What are the diagnostic criteria for chronic prostatitis?

Diagnostic Criteria for Chronic Prostatitis

The diagnosis of chronic prostatitis requires a combination of clinical symptoms lasting at least 3 months, physical examination findings, and laboratory testing using the Meares-Stamey 4-glass test or its 2-specimen variant to differentiate between bacterial and non-bacterial forms. 1

Classification of Prostatitis

Chronic prostatitis is divided into two main categories according to the National Institutes of Health classification:

1. Chronic Bacterial Prostatitis (CBP)

   • Recurrent urinary tract infections with the same organism identified on repeated cultures 2
   • Accounts for a small percentage of chronic prostatitis cases

2. Chronic Prostatitis/Chronic Pelvic Pain Syndrome (CP/CPPS)

   • Accounts for more than 90% of chronic prostatitis cases 2
   • Presents as prostatic pain lasting at least three months without consistent culture results

Diagnostic Approach

Clinical Symptoms

• Pelvic or perineal pain (lasting at least 3 months)
• Lower urinary tract symptoms (frequency, urgency, dysuria)
• Sexual dysfunction or pain with ejaculation
• Symptoms without evidence of other urological conditions 3

Physical Examination

• Digital rectal examination to assess:
  • Prostate tenderness
  • Prostate consistency (to rule out prostate cancer)
  • Pelvic floor muscle tenderness 1, 2

Laboratory Testing

Meares-Stamey 4-Glass Test (Gold Standard)

• Collection of four specimens:

  1. First-void urine (VB1)
  2. Midstream urine (VB2)
  3. Expressed prostatic secretions (EPS)
  4. Post-massage urine (VB3) 1

• Interpretation: Positive for bacterial prostatitis if there is a 10-fold higher bacterial count in the EPS than the midstream urine 1

2-Specimen Variant

• Simplified version involving only:
  1. Midstream urine
  2. Expressed prostatic secretions 1

Additional Testing

• NIH-Chronic Prostatitis Symptom Index (NIH-CPSI) - recommended for quantifying symptoms and monitoring treatment response 4
• Urine culture to identify causative pathogens in bacterial forms
• PSA measurement (may be elevated during infection, should be rechecked 3 months after resolution) 4

Differential Diagnosis

Important conditions to rule out before diagnosing chronic prostatitis:

• Acute bacterial prostatitis
• Benign prostatic hyperplasia
• Urinary tract stones
• Bladder cancer
• Interstitial cystitis/bladder pain syndrome
• Pelvic floor dysfunction
• Prostate cancer 2, 5

Common Pitfalls and Caveats

1. Misdiagnosis: CP/CPPS is a diagnosis of exclusion and requires ruling out other urologic conditions 3

2. Inadequate Testing: Failure to perform proper segmented urine and prostatic fluid cultures can lead to misdiagnosis between bacterial and non-bacterial forms 1

3. Premature Antibiotic Treatment: Unless a patient presents with fever, antibiotic treatment should not be initiated immediately. The diagnostic work-up should be completed first, ideally within one week 6

4. Overlooking Non-Infectious Causes: More than 90% of chronic prostatitis cases are non-bacterial (CP/CPPS), so focusing solely on infectious etiology may miss the true cause 2

5. Inadequate Follow-up: Failure to reassess after treatment can lead to prolonged, ineffective therapy. Clinical reassessment after 2 weeks and urine culture at the end of treatment are recommended 4

The diagnostic approach to chronic prostatitis has evolved significantly, with increased recognition of the multifactorial nature of the condition and the importance of proper classification to guide treatment decisions.