What is obstructive nephropathy?
In this article we will describe 10 facts about obstructive nephropathy.
1. Definition
Obstructive nephropathy (ON), also known as urinary tract obstruction, refers to a condition in which there is a blockage in the urinary system that prevents the normal flow of urine from the kidneys to the bladder.
Hydronephrosis is a common feature of obstructive nephropathy.
2. Causes
Common causes of obstructive nephropathy include:
- Benign prostatic hyperplasia (enlargement; BPH) in men
- Tumours (bladder, uterus/cervix/ovary in women, prostate in men)
- Kidney stones
- Urethral strictures
- Congenital abnormalities in the urinary tract
- Rare diseases like retroperitoneal fibrosis (RPF).
3. Impact on kidneys
Obstruction can lead to a buildup of pressure in the kidneys and urinary tract, which can impair kidney function and cause damage to the renal function over time.
4. Symptoms
Symptoms may include pain in the loin or lower back, frequent urination, difficulty urinating, blood in the urine; and signs of chronic kidney disease (CKD) such as ankle and leg swelling (oedema), elevated blood pressure, and changes in blood chemistry.
5. Diagnosis
Diagnosis involves medical imaging techniques like ultrasound, CT scan, or MRI. These identify the location and cause of the obstruction. Urine and blood tests can also provide information about kidney function and infection.
Hydronephrosis
A common consequence of obstructive nephropathy is the development of hydronephrosis, a condition where the kidney(s) become enlarged due to the accumulation of urine. This can further contribute to kidney dysfunction.
6. Treatment
Treatment aims to relieve the obstruction and restore normal urine flow. Depending on the cause and severity, treatment options include:
Initial treatment
- Urinary catheter placement to bypass the obstruction
- X-ray procedures on the kidneys (e.g. nephrostomy on one or both sides)
Later treatment
- Operations on the prostate gland in men
- Removing kidney stones
- Treating tumours
- Other surgical procedures.
7. Complications
If left untreated, obstructive nephropathy can lead to kidney damage, chronic kidney disease (CKD), and potentially kidney failure. Timely diagnosis and intervention are crucial to prevent these complications.
8. Acute vs chronic obstruction
Obstructive nephropathy can be acute (rapid onset, and short-term) or chronic (slow onset, long-term). Acute obstruction (also called ‘retention’, i.e. retention of urine) requires urgent intervention (usually a urinary catheter being placed into the bladder) to relieve the blockage and prevent damage.
9. Prognosis (outlook)
Prognosis depends on the underlying cause of the obstruction – but is generally good. An acute obstruction is usually reversible (and kidney function returns to normal, or baseline). It usually does not produce long-term damage to kidney function. Chronic obstruction can have long-term effects on renal function. But even in chronic cases, function often returns to normal or baseline.
For reasons that are not fully understood, in ON, even if kidney function after treatment is poor (e.g. blood creatinine over 300 mcmol/L or eGFR under 30 mls/min), it remains at this poor but adequate level. And dialysis and/or a kidney transplant is not needed. Though dialysis is needed in a minority of cases.
10. Prevention
Depending on the underlying cause, different preventative strategies are useful. In men and addressing conditions like a suspected enlarged prostate is important.
Remember that medical information can change over time, and most patients will need to be seen by a hospital kidney specialist. This is usually (initially) a urologist (kidney surgeon). If kidney function does not return to normal (or baseline) the patient needs to be seen by a nephrologist (kidney physician, i.e. non-surgeon) – who may need to follow them up long-term.
Summary
We have described what is obstructive nephropathy. We hope it has been helpful.
Last Reviewed on 9 April 2024