What is prostatitis, its signs and symptoms, and causes?

Prostatitis: Definition, Signs and Symptoms, and Causes

Prostatitis is an inflammation and/or infection of the prostate gland that affects approximately 9.3% of men in their lifetime, with fewer than 10% of cases confirmed to have bacterial infection. 1, 2

Definition and Classification

Prostatitis is classified into four main categories according to the National Institute of Diabetes, Digestive, and Kidney Diseases classification system:

• Acute bacterial prostatitis (Category I): A urinary tract infection that includes infection of the prostate, typically with systemic symptoms 2
• Chronic bacterial prostatitis (Category II): Persistent bacterial infection of the prostate, often presenting as recurrent UTIs from the same strain 2
• Chronic prostatitis/chronic pelvic pain syndrome (Category III): Pelvic pain or discomfort for at least 3 months with urinary symptoms but no identifiable infection 2
• Asymptomatic prostatitis (Category IV): Inflammation without symptoms, usually discovered incidentally 3

Signs and Symptoms

Acute Bacterial Prostatitis

• Fever and chills 2
• Severe pain in the rectal or perineal area 4
• Lower urinary tract symptoms (frequency, urgency, dysuria) 5
• Obstructive voiding symptoms 5
• Cloudy or bloody urine 5
• Tender, swollen, and warm prostate on digital rectal examination 3

Chronic Bacterial Prostatitis

• Recurrent urinary tract infections from the same bacterial strain 2
• Persistent or intermittent pelvic pain 4
• Urinary symptoms (frequency, urgency, dysuria) 3
• Ejaculatory pain 6
• Normal or slightly tender prostate on examination 3

Chronic Prostatitis/Chronic Pelvic Pain Syndrome

• Pelvic pain or discomfort for at least 3 months 2
• Urinary frequency and urgency 2
• Sexual dysfunction 6
• Pain during or after ejaculation 6
• No evidence of bacterial infection on standard cultures 3

Causes

Bacterial Prostatitis

Acute Bacterial Prostatitis

• Gram-negative bacteria are responsible in 80-97% of cases: 2
  • Escherichia coli (most common) 2
  • Klebsiella pneumoniae 1, 7
  • Pseudomonas aeruginosa 1, 7
• Gram-positive bacteria: 1
  • Staphylococcus aureus 1
  • Enterococcus species 1
  • Group B streptococci 1

Chronic Bacterial Prostatitis

• Up to 74% of cases are due to gram-negative organisms, particularly E. coli 2
• Other pathogens include: 1
  • Proteus mirabilis 1, 7
  • Enterobacter species 1
  • Serratia marcescens 1

Non-bacterial Causes and Risk Factors

• Urinary tract abnormalities 5
• Benign prostatic hyperplasia 5
• Urinary stones 5
• Sexually transmitted infections 5
• Urinary catheterization 5
• Urological procedures 6
• Autoimmune processes 6
• Pelvic floor muscle dysfunction 6
• Neurological conditions affecting the bladder 6

Diagnostic Approach

Acute Bacterial Prostatitis

• Midstream urine culture to identify causative organism 1
• Blood cultures if systemic symptoms are present 5
• Digital rectal examination showing tender, swollen prostate (with caution to avoid vigorous prostate massage which may cause bacteremia) 3

Chronic Bacterial Prostatitis

• Meares-Stamey 4-glass test: Collection of first-void urine, midstream urine, expressed prostatic secretions, and post-massage urine 1
  • Positive if there is a 10-fold higher bacterial count in the expressed prostatic secretions than the midstream urine 1
• 2-specimen variant involving only midstream urine and expressed prostatic secretions 1

Common Pitfalls and Caveats

• Prostatitis is often overlooked in non-urological settings due to sometimes indeterminate symptoms 5
• Failure to recognize acute bacterial prostatitis can lead to: 5
  • Treatment failure and progression to prostatic abscess 5
  • Transition to chronic prostatitis requiring long-term antibiotics 5
  • Missing underlying diseases such as urinary stones, BPH, or malignancies 5
• Chronic pelvic pain syndrome is a diagnosis of exclusion and requires ruling out other causes of pelvic pain 2
• Vigorous prostatic massage should be avoided in acute bacterial prostatitis due to risk of bacteremia 3

By understanding the definition, signs and symptoms, and causes of prostatitis, clinicians can better diagnose and manage this common urological condition that affects a significant proportion of men during their lifetime.