Benign prostatic enlargement
How the prostate surrounds the urethra below the bladder, why hormone-driven growth with age narrows that channel, and how the bladder’s response produces weak flow, frequency, urgency, night-time passing of urine and retention.
By the end, you can
- Describe the position and zones of the prostate and its relation to the urethra and bladder.
- Explain the role of dihydrotestosterone and ageing in benign prostatic hyperplasia.
- Distinguish the static and dynamic components of obstruction and relate them to treatment.
- Distinguish voiding from storage symptoms and explain how the bladder adapts to obstruction.
- Explain acute and chronic retention and back-pressure on the kidneys.
- Recognise the classic appearance, symptom score, flow and PSA values and tests of BPH, and explain how each main treatment acts on its mechanism.
What it is
Benign prostatic hyperplasia (BPH) is non-cancerous growth of glands and smooth muscle in the prostate’s transition zone, around the urethra. When it enlarges the gland (benign prostatic enlargement) and obstructs urine flow, it causes lower urinary tract symptoms. It is very common with age: most men over 70 have histological BPH, though many have few symptoms.
2 types to tell apart
- Voiding symptoms
- Weak or interrupted stream, hesitancy, straining, dribbling, incomplete emptying.
- Storage symptoms
- Frequency, urgency and waking at night to pass urine (nocturia).
US spelling: centre → center.
Normal function
A gland wrapped round the urethra
The {{prostate}} sits directly below the , in front of the rectum, and the first part of the urethra, the , runs through its centre. It makes part of the seminal fluid, including PSA, a protein that liquefies semen.
It has zones: the outer peripheral zone (about 70% of the gland, where most cancers arise), the central zone, and the small transition zone that wraps the urethra, where BPH arises. Its stroma contains smooth muscle with alpha-1 adrenergic receptors.
To store urine, the bladder wall (detrusor) relaxes and the bladder neck stays closed. To void, the detrusor contracts, the bladder neck opens and urine flows freely through the prostatic urethra.
| Feature | Share of gland | Main disease |
|---|---|---|
| Peripheral zone | About 70% | Most prostate cancers |
| Central zone | About 25% | Few diseases arise here |
| Transition zone | About 5%, around the urethra | Benign prostatic hyperplasia |
Underlying change · Step 1 of 4
Hormone-driven growth with age
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 2 of 4
A narrowed channel
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 3 of 4
The bladder works harder
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Consequences · Step 4 of 4
Retention and back-pressure
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Symptoms and signs
Symptoms, signs and findings
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Exam detail
Exam detail
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Treatment
How treatment works
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Recap
Recap
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Self-check
Check your understanding
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .