Idiopathic retroperitoneal fibrosis

by | Gastrointestinal Health

idiopathic retroperitoneal fibrosis

What is idiopathic retroperitoneal fibrosis 

Idiopathic retroperitoneal fibrosis is also known as primary retroperitoneal fibrosis.

 Idiopathic retroperitoneal fibrosis (IRF) is a rare disease causing inflammation and fibrosis (scarring) around the abdominal aorta (largest artery from the heart) and the iliac arteries (abdominal aorta splits into two large arteries). 1  2  3 

The inflammation spreads into the retroperitoneum, which is the space behind the abdomen. This inflammation can cause fibrosis of the ureters and kidney damage. It is difficult for the urine to pass through the partially blocked ureters to the kidneys and bladder.  2  3  4

Retroperitoneum contains the kidneys, adrenal glands, pancreas, lymph nodes, nerve roots, abdominal aorta and inferior vena cava.

Fibrosis – fibrous tissue as a side effect of healing from injury or inflammation.

 Peritoneal cavitythe peritoneum is the membrane that lines the abdominal wall and covers most of the organs in the abdomen such as the intestines.


Idiopathic retroperitoneal fibrosis has different symptoms at each stage of the condition.

Early stages include:

  • dull to intense pain (abdominal, back or side);
  • excessive thirst; and
  • leg discoloration with oedema (swelling). 2 

 Later stages include:

  • intense to severe pain (abdominal, testicular, back or side);
  • fatigue;
  • psoriasis (red and itchy skin);
  • nausea;
  • appetite loss;
  • vomiting;
  • pale skin;
  • weight reduction;
  • fever;
  • difficulty urinating;
  • haematuria (blood in urine); and
  • impaired limb movement. 2  3   4


Idiopathic retroperitoneal fibrosis has no definite cause.  2  3

Some possible causes include:

  • small-vessel vasculitis (inflammation/narrowing of the vessels);
  • organ-specific autoimmune diseases (immune system lowers or increases in activity);
  • environmental (diet, diabetes or pollution); and
  • genetic factors.  4

Idiopathic retroperitoneal fibrosis is secondary when it results from other conditions. 

Some identifying factors include:

  • renal failure;
  • malignancies;
  • infections;
  • injuries;
  • drugs;
  • radiotherapy; and
  • surgery. 1  3  

More than 75 percent of idiopathic retroperitoneal fibrosis cases are diagnosed as idiopathic retroperitoneal fibrosis. It is more common in men than women. 3   4

Risks and complications

Idiopathic retroperitoneal fibrosis mainly affects the aorta and iliac arteries. It can worsen or cause new onset of hypertension (high blood pressure) in one-third of those diagnosed.  6

Hypertension and inflammation of the main blood vessels can reduce blood flow through the thoracic (chest) aorta and has been associated with ischaemic stroke. 7

Idiopathic retroperitoneal fibrosis can also cause obstruction of the mesenteric arteries (vessels taking blood from the aorta to the intestines) and inferior vena cava (vessel taking blood back to the heart) with soft tissue growth increasing the risk of multiple organ failure.  6

When it progresses to a secondary condition with idiopathic retroperitoneal fibrosis there is risk of a benign tumour becoming malignant and spreading to parts of the brain or the spinal cord.  3

Tests and diagnosis

Idiopathic retroperitoneal fibrosis can best be diagnosed by assessing computed tomography (CT), magnetic resonance imaging (MRI) and/or positron emission tomography (PET).  7

Idiopathic retroperitoneal fibrosis assessment can include:

  • CT/angiography scan for soft tissue density mass located around the renal, aorta and iliac arteries
  • MRI for T1 relaxation time (excited protons return to relaxation)
  • Kidney ultrasound or special x-ray of the kidneys and ureters for obstructions
  • Low thyroxine levels
  • Autoimmune tests
  • Antinuclear antibodies and anti-smooth-muscle antibodies
  • IgG4 levels 
  • Intravenous pyelogram for ultrasound and x-ray
  • 18F-fluorodeoxyglucose for tissue uptake of glucose and 
  • PET (assess inflammation from oncology treatment and infectious diseases)
  • Fine needle aspiration biopsy for fibrous tissue and inflammatory cells  1  3   4  5   8  9   10


The main aim in treating idiopathic retroperitoneal fibrosis is to relieve any vascular obstructions and to prevent worsening of the condition.

Idiopathic retroperitoneal fibrosis is treated with:

  • withdrawal from drug causing the condition;
  • glucocorticoids and/or immunosuppressants;
  • tamoxifen (anti-estrogen, when glucocorticoid therapy is contraindicated); and
  • high doses of prednisone. 2  3   4  7  11

Secondary idiopathic retroperitoneal fibrosis is treated with: 

  • discontinuing the suspected drug;
  • antibiotics for infection;
  • oral high-dose glucocorticoids;
  • chemotherapy and radiation therapy; and
  • surgery for malignant tumours (recurrence rate of only 5 percent).  4  5   6  9

Relapse and long-term problems can occur after treatment and it is more frequent to occur in men. The use of corticosteroids and/or tamoxifen reduces risk of relapse.  3   4


Idiopathic retroperitoneal fibrosis can cause severe bilateral hydronephrosis (urine blockage with backup of urine and kidney swelling), ureteral compression and renal failure. 2 

Chronic residual hydronephrosis may occur. If untreated the severe complications can develop into end-stage renal failure. 2  

Prompt action is required to prevent permanent kidney damage with:

  • ureteral stent (tube to open ureter);
  • nephrostomy (drain urine from your kidney using a tube); and
  • surgical/laparoscopic ureterolysis (releasing pressure from ureter). 2  3


Kidney Health Australia

What type of specialist?

The specialists needed to diagnose, treat and monitor different stages of idiopathic retroperitoneal fibrosis are:

General Practitioner

Nephrologist (kidney disease)

Urologist Surgeon (kidneys, bladder, prostate, and male reproductive organs)

Endocrinologist (diabetes and endocrine disorders)

Vascular Surgeon and Cardiologist /Cardiac Surgeon