What is the appropriate workup for an elderly male presenting with penile and rectal pain?

Workup for Elderly Male with Penile and Rectal Pain

An elderly male presenting with combined penile and rectal pain requires urgent evaluation for perirectal abscess with potential extension to the genitourinary tract, which can present atypically with penile discharge or scrotal symptoms. 1

Immediate Clinical Assessment

Focused History

• Duration and onset of pain (sudden vs. gradual) to differentiate acute infectious/inflammatory processes from chronic pain syndromes 2
• Associated symptoms: fever, urinary retention, penile discharge, scrotal swelling, or changes in bowel habits 3, 1
• Voiding symptoms: hesitancy, weak stream, incomplete emptying, or dysuria suggesting bladder outlet obstruction 3, 4
• Sexual history and function to assess for sexually transmitted infections or erectile dysfunction 5
• Medical comorbidities: diabetes (increases risk of infections and neuropathic pain), cardiovascular disease, neurologic conditions, and psychiatric history 5, 6
• Current medications: anticholinergics, alpha-agonists, opioids that may cause urinary retention 4

Physical Examination

• Vital signs: temperature, blood pressure, and pulse to assess for systemic infection 5
• Suprapubic examination: palpate for bladder distention indicating urinary retention 3, 4
• External genitalia: inspect for lesions, discharge from urethral meatus, scrotal swelling, testicular tenderness, or penile abnormalities 5, 3
• Digital rectal examination (DRE): This is mandatory to assess for fluctuant mass, tenderness, prostate size/consistency, and anal sphincter tone 5, 3, 4, 1
• Perineal and lower extremity neurologic examination: assess motor/sensory function to exclude neurogenic causes 4

Laboratory Investigations

Essential Tests

• Complete blood count (CBC): evaluate for leukocytosis suggesting infection or abscess 5
• Urinalysis with microscopy: detect infection, hematuria, pyuria, or glycosuria 5, 3, 4
• Urine culture: guide antibiotic therapy if infection suspected 3
• Serum creatinine: assess renal function, particularly if urinary retention or obstruction present 5
• Inflammatory markers: C-reactive protein (CRP), procalcitonin, and lactate if systemic infection or ischemia suspected 5

Additional Laboratory Tests

• Morning serum total testosterone: should be measured in all men with erectile dysfunction or genital pain, as testosterone deficiency is common in elderly men 5
• Prostate-specific antigen (PSA): consider if prostate enlargement detected and life expectancy >10 years 4, 7
• Glucose/HbA1c: if diabetes not previously diagnosed, as diabetic neuropathy can cause pelvic pain 5

Imaging Studies

Urgent Imaging Indications

• Contrast-enhanced CT scan of abdomen/pelvis: Perform urgently if perirectal abscess suspected based on fever, fluctuant rectal mass, or severe pain to detect abscess and assess for extension into genitourinary structures 5, 1
• Scrotal ultrasound with Doppler: if scrotal pain or swelling present to exclude testicular torsion, epididymitis, or abscess extension 5

Additional Imaging

• Renal and bladder ultrasound: assess for hydronephrosis, bladder abnormalities, or post-void residual if urinary retention suspected 4
• Transrectal ultrasound: may be indicated for prostate evaluation if BPH or prostatitis suspected, but defer if acute infection present 5

Specialized Testing (When Indicated)

• Post-void residual (PVR) measurement: via bladder scan or catheterization if urinary retention suspected 3, 4
• Uroflowmetry: if lower urinary tract symptoms present, with Qmax <10 mL/second suggesting severe obstruction requiring urgent urologic referral 4, 7
• Urethrocystoscopy or retrograde urethrogram: if urethral stricture suspected based on history or flow studies 4

Critical Diagnostic Considerations

High-Priority Differential Diagnoses

• Perirectal/ischiorectal abscess with genitourinary extension: can present with penile discharge as the primary symptom 1
• Acute urinary retention: requires immediate bladder decompression via catheterization 4
• Prostatitis/chronic pelvic pain syndrome: common in elderly men with pelvic pain 6
• Benign prostatic hyperplasia with bladder outlet obstruction: particularly if voiding symptoms present 5, 7
• Rectal prolapse with incarceration/strangulation: rare but life-threatening if present 5

Common Pitfalls to Avoid

• Failing to perform thorough DRE: perirectal abscess can present atypically with penile symptoms and may be missed without rectal examination 1
• Attributing all symptoms to benign prostatic hyperplasia: without excluding infectious or malignant causes 3
• Delaying imaging in systemically ill patients: CT scan should not be delayed if abscess or complicated infection suspected 5
• Missing urinary retention: always assess for bladder distention and measure PVR if voiding symptoms present 4

Immediate Management Priorities

• Bladder decompression via urethral catheterization if acute urinary retention present 4
• Urgent surgical consultation if perirectal abscess identified on examination or imaging 5, 1
• Empiric broad-spectrum antibiotics if systemic infection suspected while awaiting culture results 3
• Alpha-blocker therapy (e.g., tamsulosin) if urinary retention secondary to BPH, administered prior to catheter removal 4, 7

Indications for Urgent Specialist Referral

• Immediate urology referral: recurrent urinary retention, severe obstruction (Qmax <10 mL/second), hematuria, abnormal PSA, or neurological disease 3, 4, 7
• Immediate surgical referral: fluctuant rectal mass, signs of abscess, or systemic sepsis 5, 1
• Pain management/psychiatry referral: if chronic pelvic pain syndrome diagnosed after excluding organic causes 2, 6