Blood in Urine
Bright red blood in the urine causes instant alarm in a patient, and usually generates an emergency appointment or an out-of hours call. Blood may also be picked up by dipstick testing or MSU during the assessment of some other problem or in a routine medical. This is often less frightening even when disclosed to the patient, but should prompt an immediate referral for a full investigation.
Differential diagnosis
Common Diagnoses
- UTI
- Bladder Tumour
- Renal/Ureteric Stones
- Urethritis
- Prostatic Hypertrophy/Carcinoma of Prostate
Occasional Diagnoses
- Jogging and Hard Exercise
- Renal Carcinoma
- Chronic Interstitial Cystitis
- Anticoagulant Therapy
- Nephritis/Glomerulonephritis
Rare Diagnoses
- Renal Tuberculosis
- Polycystic Kidney Disease
- Blood Dyscrasias: Thrombocytopenia, Haemophilia, Sickle-Cell Disease
- Infective Endocarditis
- Schistosomiasis (Common Abroad)
- Trauma
- Ketamine-Associated Ulcerative Cystitis
Ready reckoner
Key distinguishing features of the most common diagnoses
| UTI | Bladder Tumour | Stones | Urethritis | Prostate | |
|---|---|---|---|---|---|
| Frank Blood | Possible | Possible | Possible | No | Possible |
| Dysuria | Yes | No | Yes | Yes | No |
| Urethral Discharge | No | No | No | Yes | No |
| Poor Urinary Stream | No | Possible | Possible | No | Yes |
| Loin Pain | Possible | No | Possible | No | No |
Possible investigations
Likely: Urinalysis, MSU, FBC, U&E, ACR/PCR.
Possible: PSA, ultrasound, plain abdominal X-ray, cystoscopy.
Small Print: Urethral swab, CT scan, urine cytology, renal biopsy, angiography.
- Urinalysis: Pus cells and nitrite in UTI. Pus cells alone in urethritis, TB and bladder tumour. Presence of protein suggests renal disease.
- Urine microscopy and culture to establish pathogen in infection. May show casts in renal disease.
- FBC and U&E help establish basic renal function and any associated anaemia or leucocytosis; consider PSA – usually elevated in prostatic carcinoma.
- ACR/PCR: To quantify any proteinuria.
- Urethral swabs if urethritis (best done at GUM clinic).
- If painless haematuria, ultrasound may show renal tumour or polycystic kidneys; CT may be more useful.
- Specialist investigations include renal imaging, cystoscopy, urinary cytology, renal biopsy and angiography.
Top Tips
- Microscopic haematuria in an asymptomatic menstruating woman can be ignored temporarily; repeat the urinalysis at mid-cycle.
- Remember that there are other less common causes of spurious haematuria – sometimes the blood may be coming from the rectum or vagina. Assess each case carefully and be prepared to rethink if symptoms persist but urological investigations prove negative.
- Some food pigments, beetroot and certain drugs (e.g. nitrofurantoin) can colour the urine red – confirm haematuria with urinalysis to save the patient unnecessary tests.
Red Flags
- Painless frank haematuria is an ominous sign indicating possible malignancy.
- Beware of recent onset of recurrent cystitis with haematuria in the elderly. The underlying cause may be a bladder tumour, especially if the haematuria (micro- or macroscopic) does not settle with treatment of the infection.
- Renal tumours can sometimes present with renal colic, as blood clots in the ureters mimic the effects of stones. A useful clue is that the bleeding may precede the pain.
- Haematuria requires emergency admission if there is significant blood loss or clot retention.
- Remember the possibility of chronic ketamine abuse in young people.