Renal Vein Thrombosis

Eyes Open to Renal Vein Thrombosis

What is Renal Vein Thrombosis?

Renal vein thrombosis is a blood clot that occurs in the veins draining blood from the kidneys. A blood clot in the renal vein will impact kidney function because it slows the flow of blood from the kidney and can reduce the kidneys’ ability to do the work of cleaning and filtering the blood. This can cause pain as well as affecting kidney function.

Renal vein thrombosis is treated with a therapeutic dose of anticoagulation. Renal function must be checked prior to starting treatment to ensure the correct anticoagulant drug and dose is used at diagnosis to allow the clot to resolve, maintain kidney function and reduce pain.

Men are twice as likely to suffer from renal vein thrombosis than women, although the reasons for this are largely unknown. It is more common in people over the age of 40.

Signs and Symptoms

Symptoms of renal vein thrombosis can include:

  • Blood clot in the lung
  • Bloody urine
  • Decreased urine output
  • Flank pain or low back pain


In adults, the most common cause of renal vein thrombosis is nephrotic syndrome, which is when the kidney becomes very leaky due to an underlying disease such as lupus. Additional causes include: 

  • Abdominal aortic aneurysm
  • Hypercoagulable state (clotting disorders)
  • Dehydration (mostly in infants)
  • Estrogen use
  • Nephrotic syndrome
  • Pregnancy and immediately after delivery
  • Trauma to the back or abdomen
  • Tumor

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