Can Complex Kidney Cyst Cause Back Pain and Blood Urine

Q: I have done a MRI that suspects there is a complex cyst in the extreme upper pole of the left kidney. Recently, I have terrible back pain and blood in my urine. I am wondering whether complex kidney cyst could cause back pain and blood urine.

A: Complex kidney cyst indeed can cause back pain and blood urine. Different from simple kidney cyst, complex cyst has irregular cyst lining, shape and internal structure. The internal walls in complex cyst can divide it into many parts. Just because of these irregular walls, complex cyst has a high risk of developing kidney cancer.

A complex cyst is filled with fluid, but it may also have tissues inside of it. These tissues, called enhancements, mean that part of complex kidney cyst gets a blood supply. As more and more fluid fills in cyst, the growing cyst, sometimes larger than the kidney itself, is more likely to stretches its wall and put pressure on kidney or other organs. In this condition, back pain occurs easily.

At the same time, an enlarged cyst present on the surface of the kidney might be pressed by the surrounding tissues, leading to burst. Then, a ruptured cyst can cause severe back pain, blood urine or even sepsis. If left untreated timely, a life-threatening situation might arise.