What is haematuria?
Haematuria is the presence of red blood cells in the urine. It can range from obvious bleeding to the microscopic detection of a few red blood cells in a routine urine sample.
What are the causes of haematuria?
Blood in the urine can come from anywhere in the urinary tract: from the kidneys at the top down to the urethra (tube that carries urine from the bladder to the exterior).
In a person over 40 years of age with painless macroscopic haematuria, the most important cause to exclude is bladder cancer. Three main types of cancer occur in the bladder. The lining of the bladder, the ureter and the drainage system of the kidney consist of transitional cells. The most commonly found cancer is called transitional cell carcinoma. Cancers are usually named after the cells from which they originate.
Possible causes of bleeding from the upper urinary tract
- Kidney stones
- Carcinoma of renal parenchyma (“meat” of the kidney)
- Transitional cell carcinoma of the renal pelvis (cancer of the lining of drainage system of the kidney, see above)
- Angiomyolipoma (a benign tumour of the kidney containing large numbers of blood vessels and fat, prone to spontaneous bleeding)
- Pyogenic infections – which are infections caused by pus-forming bacteria
- Congenital (born with) disorders
- Polycystic kidney disease
- Renal cysts
- Bleeding disorders
- Sickle cell disease
- Anticoagulant therapy such as warfarin
- Vascular causes
- Renal emboli (blood clots)
- Renal vein thrombosis
- Interstitial renal disease
- IgA Nephropathy
Ureter (drainage tube of the kidney)
- Trauma (rare in isolation)
- Ureteric stones
- Ureteric tumours (rare)
- Transitional cell carcinoma (cancer of the lining of the ureter, see above)
Possible causes of bleeding from the lower urinary tract
- Haemorrhagic cystitis (severe cystitis associated with bleeding from the bladder)
- Schistosomiasis (Bilharzia)
- Transitional cell carcinoma (see above)
- Squamous cell carcinoma (see above)
- Adenocarcinoma (see above)
- Exercise induced haematuria (long distance running can cause the layers of the empty bladder to rub on each other, thereby causing bleeding)
- Cyclophosphamide – a drug used in the treatment of cancer
- Benign prostatic hyperplasia (BPH)
- Prostate cancer
- Prostatitis – infection of the prostate gland
- Urethral tumours (very rare)
- Urethritis – infection of the urethra
When is red urine not haematuria?
The most common cause of a false positive finding of haematuria is contamination of the urine sample with menstrual blood.
How is haematuria diagnosed?
- Urine test strip (dipstix)
- Urine microscopy
How is the cause of haematuria identified?
- Physical examination
- Urine analysis
- Microscopy and culture
- Cytology – looking at cells under the microscope
- Intravenous pyelogram
- CT scanning
How is haematuria treated?
All cases of haematuria should be fully investigated in order to identify the underlying cause. There is no single treatment of haematuria, as different causes will be treated differently. Discussing the treatment options of all the possible causes of haematuria is beyond the scope of this article.
When to call the doctor
Blood in the urine should always be taken seriously. The amount of haematuria does not correlate with the severity of the underlying cause. Anyone with even one episode of blood in the urine should see a doctor.