What Happens If a Kidney Stone Gets Stuck in the Urethra?

A kidney stone becomes a serious problem when it travels through the urinary tract and gets stuck in the urethra, the final and narrowest pathway through which urine is excreted.  While many kidney stones pass before reaching this point, if a stone becomes lodged in the urethra, it can obstruct urine flow, trigger intense pain at the urethral opening, lead to infection, or cause complete urinary retention, which requires urgent medical treatment.

What is the Urethra and Why Do Stones Get Stuck

The urinary tract consists of the bladder, ureters, kidneys and urethra. A stone passes through the ureters to the bladder after forming in the kidneys, and lastly, through the urethra to exit the body. 

Anatomy Differences of the Urethra

Male urethra: About 20 cm long with natural curves and narrow segments.

Female urethra: About three to four cm long and wider, so obstruction is less common but still possible.

Why Stones Get Stuck in the Urethra

The urethra is anatomically narrower than the bladder neck, which makes it a potential site of obstruction for the stone. A few factors that influence whether or not the stone will get stuck include:

• Stone size (most significant predictor)
• Stone shape and texture
• Previous urethral injury or narrowing (stricture)
• Prostate enlargement (in men)
• Low urine flow due to dehydration

Clinical Evidence on Stone Passage

According to the Turkish Journal of Urology and various clinical trials:

• Stones less than 4 mm pass in most cases
• Stones 5-7 mm have about a 50-60% chance of passing
• Stones larger than 7 mm rarely pass without medical help

Symptoms When a Kidney Stone Gets Stuck in the Urethra

A urethral stone often causes sudden, noticeable symptoms. These include:

1. Sharp, Localised Pain at the Urethral Opening

Pain can occur:

• At the tip of the penis (in men)
• At the urethral opening (in women)
• It may feel like a burning, stabbing, or tearing sensation

2. Difficulty Urinating or Weak Urine Stream

A partial or fully stuck stone causes:

• Dribbling
• Spraying urine
• Stop-start urination
• Feeling of incomplete emptying

3. Complete Urinary Blockage (Acute Retention)

Acute retention is one of the most disturbing complications. You may feel a strong urge to urinate, but nothing comes out. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), this is a medical emergency, and one should seek medical treatment right away.

4. Blood in the Urine (Hematuria)

In some cases, the stone scrapes the inner lining, which can lead to blood in urine, causing:

• Pink urine
• Red urine
• Brown urine

5. Visible Stone at the Urethral Opening

Dr Vishal notes that there are instances where the stone can be felt or seen when it gets stuck in the urethra. 

6. Swelling and Inflammation

When a stone is stuck in the urethra, the urethral opening may appear red, swollen, or irritated.

7. Infection Symptoms

If bacteria get trapped behind the blockage, it can lead to:

• Fever
• Chills
• Cloudy or smelly urine
• Burning sensation

Note: A kidney stone, along with infection, is very dangerous and needs immediate attention.

What Happens Inside the Body When the Stone Gets Stuck?

1. Urinary Obstruction Causes Pressure Build-Up

When a stone is stuck inside the body, urine cannot pass, and pressure grows in the:

• Urethra
• Bladder
• Ureters (if prolonged)
• Kidneys (uncommon but potential in the case of persistent obstruction)

2. Risk of Bladder Damage

When the bladder remains overstretched through retention, long-term dysfunction can occur.

3. Tissue Injury

When the stone has sharp edges, it can cause micro-tears, bruising, and inflammation inside the body.

4. Increased Risk of Urethral Stricture

A urethral stricture refers to the narrowing of the urethra caused by scar tissue from injuries, infections, or medical procedures. Chronic irritation due to a kidney stone can also cause scarring and narrowing.

5. Infection Risk

Stagnant urine allows bacterial growth, sometimes leading to urosepsis. Cleveland Clinic defines urosepsis as a life-threatening complication where a Urinary Tract Infection (UTI) spreads to the kidneys and enters the bloodstream.

Who Is at Higher Risk of a Urethral Stone Getting Stuck?

According to Dr Vishal, the following people are at a higher risk of developing a urethral stone getting stuck:

1. Men with Enlarged Prostate 

In men with Benign Prostatic Hyperplasia (BPH), the prostate becomes enlarged and physically narrows the urethral passage. This constriction creates a biological bottleneck, making the natural removal of kidney stones more difficult. Since the pathway is restricted, stones are more likely to get stuck, increasing the risk of pain and complications.

2. People with Urethral Strictures

These can be caused by the following:

• Previous infections
• Trauma
• Catheterisation
• Past surgeries

3. People Susceptible to Stones

Individuals who often form stones are predisposed to stones finding their way to the urethra.

4. Dehydration

Low urine output reduces flushing power, which in turn makes the stone get stuck inside the body.

5. Sedentary Lifestyle

Reduced movement throughout the day also settles the stone within the body, which slows stone migration.

Emergency Warning Signs To See A Doctor

Seek immediate medical attention if you experience any of the following symptoms:

• Complete inability to urinate
• Fever with chills
• Nausea or vomiting
• Extreme pelvic or urethral pain
• Visible swelling around the genitals
• Confusion or dizziness

These symptoms could be a sign of infection and obstruction, which can spread rapidly.

How Doctors Diagnose a Urethral Stone

Dr Vishal points out that experts may use one or a combination of the following to diagnose a urethral stone:

1. Medical History and Symptom Assessment: Doctors ask about the duration of symptoms, pain severity, urine output, history of previous stones, fever or any other infection symptoms.

2. Physical Examination: This may include checking bladder fullness, signs of swelling, and/or a visible stone at the opening.

3. Ultrasound: Shows urine retention and bladder distension.

4. Low-Dose Non-Contrast CT Scan: This is the gold standard for stone detection. It identifies the exact stone location, its size, the total number of stones, and whether it has reached the kidneys.

5. Urinalysis: This helps to check for blood, infection, crystals, and white blood cells.

Can a Kidney Stone Stuck in the Urethra Be Removed Without Surgery?

Yes, kidney stones stuck in the urethra or ureter can often be removed without traditional open surgery, especially if they are small, i.e. less than 5mm. Dr Vishal adds, “Non-surgical methods include increasing water intake to flush the stone out, using medical expulsion therapy (alpha-blockers) to relax muscles, or using shockwave lithotripsy to break it.”

Procedures Used to Treat Kidney Stones Stuck in the Urethra

There are two main types of medical procedures used by doctors to surgically remove kidney stones stuck in the urethra. These include:

1. Cystoscopy 

Cystoscopy is a process where a doctor inserts a thin, flexible tube with a camera (medically known as a cystoscope) through the urethra to examine the bladder lining. It is primarily used to diagnose urinary conditions, check for blockages, or treat small issues like minor stones or polyps.

2. Ureteroscopy 

Another procedure is ureteroscopy, where a doctor inserts a thin, flexible tube with a camera through the urethra to see, remove and/or break the stone, which usually requires anaesthesia or heavy sedation.

Bottomline

A kidney stone stuck in the urethra can cause severe pain, blockage, and infection that may require emergency treatment. While small stones may pass naturally, larger stones often need medical removal. With timely diagnosis and treatment, recovery is fast, and long-term complications can be avoided. Clinical evidence and medical experts suggest that staying hydrated and following preventive strategies significantly lowers the risk of recurrence.