Table of Contents
- Introduction to Hematuria
Introduction to Hematuria
Hematuria is a term used to describe a condition characterized by blood in the urine. 1 Grossly, this may be visible as red to pink colored urine, which is called macroscopic hematuria. Often there are blood cells present in urine, which cannot be visualized from naked eyes, as the number of cells is so small that it barely affects the urinary color. This condition usually goes unnoticed until urine is examined using special techniques; hence, named microscopic hematuria. Hematuria is a medical symptom, depicting some underlying problem in the urinary tract and, thus, requires special attention towards management.
Both microscopic and macroscopic hematuria are consequences of entirely different pathologies. Usually, macroscopic hematuria means there is some in-growing mass like cancer, while microscopic hematuria is more likely to result from benign causes. 2
What is the Urinary Tract?
The urinary tract is the body’s waste removal system. It includes:
- Two kidneys
- Two ureters
- The bladder
- The urethra
A nephron is the microscopic structural and functional unit of a kidney. It is a specialized structure that consists of different groups of cells working together to filter blood and produce urine. Blood enters through afferent arterioles into a glomerulus (a ball like vascular structure) that lies in a cup called Bowman’s capsule. The blood is filtered, and all the filtrate goes from this cup into tubules (where all necessary re-absorption occurs), and finally into a collecting duct. Millions of collecting ducts drain into a calyx, and then these calyces join together to form the pelvis which enters into the ureter. The urine from both kidneys collects in the bladder through ureters. It then remains there until the bladder is full and then passes out of the body through the urethra. The damage to any structure throughout the urinary tract can cause hematuria.
Causes of Hematuria
Hematuria is not a disease, but rather a sign of an underlying pathology. The most crucial concern is to rule out cancer in these patients. 3 In addition, any injury, trauma, or infection in the urinary tract might lead to blood in the urine. Sometimes, however, certain foods like beets and berries, etc. may result in urine discoloration. This should not be confused with hematuria, as the later is always compounded with other symptoms. Common causes of hematuria are:
- Urinary tract infection (UTI): UTIs are among the most common causes of hematuria. 4 They are eight times more common in women than in men. 5 Infection in any part of the urinary tract, including the kidneys, results in inflammation (body’s natural reaction to injury) and ultimately damage to surrounding tissue. This also includes surrounding vessels, allowing blood passage through leaky vessels into the urinary tract, manifesting as blood in the urine. The hematuria seen in this situation is usually microscopic. Other symptoms that you might notice are urgency (a sudden desire to void), frequency, burning micturition (painful urination), and lower abdominal discomfort.
- Kidney stones: Kidney stones are another common cause of hematuria. 2 Usually, small-sized stones go unnoticed as they pass out easily without causing much trouble. Those of larger sizes, however, may get stuck anywhere in the kidney. The direct impact of stone on lining cells of the urinary tract results in destruction, ultimately allowing blood to leak into urine. The bleeding can be microscopic or gross, depending on the size and impact of the stone. The accompanying symptom that should ring the alarm is sudden and severe pain in the flank region.
- Kidney cancer: Kidney cancer is another significant cause of the presence of grossly visible blood in the urine.2 Many types of kidney cancers present with sudden gross hematuria not accompanied by pain. It is important to see your doctor at once if you experience these symptoms. Painful gross hematuria, on the other hand, is usually a result of kidney stones.
- Trauma: A sudden, severe direct blow to the kidney can cause injury to major blood vessels resulting in gross hematuria. Any other accidental damage to the kidney will also result in the same.
- Nephritic syndrome: As the name indicates, it is a collection of a number of symptoms. Three major ones include hematuria, proteinuria (protein in the urine), and mild hypertension. The primary pathology is the defective filtration system that is the nephron. The structure of nephron is damaged so severely that it allows large-sized contents of blood (protein and blood cells) to filter out, which normally are not allowed to pass.
- Excessive physical exercise: The benefits of exercise are well established, but an excess of everything is bad. The causes could be dehydration, trauma to the bladder, or excessive red blood cell breakdown. It is best to see your doctor to find out the definite cause.
- Inherited conditions: Many inherited pathological conditions can also cause hematuria. For example, sickle cell disease is a condition in which low oxygen levels in the blood cause deformation of red blood cells. These deformed RBCs, when stuck in small arteries, cause destruction and leakage of blood into the urine.
- Enlarged prostate: It is commonly seen in men over the age of 60. With advancing age, the prostate gland enlarges, producing significant urinary symptoms, including hematuria.
The diagnostic modalities suggested by your doctor will be focused on the investigation of primary causes1, 6 and ruling out the possibility of cancer 7. The treatment of the primary cause will help in the resolution of symptoms. The recommended investigations are:
- Complete blood count (CBC): CBC is one of the commonly ordered routine tests that give a clue about many diseases. The CBC report will help your doctor in establishing the severity of bleeding, ruling out infection, and looking for conditions that increase the risk of bleeding.
- Renal function tests (RFTs): These are blood tests used to evaluate the well-being of your kidney by looking at its function. These include:
- Serum creatinine: This blood test calculates the amount of creatinine present in the blood. Creatinine is one of the common waste products cleared by the kidneys.
- Blood urea nitrogen (BUN): It is another common waste product produced by the body. The levels of urea and nitrogen in your blood help in determining the functional capability of your kidneys.
- Glomerular filtration rate (GFR): The glomerulus is the most important unit of a nephron, working as a strainer, filtering the blood. It not only helps in assessing the function of the kidney but will also assist your doctor in assigning a stage to your kidney disease.
- Urinalysis: This is a urine dipstick test. Your doctor orders this test to look for protein and blood cells in urine. When a certain number of blood cells is observed on a high-power microscope from a urine sample, it is considered as microscopic hematuria.
- Culture and sensitivity: This is performed on the urine sample. Your doctor orders this test to look for bacteria in the urine. The bacteria require a special medium for growth, which varies depending upon their type. In the culture and sensitivity test, bacteria are given favorable conditions for their growth to see if they are really there. Then different antibiotics are tried in the laboratory with specialized techniques to look, which stops the growth of bacteria. This test is the gold standard for ruling out an infection.
- Urine cytology: Determining the type of cells in urine is important in establishing the diagnosis of different urinary tract disease.
- Radiological imaging: Radiological techniques are an essential tool in reaching a diagnosis of many chronic kidney conditions. They are carried out in two phases. 8
- First-line investigation: These are done to check for basic abnormalities like kidney stones, masses, and filling defects. These include conventional radiograph, renal ultrasound, and Intravenous urogram (IVU) combined with cystoscopy.
- Second-line investigation: These are carried out if the first-line investigations reveal any abnormality. These are highly specialized techniques using CT and MRI to see the extent of the damage. These include Multi-detector computed tomographic urography (MDCTU) and Magnetic resonance urography (MRU).
Note: All these tests are not always carried out for every patient. The most crucial concern in patients having hematuria is the presence of cancer. Though, many present with gross bleeding, some might experience asymptomatic microscopic hematuria. The testing is done according to the risk of cancer in a particular individual. The risk is calculated by combining various symptoms and factors such as age, gender, pain, duration, etc. Based on this, testing is divided into three groups:
- Low-risk group: These are patients who have minimal risk of cancer. In this group, only blood and urine test are done, and follow-up is recommended after six months. If on repeat testing, the abnormalities are still there along with persistent symptoms, the patient may be shifted to the intermediate-risk group.
- Intermediate risk group: This group is offered renal ultrasound and cystoscopic procedures to look into kidneys and bladder, respectively.
- High-risk group: These patients will have more advanced tests involving CT and MRI to look for the extent of disease.
The principal goal of treatment is to cure the primary cause of hematuria. Your doctor will suggest the treatment options according to your symptoms, investigation report, and the definitive diagnosis. This can be either medical or surgical treatment, again depending on the cause.
- Antibiotics: The first-line treatment to cure any infection is antibiotics. The culture and sensitivity test helps in prescribing the right medicine for you.
- Tranexamic acid: It has been used safely to treat severe bleeding in patients having chronic kidney disease secondary to polycystic kidneys. 9
- Drugs to shrink prostrate: These are effective for those having hematuria because of an enlarged prostate.
- Extracorporeal Shock wave lithotripsy: This is a non-surgical procedure in which high wave shock is given from outside the body to break the large stones that can easily pass out in the urine. It can be carried out in ambulatory surgical centers, such as an outpatient non-surgical procedure. The advantage is patients recover the same day and can continue with daily activities within a short amount of time.
Space occupying lesions like cysts and cancerous growths that cannot be treated with medicine require surgery. Surgical management varies depending upon the stage of kidney disease. This may involve preserving half or removing the entire kidney. For some inherited conditions like constricted ureter causing frequent obstruction, repairing is done.
- Kirkpatrick WG. Hematuria. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 184. Available from: https://www.ncbi.nlm.nih.gov/books/NBK294/
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- Alameel, T., & West, M. (2011). Tranexamic Acid treatment of life-threatening hematuria in polycystic kidney disease. International journal of nephrology, 2011, 203579. https://doi.org/10.4061/2011/203579