Unusual Clinical Presentation of Nutcracker Phenomenon.

Dear Editor, A 34-year-old female presented with progressively worsening left flank pain. The pain was initially relieved by analgesics but subsequently increased in severity and frequency. There were no complaints of haematuria, dysmenorrhoea or dyspareunia. Physical examination was essentially unremarkable with no palpable abdominal mass or pelvic varicose veins. Urinalysis suggested mild urinary tract infection. Ultrasonography revealed mild left-sided hydronephrosis. This was further evaluated with computed tomography (CT) which demonstrated a vascular aneurysm compressing upon the left pelvi-ureteric junction (PUJ) (Fig. 1A). The initial impression was that of a large left renal artery aneurysm. Catheter angiogram was performed with a view to treat the vascular lesion via endovascular approach. Diagnostic angiogram demonstrated no arterial abnormality. A renal venogram was acquired. It showed a venous aneurysm arising from the left renal vein (LRV), causing compression upon the left PUJ (Fig. 1B). The pressure gradient between the LRV and inferior vena cava measured approximately 5 mmHg, clinching the diagnosis of nutcracker syndrome (NCS). LRV hypertension is defined as a gradient equal or greater than 3.0 mm Hg.1,2 However, in advanced cases where collateral circulation has formed, the pressure gradient may be normal. The increase in venous pressure within the LRV is believed to be the cause of the large venous aneurysm. The decision was made to proceed with endovascular treatment of the venous aneurysm. “Jailing” technique was used with stent-assisted coil embolisation of the venous aneurysm. At the same time, overlapping stents were deployed into the LRV. Longer stents were not available locally and hence 2 overlapping stents were used. Posttreatment venogram showed complete occlusion of the venous aneurysm (Fig. 1C). The patient was discharged well 2 days later and remained asymtomatic after 6 months of follow-up.