Can Kidney Stones Cause Blood in Urine? Causes, Signs & When to See a Doctor

Blood in the urine, medically referred to as hematuria, can occur when a kidney stone lodges in the urinary tract and scratches the delicate lining of the kidneys, ureters, bladder, or urethra. Although kidney stones are cited as a possible cause, blood in the urine should be examined to establish the cause of the condition.

How Kidney Stones May Lead to Blood in Urine

Blood in urine can result when a kidney stone rubs or scratches the wall of the urinary tract. The stone passing through the urinary tract passages may cause friction to the sensitive tissues. Several factors lead to this symptom, including:

1. Irritation of Urinary Tract Lining

The inner lining of the urinary tract is sensitive. Stones passing through it can cause minor injuries or inflammation of the stone's rough surface, resulting in bleeding.

2. Blockage and Pressure

In some cases, stones can partially obstruct urine flow, which, in turn, can strain the urinary tract and potentially cause irritation or tissue damage, potentially leading to blood in the urine.

3. Microscopic Injury

Urine tests may occasionally detect microscopic traces of blood, even when no visible blood is present. This is called microscopic hematuria and can be observed when small stones irritate it to a minor degree.

According to studies, the amount of blood in the urine can vary widely. Some individuals may notice pink, red, or brown-coloured urine, while others may only learn about it through laboratory testing.

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What Blood in Urine Might Look Like

Blood in urine may appear differently depending on the amount of bleeding and the duration of blood presence. Common terms of description are:

• Pink or reddish urine

• Brown or cola-colored urine

• Tiny blood clots

• Urine that appears normal but shows blood on laboratory testing

Certain foods, medications, or dehydration may also cause changes in urine colour. This is why healthcare providers commonly use medical tests to detect the presence of blood.

Other Symptoms That May Occur With Kidney Stones

While blood in urine may occur with kidney stones, it is often accompanied by other symptoms. However, not all individuals exhibit the same signs. Here are some study-backed symptoms that are commonly reported:

• Sharp or severe pain in the lower back or side

• Pain that may spread to the lower abdomen or groin

• Painful urination

• Frequent urge to urinate

• Nausea or vomiting

• Smelling foul urine or cloudy urine

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When to See A Doctor For Blood in Urine

Blood in urine should generally be evaluated by a healthcare professional, even if it occurs only once. Although kidney stones are among the possible causes, many other diseases can also cause hematuria. Seek immediate medical care if you notice any of these symptoms:

• Urinary tract infections

• Kidney infections

• Enlarged prostate in men

• Inflammation of the bladder or kidney

• Certain kidney diseases

• Urinary system trauma or injury

How Doctors Diagnose the Cause of Blood in Urine

When blood is detected in urine, doctors usually recommend a step-by-step evaluation to understand the underlying cause. The purpose of the testing is not only to confirm the presence of blood but also to identify why it is occurring and whether kidney stones are present. Common diagnostic approaches include:

1. Urine Tests (Urinalysis and Urine Culture)

A urine test is one of the initial examinations. Through laboratory analysis, doctors may look for:

• Red blood cells, which ensure the presence of blood

• Crystals, which may indicate substances like calcium or oxalate that can form stones

• Signs of infection, such as bacteria or white blood cells

• Urine concentration levels, which may provide clues about hydration and stone risk

2. Imaging Tests (To Find Stones or Structural Problems)

If kidney stones are suspected, imaging tests may be used to visualise the urinary tract and identify any stones or blockages. Some of the most commonly used imaging modalities are:

• CT Scan (Computed Tomography): CT scans are often regarded as one of the most detailed imaging instruments, as they help to identify even the smallest stones and estimate their size and positioning.
• Ultrasound: Ultrasound is a non-invasive procedure and involves the use of sound waves to form images of the kidneys and bladder.  It may be preferred in certain situations, such as initial screening.
• X-ray: Some types of stones may be visible on X-ray, although not all stones appear clearly using this method.

These tests assist physicians in knowing the presence of a stone, the location and whether the stone is irritating or obstructing.

3. Blood Tests (To Measure Underlying Factors)

Blood tests are often used alongside urine and imaging tests to provide a broader picture of kidney health. They may help evaluate:

• Kidney functioning markers, including creatinine and urea

• Mineral levels, such as calcium and Uric acid.

• Signs of infection or inflammation.

• Metabolic disorders that can lead to stones

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Why Multiple Tests Are Often Needed

A deep analysis helps to make sure that the diagnosis is correct and that the most appropriate management approach can be considered. Doctors usually combine these tests because:

• Blood in urine can have multiple possible causes

• A single test may not necessarily detect kidney stones

• Some conditions may exist alongside each other (for example, a stone and an infection)

Bottomline

Blood in the urine may result from irritation or damage to the lining of the urinary tract as the stone passes through it. According to Dr Vishal, this symptom can vary in severity and, in some cases, may be detected only through laboratory tests.

As blood in urine can also be associated with several other health conditions, experts generally recommend seeking medical evaluation if this symptom occurs. Early assessment can help identify the cause and guide appropriate care.