Hematuria, or red blood cells in the urine, can present microscopically or grossly as visible discoloration. In either case, hematuria is abnormal, except in young females with urinary tract infections. Bleeding originates from anywhere along the urinary tract, including the kidneys, ureters, bladder, prostate, and urethra.
Blood in the urine is often not a sign of serious disease, but hematuria is sometimes a marker for infection, stone disease, urinary tract cancer, or bladder cancer. Viral infections of the urinary tract and sexually transmitted diseases, especially in women, may also cause hematuria.
Signs and Symptoms
Symptoms include abdominal pain; decreased force of urination, hesitance, or incomplete voiding; fever; frequent and/or painful urination; pain in the flank or side; and urinary urgency. Asymptomatic microscopic hematuria has many causes, including life-threatening lesions.
In women, urethral and vaginal examinations will rule out local causes of microscopic hematuria. A catheterized urinary specimen is indicated if a clean-catch specimen is unobtainable. In uncircumcised men, the foreskin should be retracted to expose the glans penis. If a phimosis is present, a catheterized urinary specimen may be required.
In gross hematuria, the urine is red, pink, or dark brown and may contain small blood clots. However, the amount of blood in the urine is not a reliable indicator of the patient’s condition. Reddish urine not caused by bleeding (pseudohematuria) can be caused by excessive consumption of certain foods or medications. “Jogger’s hematuria” results from minor bladder hemorrhaging during running.
Diagnosing the Condition
In microscopic hematuria, the amount of blood in the urine is so small that it can only be detected by microscope. The American Urological Association’s definition of microscopic hematuria is three or more red blood cells per high-power field on microscopic evaluation of urinary sediment from two or three urinalysis specimens.
When hematuria is suspected, a midstream urine sample is applied to a chemically treated strip to see if it changes color, indicating blood in the urine. A positive result necessitates further examination.
Laboratory analysis includes urinalysis and microscopic examination of urinary sediment. The urine is examined for protein — an indication of kidney disease — and any evidence of urinary tract infection. The number of red blood cells per high-powered field is determined and the shape of the blood cells are evaluated to determine the origin of the bleeding.
The point when bleeding occurs during urination may indicate the location of the discharge. Initial hematuria at the onset of urination points to the urethra or prostate in men. Total hematuria throughout urination may originate from the bladder, ureter, or kidneys. Terminal hematuria at the end of urination points to the bladder or prostate in men.
In patients with white blood cells in the urine, a urine culture is performed and a urinary cytology is used to locate abnormal cells. A blood test measuring serum creatinine is useful. Patients with significant protein in their urine, abnormally shaped red blood cells, or elevated creatinine levels need further evaluation for renal disease.
A complete urologic evaluation for hematuria includes x-rays of the kidneys and ureters. Traditional testing involves an intravenous pyelogram, where dye is injected into the blood and x-rays are made as the kidneys excrete the dye. Some physicians use imaging studies, such as a computerized tomography (CT) scan or CT urography.
When there is elevated creatinine or an allergy to x-ray dye, magnetic resonance imaging or retrograde pyelography can help evaluate the upper urinary tract. In retrograde pyelography, dye is injected into the ureters from the bladder, and x-rays are taken. After the initial tests, the patient empties the bladder and has a final x-ray.
However, none of these studies affords bladder evaluation. A cystoscopic evaluation is usually performed under local anesthesia using a flexible cystoscope, enabling examination of the inner lining of the bladder and urethra.
Significant proteinuria, red cell casts, renal insufficiency, or dysmorphic red blood cells in the urine in asymptomatic microscopic hematuria should prompt evaluation for renal parenchymal disease.
When no specific cause is identified, bladder and kidney stones, cancer, and other lifethreatening diseases can be ruled out. Other causes that remain may correct themselves, or the hematuria may remain idiopathic.
In 10% of cases, no cause for hematuria is found. However, studies show that urologic malignancy is later discovered in 1% to 3% of patients with negative test results. Follow-up is then recommended.
When bladder cancer is detected using a uroscope, the cancerous cells are often scraped from the lining of the bladder without invasive surgery. With kidney cancer, surgical removal of the malignancy is possible in some cases; in others, removal of the entire kidney is required.
The American Urological Association suggests repeating urinalysis and urine cystoscopy at six, 12, 24, and 36 months. Immediate reevaluation with cystoscopy and repeat imaging should be performed in the case of gross hematuria, abnormal urinary cytology, or irritating urinary symptoms, such as pain with urination or increased frequency of urination. If none of these symptoms recurs within three years, no further urologic testing is needed.
Kidney stone disease is common in the United States, affecting one in 10 people and accounting for seven to 10 of every 1,000 hospital admissions. The incidence of stone disease is highest in patients between 30 and 45 years of age, while the condition declines in patients over 50. Treatment selection for stone disease depends on many factors, including the size and type of stone and the existence of underlying medical conditions.
Kidney stones are hard deposits of minerals that do not dissolve completely in the urine and grow slowly in the kidneys. Factors contributing to kidney stone formation include high levels of urine calcium, oxalate, or uric acid. Dehydration or low levels of urine magnesium, pyrophosphate, and citrate, in particular, also favor stone formation.
Approximately 85% of kidney stones are caused by urine hypercalciuria and mainly consist of calcium deposits, especially calcium oxalate. Calcium phosphate stones occur in patients with hormonal or metabolic disease, such as renal tubular acidosis or hyperparathyroidism.
Risk factors for developing kidney stones include inadequate fluid intake, dehydration, reduced urinary flow and volume, and increased levels of calcium, oxalate, uric acid, or other urinary chemicals. Other risk factors are low levels of urinary citrate and conditions that block or reduce urine flow. Medical conditions that increase risk include hyperparathyroidism, gout, hypertension, colitis, renal tubular acidosis, Crohn’s disease, and medullary sponge kidney. Poor diet may also increase the risk.
Performing a Diagnosis
Diagnosis of stone disease is based on medical history, physical examination, and imaging tests. Urine should be tested for hematuria or bacteriuria. Blood tests indicated include creatinine for kidney function, blood urea nitrogen and electrolyte for dehydration, calcium levels for hyperparathyroidism, and a complete blood count for infection.
The noncontrast computed tomography (CT) scan is the most frequently used imaging technique for diagnosing a kidney stone attack. Although a CT scan may miss small kidney stones, it can detect medical conditions with symptoms similar to stone disease. If detected, stones can be imaged with an abdominal x-ray to assess their size, shape, and orientation.
Ultrasound is preferred for patients who are pregnant, but it may not detect small stones. Most kidney stones can be located using intravenous pyelogram (IVP), which requires injection of a contrast agent followed by a series of x-rays. Only patients with normal kidney function can undergo IVP, and there is a small risk for allergic reaction to the dye. The IVP procedure can be lengthy if kidney blockage is severe.
Retrograde pyelogram is the most reliable means of imaging kidney stones but may require anesthesia. This technique is used when other imaging methods are unsuccessful.
Prevention and Treatment
Prevention strategies depend on individual risk factors and the type of stone present. Recommendations may include lifestyle modifications, such as increased fluid intake and dietary changes, as well as treatment of underlying medical conditions. Some patients should limit intake of meat, salt, and foods with high levels of oxalate.
Approximately 85% of kidney stones are small enough to pass during urination, usually within 72 hours of symptom onset. Most stones measure 4 mm or less in diameter, and about half of those measuring 5 mm to 7 mm will pass on their own. The best treatment for these stones is to drink up to two or three quarts of water per day, stay physically active, and wait. Walking is useful for helping stones to pass. Painkillers help with the pain associated with passing a stone.
Urinating through a strainer may be recommended so the stone can be recovered and analyzed. The mineral composition of the kidney stone will dictate treatment and future preventive measures. Medications, such as diuretics, and dietary restrictions, such as reduced calcium, are not generally required but may be prescribed. Stones that are not treatable with more conservative measures may require removal using the minimally invasive surgical procedures offered at Urology Associates of North Texas.
Minimally Invasive Surgical Procedures
Extracorporeal shock wave lithotripsy (ESWL) is the usual way to remove stones measuring up to 1.5 cm, which are located in any part of the urinary system. The patient is partially submerged in a tub of water or placed on a cushion during the procedure. The shock waves are moderately painful, so the procedure is performed with sedatives or anesthesia. The physician uses x-rays to monitor the location and status of the stone as shock waves pound the stone for about one hour. Each shock wave produces a loud noise, so patients must wear earplugs.
In many cases, the stone will begin to crumble after 200 to 400 shock waves. The sand-like particles that remain after treatment are easily passed in the urine. Side effects of ESWL include blood in the urine for a short time after the procedure, minor bruising on the back or abdomen, and discomfort with the passing of the stone fragments. Repeated ESWL treatments may be needed to completely break up some stones. This procedure should not be used to treat pregnant women or to remove struvite stones.
Percutaneous nephrolithotomy is recommended when ESWL is not effective or when the stone is very large. The surgeon inserts a nephroscope through a small incision in the patient’s back and into the back of the kidney. An ultrasonic probe or laser, fed through the nephroscope, is used to break up the stones for extraction. Percutaneous nephrolithotomy is performed under general anesthesia, and patients usually stay in the hospital for one to two days, with an additional recovery time of one to two weeks. Because all stones and fragments are removed through the nephroscope during the procedure, this surgery is recommended for people whose jobs or health conditions require that they be stone free.
Ureteroscopic stone removal is used to break up or remove stones lodged in the lower third of the ureter and is usually performed on an outpatient basis under general or local anesthesia. The surgeon passes a small ureteroscope through the bladder into the ureter to snare the stone. In some cases, the surgeon will shatter the stone using ultrasound, laser, or a technique called electrohydraulic lithotripsy. To relieve swelling and help with healing, the surgeon may place a small stent in the ureter for two to three days.
Parathyroid surgery is indicated when the stone is caused by overactive parathyroid glands. Usually a small benign growth in one of these glands causes it to be overactive, increasing the body’s calcium level. Removing the growth on the parathyroid gland cures the kidney stone problem in these patients.