Renal Vein Thrombosis

Renal vein thrombosis is the occlusion of one or both renal veins. It may present with either chronic bilateral thrombosis or, less often, with acute unilateral or bilateral thrombosis. May be associated with other thrombo-embolism, including pulmonary embolism.

• Renal vein thrombosis is probably under-diagnosed. The overall prevalence is unknown.
• Nephrotic syndrome is the most common cause. Other causes include renal cancer, renal transplantation, Behcet's disease, hypercoagulable states and antiphospholipid syndrome.¹
• Rare in children and usually due to severe illness, e.g. asphyxia, severe infection, dehydration.

Presentation may be difficult to differentiate from those of the underlying condition, e.g. nephrotic syndrome or renal malignancy.

• Acute: loin pain, decline in renal function, haematuria, renal enlargement, asymmetrical leg oedema, increased proteinuria in nephrotic syndrome.
• Chronic: may be no symptoms or signs and detected by decline in renal function, increase in proteinuria or seen on abdominal MRI scan.
• Other features of both acute and chronic forms are pulmonary emboli, increased peripheral oedema, dilated abdominal veins, left varicocele if left renal vein is thrombosed.

Should be considered as a possible cause of:

• Increased proteinuria or decline in renal function in patients with nephrotic syndrome.
• Pulmonary emboli with no lower limb deep vein thrombosis.

• Serum creatinine and urinary protein (unexplained decline in renal function or sudden increase in proteinuria). Other laboratory investigations will be dependent on clinical situation, e.g. for nephrotic syndrome or hypercoagulation.
• Doppler ultrasound.
• IVP findings are rarely specific but may show an enlarged kidney. If the renal pelvis is observed, it is usually distorted. A characteristic but uncommon finding is notching of the ureter, caused by tortuous collateral veins near the ureters.
• Inferior vena cavography can be diagnostic but otherwise will need selective renal vein catheterisation can be performed.
• Renal arteriography may be useful in cases of renal trauma or tumour, when renal artery involvement is common.
• Renal ultrasound: ultrasound is usually not sensitive enough to assist in making the diagnosis.
• CT scan or MRI: currently the procedures of choice for non-invasive diagnosis. May also help detect the presence of tumour.
• Renal biopsy: essential in evaluating patients with nephrotic syndrome.

• Glomerulonephritis, especially if causes nephrotic syndrome: most commonly membranous glomerulonephritis,² but may also be associated with membranoproliferative, minimal change or rapidly progressive glomerulonephritis. Also SLE and amyloidosis.
• Renal cell carcinoma: by extrinsic pressure on renal vein or invasion of renal vein or inferior vena cava. May also be due to extrinsic compression by any other tumour or retroperitoneal mass.
• Trauma
• Dehydration, especially in infants
• Hypercoagulable states
• May be associated with thrombocytopenia
• Post-renal transplantation

• Anticoagulation with warfarin. If renal vein thrombosis is associated with pulmonary emboli, anticoagulation should be continued for as long as nephrotic syndrome persists.
• Streptokinase may be used to lyse acute thrombosis.
• Diuretics and ACE inhibitors or angiotensin II receptor blockers decrease proteinuria from nephrotic syndrome.³ Decreasing protein loss in the urine decreases hypercoagulability.
• Treatment of any underlying associated disease.

Surgical¹

• Surgical treatment is rarely required.
• Inferior vena caval filters may be used in bilateral renal vein thrombosis.
• Surgery may be necessary for renal vein thrombosis caused by renal cell cancer.

• Recurrent thrombo-embolism, e.g. stroke
• Acute renal failure
• Complications specific to the underlying cause, e.g. graft failure after renal transplantation

• Prognosis is determined by the effects on nephrotic syndrome, renal dysfunction or the complications resulting from thromboembolism.
• Prognosis of any underlying cause is worsened by the onset of acute renal vein thrombosis.
• Adversely affects graft survival after renal transplantation.

Prophylactic subcutaneous heparin for those with any condition that potentially predisposes to renal vein thrombosis.