renal hilum. The patient subsequently underwent an open right nephrectomy with en-bloc resection of the pseudoaneurysm, partial resection of the inferior vena cava (IVC), and reconstruction with the surgical technique detailed in this report.

2 Case presentation

A 62-year old male with limited access to routine health care presented to an ambulatory urgent care clinic for severe back pain and bilateral lower extremity weakness. Evaluation was notable for a creatinine of 3.7 mg/dl (unknown baseline) and a Computed Tomography (CT) chest demonstrated spiculated lung nodules with diffuse bilateral pulmonary micronodules in a miliary distribution suggestive of tuberculosis. Abdominal imaging demonstrated a 4 cm thoracic spinal abscess with significant osseous destruction of the lower thoracic spine. In addition, imaging revealed moderate left hydroureteronephrosis with a thickened bladder wall and a non-specific 7.4 cm right hilar mass with an atrophic right kidney. An MRI abdomen was obtained which demonstrated a large vascular lesion in the right renal hilum consistent with a pseudoaneurysm. A Lasix washout renogram subsequently showed a differential function of 6 % right kidney. Urine and sputum cultures demonstrated acid-fast bacilli (AFB), confirming the diagnosis of disseminated tuberculosis.

Patient subsequently underwent an urgent T11/12 laminectomy and a left percutaneous nephrostomy tube placement for renal decompression and preservation. Endovascular management of the pseudoaneurysm was not recommended due to infectious etiology, as well as the large size of the pseudoaneurysm near the great vessels. After an extensive discussion about management options and shared decision-making, the deconditioned patient proceeded with medical management of disseminated tuberculosis prior to consideration for surgical intervention for mycotic pseudoaneurysm. Rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE) therapy was initiated, and the patient was discharged home with plan for repeat imaging to evaluate pseudoaneurysm after completion of treatment.

However, the patient re-presented back to the emergency room two weeks later with generalized weakness. Repeat cross-sectional imaging demonstrated an enlarging pseudoaneurysm of the right renal artery now measuring 8.4 cm ( Fig. 1 ). Given the concern for potential rupture of expanding pseudoaneurysm in a non-functioning kidney despite RIPE therapy, the decision was made to proceed with open nephrectomy and resection of mycotic pseudoaneurysm.

2.1 Surgical management

The patient underwent an open right simple nephrectomy with resection of the right renal artery pseudoaneurysm, and partial resection of the IVC. The patient was positioned supine and a midline incision was created just below the xiphoid process to 2 cm below the umbilicus. The Omni retractor was used to retract the body walls. An incision was made near the white line of Toldt and the right colon was reflected medially. The duodenum was noted to be adherent to the pseudoaneurysm capsule and required meticulous sharp dissection to kocherize the duodenum. The inferior vena cava was exposed and the pseudoaneurysm was identified. This was noted to also be adherent to the inferior vena cava at the level of the renal vein ostium. A split-and-roll technique was used expose the vena cava cephalad and caudad to the aneurysm and the lumbar veins were clipped and divided. The right gonadal vein was ligated with a 2-0 silk tie and transected at its origin. The interaortocaval region was dissected to identify the right renal artery at its origin from the aorta and suture-ligated with two 0-silk ties proximal to the pseudoaneurysm.

Attention was then turned to the hilar pseudoaneurysm which extended medially and involved the posterior portion of the IVC. Proximal and distal control of the IVC was achieved using Rummel tourniquets and umbilical tape. The pseudoaneurysm was then meticulously dissected and freed from the posterior vena cava. The Ligasure device was used to mobilize the kidney superiorly, laterally, and posteriorly. The right adrenal gland was spared. The right ureter was clipped and divided. Once the kidney and pseudoaneurysm were completely mobilized, the Rummel clamps were tightened and a 15# blade was used to transect the right renal vein at the end of its ostia. The specimen was then removed from the field and sent for permanent pathology ( Fig. 2 ).