Hematuria (adult)

Hematuria occurs when blood enters the urinary collecting system and is excreted in the urine. There are many etiologies for hematuria, and they range from benign and transient to gravely concerning. Hematuria can derive from the kidneys, ureters, bladder, prostate (in men), or urethra. Imaging can often be useful to determine the source.

Epidemiology

Malignancy is four times more frequent in macroscopic hematuria than in microscopic hematuria. Macroscopic hematuria is a common presentation of bladder cancer (80%) and renal cancer (~50%) ⁶. Approximately 5% (range 3-6%) of patients with macroscopic hematuria will have a malignancy ⁷.

Pathology

Hematuria can be considered in two main forms:

• frank (macroscopic) hematuria

  • frank hematuria is considered >1 mL of blood in the urine

  • red-colored urine (more red than brown) or clots in the urine is suggestive of a lower urinary tract source

• microscopic hematuria: 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

Etiology

There are many causes of hematuria, some of the more common include ^7,8:

• frank hematuria

  • infection, e.g. cystitis, prostatitis, pyelonephritis

  • urolithiasis

  • trauma

  • hydronephrosis

  • malignancy, e.g. renal cell cancer, urothelial cell carcinoma, prostate cancer

• microscopic hematuria

  • renal parenchymal (medical) disease, e.g. glomerulonephritis, interstitial nephritis, Alport syndrome

Treatment and prognosis

Frank hematuria is almost always evaluated clinically, with cystoscopy, and with imaging (e.g. CT urogram).

Imaging workup for microscopic hematuria is controversial. Some academic societies advocate that in the absence of a known benign etiology (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 hematuria has a high negative rate for malignancy, and suggest that instead of imaging all patients with microscopic hematuria, imaging should be reserved for higher-risk subsets ⁵.

Microscopic hematuria in children has a different treatment algorithm.