From the Guidelines
Gross hematuria is a serious condition that requires prompt medical evaluation, as it may indicate underlying conditions such as urinary tract infections, kidney stones, trauma, or cancer, with a high association with malignancy of up to 30% to 40% 1. The causes of gross hematuria can arise from anywhere along the urinary tract and are generally divided into nephrogenic and urogenic causes.
- Renal parenchymal disease is the most common benign nephrogenic cause of hematuria 1.
- Common benign urogenic causes of hematuria include urolithiasis, infection, and benign prostatic hypertrophy 1.
- Malignant causes can occur anywhere in the urinary tract and are the main entity that must be excluded during the imaging evaluation of hematuria 1. The diagnostic workup for gross hematuria typically includes:
- Urinalysis
- Urine culture
- Complete blood count
- Kidney function tests
- Imaging studies such as CT urography or ultrasound
- Cystoscopy may be necessary to directly visualize the bladder 1. Patients with gross hematuria should seek immediate medical attention, especially if accompanied by pain, clots, or difficulty urinating, and should increase fluid intake to help flush the urinary system, avoid strenuous activities, and document any associated symptoms 1.
From the Research
Causes of Gross Hematuria
The causes of gross hematuria, which is the visible presence of blood in the urine, can be varied and may indicate a serious underlying condition. Some potential causes include:
- Infection, such as urinary tract infections 2, 3, 4
- Kidney stones 2, 3
- Trauma 3
- Exercise or spurious causes, such as foods, drugs, or menstruation 3
- Tumors, including bladder cancer 2, 3
- Glomerulonephritis, a type of kidney disease 5, 4
- Benign prostatic hyperplasia, a condition affecting the prostate gland 2
Risk Factors and Evaluation
It is essential to evaluate patients with gross hematuria to determine the underlying cause and assess the risk of malignancy. The risk of malignancy with gross hematuria is greater than 10%, and prompt urologic referral is recommended 2. A thorough history and physical examination should be performed to determine potential causes and assess risk factors for malignancy 2. Additional investigations, such as laboratory tests, imaging of the urinary tract, and referral to nephrology and urology subspecialists, may be necessary to rule out intrinsic renal disease and other potential causes 2, 4.
Diagnostic Approach
The diagnostic approach to gross hematuria involves a combination of clinical evaluation, laboratory tests, and imaging studies. The primary care physician should answer three key questions: (1) Is it really hematuria? (2) Should this patient with hematuria be worked up, and if so, how? (3) Should this patient with hematuria be referred, and if so, to which specialty? 6. A detailed family history can help establish the underlying cause in cases of familial hematuria 4. In some instances, additional non-invasive investigations, such as ultrasound imaging, urinary red cell morphology, and measurement of calcium and other solutes in the urine, may be needed to elucidate the nature of the hematuria 4.