Differential Diagnosis for Patient Unable to Urinate

The inability to urinate, also known as urinary retention, can be caused by a variety of conditions. Here is a differential diagnosis organized into categories:

• Single Most Likely Diagnosis

  • Benign Prostatic Hyperplasia (BPH): This is a common condition in older men where the prostate gland enlarges, potentially blocking the flow of urine. The likelihood of BPH increases with age, making it a probable cause for urinary retention in this demographic.

• Other Likely Diagnoses

  • Urinary Tract Infection (UTI): Especially in women, UTIs can cause significant discomfort and lead to urinary retention due to pain or inflammation.
  • Neurogenic Bladder: Conditions affecting the nerves that control bladder function, such as diabetes, stroke, or spinal cord injuries, can lead to urinary retention.
  • Medication Side Effects: Certain medications, including anticholinergics, antihistamines, and some antidepressants, can cause urinary retention as a side effect.
  • Constipation: Severe constipation can put pressure on the urethra, leading to difficulty urinating.

• Do Not Miss Diagnoses

  • Acute Urinary Retention due to Kidney Stones: While not the most common cause, kidney stones can block the urethra and cause severe pain and urinary retention. Missing this diagnosis could lead to severe complications, including kidney damage.
  • Spinal Cord Compression: Conditions like spinal stenosis, herniated discs, or tumors can compress the spinal cord, affecting bladder control and leading to urinary retention. Early diagnosis is crucial to prevent permanent damage.
  • Post-Renal Transplantation Complications: In patients who have undergone kidney transplantation, urinary retention can be a sign of complications such as ureteral obstruction or rejection.

• Rare Diagnoses

  • Bladder Neck Contracture: Scarring at the bladder neck can cause obstruction and urinary retention. This condition is more common in men who have undergone prostate surgery.
  • Urethral Stricture: Narrowing of the urethra, often due to injury or infection, can cause urinary retention.
  • Interstitial Cystitis: A chronic condition causing bladder pressure, pain, and sometimes urinary retention, though this is less common.
  • Malignancies: Tumors in the bladder, prostate, or urethra can cause urinary retention, though these are less common causes compared to other conditions listed.