Bleeding can occur with a bladder infection, though the blood may not always be visible. A bladder infection, medically termed cystitis, is a common lower urinary tract infection (UTI) caused by bacteria multiplying in the bladder. Blood in the urine, known as hematuria, is a common symptom of cystitis. It often presents alongside other uncomfortable symptoms like a frequent and urgent need to urinate and a burning sensation during urination.
Understanding Blood in Urine (Hematuria)
The presence of blood in the urine is described using two distinct categories based on how it is detected. Gross hematuria refers to visible bleeding, causing the urine to appear pink, red, or brownish. Only a small volume of blood is needed to change the color of the urine noticeably.
Microscopic hematuria is not observable with the naked eye. This type of bleeding is only detectable when a urine sample is examined under a microscope. Microscopic blood is a common finding when a patient with a urinary tract infection provides a urine sample for analysis. However, any finding of blood in the urine, whether visible or microscopic, warrants medical evaluation to determine the precise cause.
The Mechanism: Why Bladder Infections Cause Bleeding
The physiological reason a bladder infection causes bleeding relates directly to the inflammatory response to the bacterial invasion. Bacteria, most commonly Escherichia coli, multiply within the bladder and irritate the sensitive inner lining, called the mucosa. This irritation triggers an inflammatory reaction.
The inflammation causes the tissues of the bladder wall to become swollen and fragile. This damages the walls of the tiny blood vessels embedded just beneath the mucosal surface. When these small vessels are compromised, they leak red blood cells directly into the urine. The severity of the bleeding correlates with the extent of the inflammation within the bladder lining.
Recognizing Severe Symptoms and Complications
While blood in the urine can be a feature of a bladder infection, certain accompanying symptoms signal a more serious condition that requires immediate medical attention. A bladder infection can sometimes progress into a more serious upper tract infection, known as pyelonephritis, which affects the kidneys. Urgent symptoms include a high fever, typically over 100.4°F, and severe pain in the flank or back, located around the area of the kidneys.
Other signs of a potentially severe infection spreading beyond the bladder include persistent nausea and vomiting, or shaking chills. Passing large clots of blood in the urine is also a concerning symptom that warrants prompt evaluation. Bleeding without the typical pain, urgency, and frequency of a UTI, or heavy bleeding, may suggest other serious, non-infectious causes such as kidney stones and should also be evaluated quickly.
Diagnosis and Treatment of a Bladder Infection
A healthcare provider confirms a bladder infection by analyzing a urine sample. This involves a urinalysis, which checks for signs of infection such as white blood cells, nitrites, and red blood cells. A urine culture is often performed to identify the specific type of bacteria causing the infection.
Once the diagnosis is confirmed, treatment involves a course of antibiotic medication. Antibiotics eliminate the bacterial cause of the infection. As the bacteria are cleared and the inflammation resolves, symptoms like pain, urgency, and the presence of blood in the urine usually subside quickly.