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what causes blood in urine

Blood in urine (hematuria) is a symptom, not a diagnosis, and it ranges from relatively mild causes (like a UTI) to serious ones (like cancer). It always deserves medical evaluation, especially if it’s new, persistent, or you see visible red or cola-colored urine.

Quick Scoop: Main Causes

Think of causes in a few big buckets:

  • Infections

    • Urinary tract infection (UTI)
    • Kidney infection (pyelonephritis)
    • Prostatitis (inflammation/infection of the prostate in men)
      These often cause burning with urination, frequent urges, foul-smelling or cloudy urine, and sometimes fever.

  • Stones and irritation

    • Kidney stones or bladder stones
    • Bladder inflammation (cystitis)
      Stones can scrape the lining of the urinary tract and cause sudden severe pain in the back or side, plus blood in urine.

  • Prostate problems (mostly in men over ~40)

    • Enlarged prostate (benign prostatic hyperplasia/BPH)
    • Prostate cancer
      These may cause weak urine stream, dribbling, getting up at night to pee often, or difficulty starting urination.

  • Kidney and urinary tract diseases

    • Glomerulonephritis (inflammation of the kidney’s filtering units)
    • Polycystic kidney disease
    • Other chronic kidney diseases
      These can cause microscopic blood (only seen on tests), sometimes with protein in urine, swelling in legs, or high blood pressure.

  • Cancer

    • Bladder cancer
    • Kidney (renal) cancer
    • Prostate cancer
      Painless visible blood in urine, especially in adults over 35–40, is a red- flag sign that must be checked urgently.

  • Trauma and procedures

    • Direct injury to kidneys or lower abdomen (falls, car accidents, contact sports)
    • Recent urinary procedures (catheter, cystoscopy, surgery)

  • Exercise and functional causes

    • Very vigorous or long-distance exercise (“runner’s hematuria”)
    • Recent heavy lifting
      Usually resolves after stopping the activity but still needs to be distinguished from more serious issues.

  • Blood and inherited disorders

    • Sickle cell disease or trait
    • Bleeding/clotting disorders (e.g., hemophilia)
    • Certain inherited kidney diseases

  • Hormone and gynecologic causes (in people who menstruate)

    • Menstruation mixing into the urine sample
    • Endometriosis involving the urinary tract

  • Medications and other factors

    • Blood thinners (e.g., warfarin, heparin, aspirin at certain doses)
    • Some chemotherapy drugs
    • Some antibiotics
    • Foods and pigments (like beets) can make urine look red but aren’t true blood

Mini Sections: Types of Blood in Urine

  • Gross hematuria
    • You can see the blood: pink, red, cola, or tea-colored urine.
    • More urgent to check because it can signal stones, infection, or cancer.
  • Microscopic hematuria
    • You can’t see it; it’s found on a dipstick or under a microscope.
    • Can still be important, especially if persistent or accompanied by other symptoms (protein in urine, high BP, flank pain).

When It’s an Emergency

Seek urgent or emergency care (same day, ER if needed) if blood in your urine comes with:

  • Clots in urine, or difficulty passing urine
  • Severe pain in back, side, or lower abdomen
  • Fever, chills, feeling very unwell
  • Inability to pee or very low urine output
  • Dizziness, fainting, or signs of major blood loss

What Doctors Usually Do

If you show up with blood in your urine, typical next steps include:

  1. History and exam
    • How long, any pain, fever, recent exercise, trauma, new meds, menstrual history, family history of kidney/urinary disease or cancer.
  2. Urine tests
    • Urinalysis (look for blood, infection, protein, crystals).
    • Urine culture (infection).
    • Sometimes urine cytology (looking for abnormal/cancer cells).
  3. Blood tests
    • Kidney function (creatinine, BUN).
    • Blood counts and clotting tests if needed.
  4. Imaging
    • Ultrasound, CT scan, or other imaging to look for stones, masses, or structural problems.
  5. Cystoscopy
    • A small camera placed into the bladder via the urethra, especially in older adults or those with risk factors for bladder cancer.

Story-Style Example

Imagine a 32‑year‑old runner who notices cola-colored urine right after a long marathon. They have no pain next day, and the urine goes back to normal. That might be exercise-induced hematuria. Now imagine a 58‑year‑old smoker who notices painless bright red urine on and off for a week. That pattern is more worrying for something like bladder cancer and absolutely needs prompt urologist evaluation.

What You Should Do If You Notice Blood

  • Do not ignore it or wait to see if it “just goes away,” especially if you are over 35–40 or have risk factors (smoking, chemical exposures, prior radiation, family history of kidney/bladder cancer).
  • Book a same‑week appointment with your primary care clinician or a urologist.
  • If accompanied by severe pain, fever, clots, or difficulty urinating, go to emergency care.

Bottom Line

  • Blood in urine can come from infection, stones, prostate issues, kidney disease, medications, or cancer.
  • It is not normal at any age and always deserves proper medical assessment.
  • Visible blood, especially without pain or in older adults, should be treated as urgent until evaluated.

Information gathered from public forums or data available on the internet and portrayed here.