Haematuria occurs when blood enters the urinary collecting system and is excreted in the urine. There are many aetiologies for haematuria, and they range from benign and transient to gravely concerning. Haematuria can derive from the kidneys, ureters, bladder, prostate (in men), or urethra. Imaging can often be useful to determine the source.
Haematuria can be considered in two main forms:
- frank (macroscopic) haematuria
- microscopic haematuria
Frank haematuria is considered >1 mL of blood in the urine. Red-coloured urine (more red than brown) or clots in the urine is suggestive of a lower urinary tract source.
Microscopic haematuria may be either symptomatic or asymptomatic and is defined as ≥3 red blood cells per high-powered field (HPF) on 2 out of 3 urinalysis specimens 2.
Treatment and prognosis
Frank haematuria is almost always evaluated clinically, with cystoscopy, and with imaging (e.g. CT urogram).
Imaging workup for microscopic haematuria is controversial. Some academic societies advocate that in the absence of a known benign aetiology (such as vigorous exercise, infection, or menstruation), then a CT urogram is warranted 3,4. If the patient has known renal disease then an ultrasound of the kidneys and bladder may be more appropriate.
Some feel that the imaging workup in the setting of microscopic haematuria has a high negative rate for malignancy, and suggest that instead of imaging all patients with microscopic haematuria, imaging should be reserved for higher-risk subsets 5.
Microscopic haematuria in children has a different treatment algorithm.
- 1. Rose BD. Pathophysiology of renal disease. McGraw-Hill Professional. ISBN:0070536295. Read it at Google Books - Find it at Amazon
- 2. Yun EJ, Meng MV, Carroll PR. Evaluation of the patient with hematuria. Med. Clin. North Am. 2004;88 (2): 329-43. doi:10.1016/S0025-7125(03)00172-X - Pubmed citation
- 3. Mariani AJ, Mariani MC, Macchioni C et-al. The significance of adult hematuria: 1,000 hematuria evaluations including a risk-benefit and cost-effectiveness analysis. J. Urol. 1989;141 (2): 350-5. Pubmed citation
- 4. Davis R, Jones JS, Barocas DA et-al. Diagnosis, evaluation and follow-up of asymptomatic microhematuria (AMH) in adults: AUA guideline. J. Urol. 2012;188 (6): 2473-81. doi:10.1016/j.juro.2012.09.078 - Pubmed citation
- 5. Ziemba J, Guzzo TJ, Ramchandani P. Evaluation of the Patient with Asymptomatic Microscopic Hematuria. Acad Radiol. 2015;22 (8): 1034-7. doi:10.1016/j.acra.2015.02.003 - Pubmed citation