What is the differential diagnosis for dysuria in a male?

Differential Diagnosis for Dysuria in Males

Dysuria in males is most commonly caused by urinary tract infection (UTI) in men over 35 years, urethritis from sexually transmitted infections (STIs) in younger men, and bladder outlet obstruction from benign prostatic hyperplasia (BPH) in older men. 1, 2, 3

Primary Infectious Causes

Urethritis (Most Common in Younger Men)

• Gonococcal urethritis from Neisseria gonorrhoeae 1, 4
• Non-gonococcal urethritis (NGU) from:
  • Chlamydia trachomatis (most common NGU pathogen) 1, 4
  • Mycoplasma genitalium 1, 2
  • Ureaplasma urealyticum (but not U. parvum) 1
  • Trichomonas vaginalis 1, 4
• Symptoms include mucopurulent/purulent discharge, dysuria, and urethral pruritus, though many cases are asymptomatic 1
• In younger patients (<35 years), sexually transmitted organisms predominate 3

Urinary Tract Infection (Most Common in Men >35 Years)

• Coliform bacteria, particularly Escherichia coli, are the predominant pathogens 5, 3
• In older men, infection typically results from urinary stasis secondary to benign prostatic hyperplasia 3
• Complicated UTI presents with fever, rigors, altered mental status, flank pain, costovertebral angle tenderness, acute hematuria, or pelvic discomfort 1
• Catheter-associated UTI (CA-UTI) in patients with indwelling or recently removed catheters 1

Other Infectious Causes

• Prostatitis (acute or chronic bacterial) 4, 3
• Epididymitis/orchitis 4
• Viral pathogens: adenovirus, herpes simplex virus 4

Non-Infectious Causes

Bladder Outlet Obstruction

• Benign prostatic hyperplasia (BPH) with accompanying inflammation 1, 5
• Associated with detrusor overactivity and underactivity 1

Structural/Mechanical

• Urolithiasis (renal or bladder calculi) 5, 3
• Genitourinary malignancy 5, 3

Inflammatory/Irritative

• Bladder irritants (chemical, dietary) 2
• Interstitial cystitis/bladder pain syndrome 5
• Spondyloarthropathy 3

Traumatic

• Urethral trauma or inflammation from instrumentation 5
• Skin lesions affecting the genital area 2

Other

• Medication-induced dysuria 3
• Chronic pain conditions 2
• Psychogenic disorders 5

Critical Diagnostic Distinctions

Age-Based Risk Stratification

• Men <35 years: Prioritize STI evaluation (gonorrhea, chlamydia, M. genitalium) 4, 3
• Men ≥35 years: Consider coliform UTI and BPH-related complications first 3

Red Flags for Complicated Infection

• Fever, rigors, altered mental status 1
• Flank pain or costovertebral angle tenderness (suggests pyelonephritis) 1
• Recent urologic instrumentation or catheterization 1
• Immunocompromised state 1

Key Historical Features

• Sexual history: Recent new partners, unprotected intercourse (suggests STI) 2, 4
• Prior treatment: Men with dysuria alone (without discharge) are more likely to have received prior treatment 6
• Urethral discharge: Presence of both discharge AND dysuria is >90% specific for laboratory-confirmed urethritis 6
• Lower urinary tract symptoms: Frequency, urgency, hesitancy, weak stream (suggests BPH/obstruction) 1

Common Pitfalls

• Do not assume asymptomatic = no infection: Among men with treated urethritis who became asymptomatic at follow-up, 9% still had gonorrhea and 21% had NGU 6
• Do not overlook persistent urethritis: If initial testing for gonorrhea and chlamydia is negative but symptoms persist, test for Mycoplasma genitalium 2
• Do not treat empirically without considering complications: Virtual encounters without laboratory testing increase recurrent symptoms and antibiotic courses 2
• Do not ignore racial disparities: Gonorrhea rates are 40 times higher in Black adolescent males compared to White adolescent males in the United States 4