Guide To The Causes Of Blood In Urine (Hematuria)

Hematuria is the presence of red blood cells in an individual's urine and can be categorized in two different ways. Microscopic hematuria is the term used to describe blood cells in the urine that cannot be seen with the naked eye but can be seen through a microscope. Gross hematuria describes blood that can be seen in the urine with the naked eye. When an individual is affected by gross hematuria, their urine appears brown, red, or pink. It takes a nominal amount of blood to change the color of urine. Depending on its cause, other symptoms may or may not manifest in individuals affected by hematuria. Hematuria has many possible causes. Several diagnostic methods may be used to identify the underlying cause of hematuria, including a urinalysis, blood testing, CT scan, cystoscopy, kidney biopsy, and MRIs.

Urinary Tract Infection

An individual affected by a urinary tract infection may experience blood in their urine. The urinary tract consists of the kidneys; bladder; ureters, which are tubes that carry urine from the kidneys to the bladder; and urethra, the tube from the bladder to the outside of the body. Urinary tract infections are when any part of the urinary tract becomes infected by a harmful pathogen. Most urinary tract infections occur in an affected individual's bladder where urine is stored until it is ready to be emptied. Bacteria enter the body through the urethra and colonize in the bladder, and left untreated they can mobilize up the ureters and into the kidneys. Hematuria occurs when the infection causing pathogen damages the bladder walls, ureter walls, or tissues in the kidneys. The small vessels that supply these tissues become damaged as well, causing red blood cells to leak into the individual's urine stream. Most urinary tract infections begin with microscopic hematuria and will progress to gross hematuria without medical intervention.

Bladder Or Kidney Stones

An individual affected by bladder or kidney stones may have hematuria. Stones in the urinary tract typically begin inside of the kidney and then mobilize and enlarge in the ureters and bladder. The process of urinary tract stone formation may be referred to as renal lithiasis, urolithiasis, and nephrolithiasis. Stones that form in the urinary tract are not smooth and round but resemble deer antlers with sharp points and uneven edges. Smaller stones can be asymptomatic for several years, but a shift in position or changes in size can trigger symptoms. The irregular shape causes damage to the tissues of the kidneys, ureters, and bladder. The stone can penetrate the lining tissues of the urinary tract, rupturing and damaging the small vessels that supply them with blood and nutrients. Inflammation and irritation often result in the leakage of red blood cells into the urine. If a stone in the kidney or bladder obstructs the healthy flow of urine, it can back up into the kidneys and cause swelling and tissue damage. Once the stone passes or is removed, the backed-up urine can contain red blood cells that have leaked from damaged kidney tissues.