Retroperitoneal fibrosis: symptoms, causes, diagnosis and treatment

Kidney Care UK describes retroperitoneal fibrosis as a rare condition that causes scar tissue to develop around the blood vessels and ureters, the tubes connecting the kidneys and bladder. The retroperitoneum is the area of the body behind the stomach and intestines and in front of the backbone, where the ureters run. Fibrosis is a type of internal scarring.

The UK primary care reference site Patient.info, in its professional article, describes it as a chronic inflammatory and fibrotic process in the retroperitoneum that can lead to compression of structures there, including encasement of the aorta, vena cava, ureters and the psoas muscle. Because the ureters run through this area, they are the structures most often affected, and blockage of urine flow is the main danger.

According to Kidney Care UK it affects around 1 in 100,000 people in the UK, twice as many men as women, and is usually first diagnosed around the age of 60. Patient.info’s professional article gives a similar picture, saying it most commonly affects people between 40 and 60 and that men are affected more often, in a ratio of approximately 2:1 or 3:1.

Because it is rare, the diagnosis is sometimes made late, when someone is evaluated for kidney problems or obstruction of the urinary tract.

Some people have no symptoms. For those who do, Kidney Care UK lists the following common symptoms and says they may come and go, with times when the condition becomes inactive and then flares up again later.

• pain in the abdomen, lower back or groin

• pain in the legs that is worse when walking

• swelling of one leg due to blocked blood supply

• jaundice (yellowing of the skin and the whites of the eyes)

• fevers and/or night sweats

• loss of appetite

• weight loss

• lack of energy

Kidney Care UK says the exact cause is not yet known and appears to be a variety of possible causes: an overactive immune system, use of the migraine medicine methysergide, blood vessel disease caused by an unhealthy lifestyle especially heavy smoking, exposure to asbestos, some forms of cancer, and other conditions such as vasculitis. It adds that some recent research suggests it may run in families, but the details are still being investigated.

Patient.info’s professional article says approximately 75% of cases are idiopathic, meaning no cause is found, and describes an association with IgG4-related disease. It lists identified secondary causes including some drugs, abdominal aortic aneurysm, trauma, infection, retroperitoneal malignancy and previous radiotherapy or chemotherapy. If a drug is responsible, stopping it may result in resolution of urinary tract obstruction and symptoms.

Kidney Care UK says retroperitoneal fibrosis is usually diagnosed in adults by an ultrasound scan of the kidneys, and that a CT or MRI scan may be used to give a more detailed view. Blood tests check kidney function, and a kidney biopsy may be recommended if the initial cause is unclear, although this may just show general scarring.

Patient.info’s professional article says a high index of suspicion is needed when someone has raised inflammatory markers (ESR and CRP) and kidney impairment from obstruction, that CT and MRI help define the extent and exclude secondary causes, and that biopsy remains the gold standard for diagnosis. Other conditions with similar scan appearances, such as lymphoma or other cancers, need to be excluded, which is why a biopsy is sometimes needed.

Kidney Care UK says there is no direct cure, so treatment aims to protect kidney function, reduce pain and slow down the scarring. Different treatments work for different people depending on the cause. If an overactive immune system is responsible, steroids or immunosuppressive medicines may be prescribed to dampen the immune system and reduce scarring. If it is linked to blood vessel disease, advice includes regular exercise, a healthy weight, avoiding smoking and a balanced diet.

If extensive scarring blocks the flow of urine, surgery is needed. A thin tube called a stent is inserted into the ureter to keep it open, done as a day case under general or spinal anaesthetic, and stents usually need replacing every few months because they can block. If stents are not effective, an operation called ureterolysis may be needed to free the ureter from the fibrous tissue and reduce the chance of future blockages.

Patient.info’s professional article says glucocorticoids are traditionally considered the mainstay of treatment for idiopathic disease, that rituximab has been used, that temporary drainage of the upper urinary tract can restore kidney function before surgery, and that laparoscopic ureterolysis is very effective with morbidity and efficacy comparable to open surgery.

Kidney Care UK says most people with retroperitoneal fibrosis can live normal lives with regular monitoring and that it is rare for dialysis or transplantation to be needed. Patient.info’s professional article says that symptoms often begin to improve within a few days of starting treatment, and that non-malignant disease has a generally good prognosis unless it is not appropriately diagnosed or treated, when it can cause severe complications such as end-stage kidney disease. Lifelong follow-up is required because it can progress or recur.

In practice that means periodic blood tests of kidney function, scans when your team advises, and prompt reporting of symptoms returning. Kidney Care UK says it is not aware of any UK-based support groups specifically for the condition, so your kidney or urology team and a kidney charity may be the best sources of information.

See a GP if you have persistent pain in the abdomen, lower back or groin, one swollen leg, unexplained weight loss, fevers or night sweats, or jaundice. Seek urgent help the same day if you pass much less urine than usual, cannot pass urine, or have severe loin pain with fever or vomiting, since these can point to a blocked kidney or infection.