From the Guidelines
Hematuria, or blood in the urine, is most commonly caused by urinary tract infections, kidney stones, and enlarged prostate in men, but can also be a sign of more serious conditions such as kidney disease, bladder or kidney cancer, and certain medications. The main causes of hematuria can be divided into two categories: benign and serious conditions. Benign causes include:
- Urinary tract infections (UTIs)
- Kidney stones
- Enlarged prostate in men
- Vigorous exercise
- Infection
- Trauma
- Menstruation
- Recent urologic procedure Serious causes include:
- Kidney disease (such as glomerulonephritis)
- Bladder or kidney cancer
- Certain medications like blood thinners (warfarin, aspirin, heparin)
- Physical trauma to the kidneys or bladder
- Certain inherited disorders like sickle cell anemia According to the study by Wolfman et al 1, the most common factors associated with the development of a urinary malignancy include gross hematuria, male gender, age >35 years, smoking, occupational exposure to chemicals, analgesic abuse, history of urologic disease, irritative voiding symptoms, history of pelvic irradiation, chronic urinary tract infection, exposure to known carcinogenic agents or chemotherapy, and chronic indwelling foreign body. It is essential to seek medical evaluation to determine the underlying cause of hematuria, as some causes are transient and harmless, while others require immediate medical attention. The presence of blood in urine occurs when red blood cells leak from any part of the urinary tract, from the kidneys to the urethra, and can appear as visibly red urine (gross hematuria) or be detected only under microscopic examination (microscopic hematuria) 1.
From the Research
Causes of Hematuria
The main causes of hematuria (blood in urine) can be classified into several categories, including:
- Benign conditions such as urinary tract infection, benign prostatic hyperplasia, and urinary calculi 2, 3, 4
- Malignancies, such as bladder cancer and urothelial carcinoma 5, 6
- Intrinsic renal disease and nephropathies 2, 4
- Urological emergencies, such as macrohematuria with blood clot, urinary retention, and new vegetative symptoms 6
Risk Factors and Evaluation
Patients with risk factors for genitourinary malignancy, macroscopic hematuria, or those in whom no cause is found, should be referred to a urological service for further investigation, including cystoscopy 3, 6 The evaluation of hematuria includes:
- Taking a patient history and performing a routine urine dipstick test 4
- Microscopic urinalysis 4
- Laboratory tests to assess renal function 4
- Imaging tests, such as ultrasound, computed tomography urography, or magnetic resonance urography 4
- Cystoscopy may be considered 4
Classification of Hematuria
Hematuria can be classified as either gross or microscopic, with gross hematuria having a greater risk of malignancy than microscopic hematuria 2 The risk of malignancy with gross hematuria is greater than 10%, and prompt urologic referral is recommended 2