Scrotal pain and haematuria

Acute Scrotal Pain: Testicular Torsion vs Epididymo-orchitis

Acute scrotal pain demands urgent clinical evaluation to distinguish ischaemic emergencies from infectious conditions.

Testicular Torsion

• Pathophysiology: Arises from an anatomical variation known as the "bell-clapper deformity", where the tunica vaginalis inserts abnormally high on the spermatic cord, leaving the testis and epididymis unanchored and free to rotate within the tunica vaginalis. Twisting of the spermatic cord occludes venous outflow, producing rapid venous congestion and swelling, followed by arterial thrombosis and complete testicular infarction.
• Clinical Presentation: Sudden onset of severe, unrelenting unilateral scrotal pain, frequently awakening the patient from sleep or following physical exercise. Associated with nausea and vomiting. Physical examination reveals an exquisitely tender, swollen, high-riding testis with a horizontal or transverse lie.
• Key Physical Signs:
  • Reflexes: An absent cremasteric reflex raises concern, but preservation does not exclude torsion; the history and full examination determine urgency.
  • Prehn sign: Relief or lack of relief on elevation is unreliable and must not determine whether urgent exploration is needed.
• Emergency Management & The 6-Hour Golden Window:
  • Testicular salvage exceeds $90\%$ if detorsion occurs within 6 hours of pain onset, but falls to $< 50\%$ at 12 hours and $< 10\%$ after 24 hours.
  • Never delay operative exploration for Doppler ultrasound: If testicular torsion is suspected clinically, transfer the patient directly to the operating theatre for immediate scrotal exploration.
  • Surgery: Prompt exploration with detorsion, viability assessment and usually bilateral fixation addresses the common bilateral predisposition. Remove an unsalvageable testis for non-viability, not a presumed need to prevent antisperm antibodies.

Acute Epididymo-orchitis

• Pathophysiology: Retrograde ascent of pathogenic bacteria from the urethra or bladder along the vas deferens into the epididymis and testis.
• Microbial Aetiology:
  • Microbiology: Assess sexual exposures, insertive anal intercourse, urinary pathology and instrumentation. STI and enteric risks are not reliably divided by age 35; obtain first-catch NAAT and appropriate urine culture.
• Clinical Presentation: Gradual onset of unilateral scrotal pain and swelling over several days, often accompanied by dysuria, frequency, urethral discharge, and low-grade pyrexia. On examination, the epididymis is palpably thickened and tender behind the testis. The cremasteric reflex is intact, and Prehn sign is positive (scrotal elevation relieves pain).
• Management (Australian eTG Guidelines):
  • Treatment: Use the current Australian STI/local urology regimen for the suspected organisms, test for other STIs, arrange partner management and provide abstinence advice. First exclude torsion; antibiotics cannot salvage a torsed testis.
  • Enteric risk: Choose antibiotics using culture, local resistance, renal function and exposure; do not assume every older person needs ciprofloxacin or every younger person has an STI.
  • Supportive: Scrotal support (tight-fitting briefs), bed rest, ice packs, and oral NSAIDs.

Clinical comparison: Differential Diagnosis of the Acute Scrotum

• Age Group: Testicular Torsion: Bimodal: neonates and 12–18 years; Epididymo-orchitis: Any age; peaks 18–35 and $> 50$ years; Torsion of Appendix Testis: School-age boys (7–12 years)
• Onset of Pain: Testicular Torsion: Sudden, dramatic (minutes); Epididymo-orchitis: Gradual over 24–48 hours; Torsion of Appendix Testis: Acute to subacute
• Testis Lie: Testicular Torsion: High-riding, horizontal/transverse; Epididymo-orchitis: Normal vertical lie; Torsion of Appendix Testis: Normal vertical lie
• Cremasteric Reflex: Testicular Torsion: Absent; Epididymo-orchitis: Present; Torsion of Appendix Testis: Present
• Prehn Sign: Testicular Torsion: Negative (pain persists/worsens); Epididymo-orchitis: Positive (elevation relieves pain); Torsion of Appendix Testis: Negative or equivocal
• Systemic Symptoms: Testicular Torsion: Nausea and vomiting common; Epididymo-orchitis: Fever, dysuria, urethral discharge; Torsion of Appendix Testis: Usually absent
• Diagnostic Hallmark: Testicular Torsion: Clinical diagnosis; surgical exploration; Epididymo-orchitis: First-catch urine PCR; midstream urine; Torsion of Appendix Testis: Blue dot sign on upper scrotal transillumination
• Primary Treatment: Testicular Torsion: Immediate bilateral scrotal exploration; Epididymo-orchitis: Targeted antimicrobial therapy; Torsion of Appendix Testis: Bedside reassurance, NSAIDs, rest

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Investigation of Haematuria

Haematuria is classified as macroscopic (visible / frank) or microscopic (non-visible). Macroscopic haematuria carries a $20\%\text{ to }30\%$ risk of underlying urological malignancy (most commonly urothelial bladder carcinoma, followed by renal cell carcinoma and prostate cancer) and mandates complete investigation.

Microscopic Haematuria

• Defined as $\ge 3\text{ red blood cells per high-power field (RBC/HPF)}$ on automated or manual microscopy of a fresh, midstream clean-catch urine specimen.
• Urine dipstick testing is highly sensitive for haem pigment (detecting free haemoglobin and myoglobin as well as intact RBCs), but has a significant false-positive rate. Confirm isolated dipstick haematuria with microscopy where appropriate, but do not use a negative dipstick or a delayed sample to dismiss or postpone assessment of visible haematuria.

Glomerular vs Extraglomerular (Urological) Bleeding

• Glomerular Haematuria: Dark brown, tea-coloured, or "cola-coloured" urine. Microscopy demonstrates dysmorphic erythrocytes ($> 80\%$) and red blood cell casts. Often accompanied by significant proteinuria ($> 0.5\text{ g/day}$) and impaired renal function. Points to glomerulonephritis (IgA nephropathy, post-streptococcal glomerulonephritis, ANCA vasculitis) and warrants nephrology referral.
• Extraglomerular / Urological Haematuria: Bright red or pink urine, frequently containing formed blood clots. Microscopy reveals isomorphic (normal-shaped) erythrocytes with minimal or absent proteinuria. Points to calculi, neoplasia, infection, or trauma.

Mandatory "Triple Assessment" for Macroscopic Haematuria

Any adult presenting with unexplained macroscopic haematuria—even if painless, transient, or self-limiting—requires comprehensive triple assessment:

1. Clinical Evaluation: Comprehensive history (smoking pack-years, occupational exposures to aromatic amines/dyes in paint, textile, or rubber industries, cyclophosphamide exposure) and physical examination including digital rectal examination (DRE).
2. Upper Urinary Tract Imaging: Multiphase CT Urography (CT IVU) is the imaging modality of choice, acquiring non-contrast (detects renal calculi), nephrographic (evaluates renal parenchymal masses), and delayed excretory phases (opacifies collecting systems and ureters to reveal filling defects).
3. Lower Urinary Tract Inspection: Flexible Cystoscopy under topical local anaesthetic gel. Rigid cross-sectional imaging cannot reliably detect flat urothelial carcinoma in situ (CIS) or small papillary mucosal lesions of the bladder; direct mucosal visualization is mandatory.

• Haematuria on anticoagulants: Anticoagulants can cause or amplify bleeding, but visible haematuria still requires assessment for structural disease, infection and malignancy. Check severity, kidney function and anticoagulant effect; do not dismiss the symptom as harmless drug-related bleeding.

Primary references (checked 7 October 2026): Australian STI guidance.