Introduction

The acute scrotum is a ‘constellation of new-onset pain, swelling and/or tenderness of intra-scrotal contents^’ (1). In this article, we will review the limited number of differentials.

Please note that a single clinical feature is not the confirmatory to a particular differential but the whole clinical picture will need to be considered when making a diagnosis.

Anatomy

Embryology

• Embryologically the testicle develops in the posterior abdominal wall between weeks 6-7.
• They begin their descent down the abdominal cavity with the aid of the gubernaculum from week 12 towards the scrotum via the inguinal canal.
• The testicle will take a layer from each facial covering of the abdominal wall as it passes during its descent into the scrotum. This will form the layers of the scrotum.

Basic Anatomy

Scrotum

The scrotum is the cutaneous area that has many layers

• Skin – most superficial
• Dartos muscle
• External spermatic fascia – derives from external oblique aponeurosis
• Cremasteric muscle & fascia – derives from internal oblique
• Internal spermatic fascia – derives from transversus abdominis
• Tunica vaginalis – derives from parietal peritoneum
• Tunica Albuginea – derives from visceral peritoneum

Figure 1: Diagram showing layers of the scrotum (2).

Testis

• The testes lie in the scrotum vertically, connected to a spermatic cord via an epididymis.
• The Testis is the site of sperm production
• Blood supply: Testicular artery and testicular vein
• Lymphatics: Para-aortic lymph nodes

Epididymis

• The epididymis is the storage reservoir for the sperm
• Sperm will mature whilst in the epididymis
• This is a single heavily coiled duct that contains 3 parts:
  • Head – connected to the testes, where the sperm is transported from the testis into the epididymis
  • Body
  • Tail – connects to the vas deferens in the spermatic cord

Figure 2: Diagram of testis and epididymis together (3)

Spermatic Cord

This is a collection of structures that run from the abdomen into the scrotum via the inguinal canal.

Assessment of an acute scrotum – History

Key things that need to be elicited from a focused history include:

• Duration of symptoms
• Onset of symptoms – sudden onset or gradual onset
• Is the pain constant or intermittent
• Exacerbating and relieving factors of pain (pain worse on movement is more associated with epididymitis or epididymo-orchitis)
• Associated symptoms
  • LUTS – frequency, urgency, hesitancy, intermittent stream, double voiding, nocturia
  • UTI – dysuria, fever,
  • STI -UPSI, number of partners,

Assessment of an acute scrotum -Examination & Investigations

Always have a chaperone

• Patient lying supine with key area exposed (abdomen to middle of thighs)
• Size and position of the testis
• Lie of the testes
• Assess the spermatic cord for bulk
• If there is swelling/mass
  • Can you get above the swelling or mass
    • If you cannot get above the mass, then this is likely to be an inguinoscrotal hernia
  • Is the mass/swelling separate from the testes
  • Is the mass/swelling cystic or solid
• In absence of mass/swelling
  • Is the point of tenderness in the testes or epididymis
• Assessment of cremasteric reflex
  • Stimulation of the genitofemoral nerve on the medial thigh to see if scrotum rises in response.
• Ask patient to stand to see lie of testes with gravity
• Phren’s sign
  • With patient standing up, elevate the affected hemi-scrotum.
  • If pain resolves- likely epididymo-orchitis
  • If pain continues – more likely torsion

All examinations must be performed with an examination of the abdomen and hernial orifices.

The subsequent investigation will depend on the clinical features and differentials generated.

Differentials

The key differentials involve:

• Testicular Torsion
• Epididymo-orchitis  
• Fourniers Gangrene
• Torsion of hyatid of Morgagni
• Varicocele
• Hydrocele
• Epididymal cyst
• Testicular trauma

Testicular Torsion

• A key Urological Emergency, where the spermatic cord has twisted, restricting blood supply to the testicle
• Delayed presentation or diagnosis can lead to loss of testicle (see below)
• Commonly affect boys after birth and during puberty
  • Approximately 10% occur in adults
• Rarely occurs after the age of 40 (oldest reported case is 90 years old)
• Risk factors
  • Cryptorchidism
  • Bell-clappers deformity – abnormal fixation of the tunica vaginalis over the proximal spermatic cord as opposed to just the testis.  increased risk of twisting
• Clinical features
  • Symptoms
    • Sudden onset unilateral scrotal pain
      • Can radiate to the abdomen
      • Will settle once the testis is no longer viable
    • No relieving or exacerbating factors
      • Does not resolve on analgesia
    • May have associated nausea and vomiting
  • Signs
    • High riding testis
    • Horizontal testicular lie
    • Hard swollen testicle
    • Bulky spermatic cord
    • Loss of cremasteric reflex
    • Negative Phren’s sign
• Investigation
  • Can perform a urine dip to exclude infective causes
  • If uncertainty you may consider performing a TWIST score based on the clinical features to aid decision making (5)
  • This is a Clinical Diagnosis, therefore investigations that may delay treatment should not be considered
• Management
  • Scrotal Exploration
    • If the testis is viable – Bilateral orchidopexy
    • If testis is not viable – Orchidectomy to affected side and orchidopexy to contralateral side

When performed within 6 hours of onset of torsion, there is a 97.2% chance of salvaging the testicle. This reduces with further delays as seen from the table below(6).

Figure 3 Comparison of Bell Clappers deformity and a normal testis (4)

Epididymo-orchitis

If formation of abscess – may need to go for surgery to drain abscess

Infection or inflammation affecting the epididymis +/- testis

Associations

• Urinary tract infections

Sexually transmitted infections

Risk factors

• Diabetes

• Steroid use

Immunocompromised

Clinical features

• Symptoms
  • Insidious onset of pain + swelling
    • Pain will persist for longer 
  • Will have a preceding signs of infection
    • Fever, rigors
    • Dysuria
    • Haematuria
    • Penile discharge
  • In event of UTI – worth clarifying LUTS, especially in men as chronic urinary retention will precede a UTI that can lead to epididymo-orchitis
  • Significant sexual history- multiple partners, UPSI, previous STIs

Signs

• Variable depending on extent of infection

• Tenderness over the epididymis and/or testes

• Swollen testes

• May have a reactive hydrocele present

Area of fluctuation in keeping with formation of abscess

Investigation

• Post void bladder scan

• Urine dip

• STI screen (if suspect STI)- normally performed at GUM clinics
  • First pass urine or Urethral swab for N. gonorrhoeae and Chlamydia trachomatis.
  • HIV test – if suspected and patient has consented

• FBC, U/E, CRP, Coagulation

USS testes – if concerns regarding formation of abscess

Management

• Antibiotics based on underlying source of infection (UTI or STI) and trust guidelines.

• Generally, younger men (<40 years old) would be treated for suspected STI, whereas older men (>40 years old) would be treated for suspected UTI.
  • However, it is very important that a careful history covering risk lower urinary tract symptoms, sexual history and risk factors for UTIs are taken in order to prescribe the most appropriate antibiotics.

Fourniers Gangrene

Figure 4 A picture of Fourniers Gangrene (7)

• Necrotising fasciitis of the scrotum and perineal area
• Involves the synergistic action of aerobes and anaerobes
• Risk factors
  • Diabetes Mellitus
  • Alcoholics
  • Bed bound
  • Poor nutrition
  • Unable to clean
• Will have features of necrotic patches, purulent area over generalised erythema and a foul-smelling odour. There will be noted crepitus over the affected area.
• Will need an emergency escalation to the Urology team as patient will need debridement.
• Initial Management (whilst Urology team are on their way)
  • Bloods – FBC, U/Es, CRP, Coagulation screen, Blood glucose levels, Blood cultures
  • IV Antibiotics as per Trust guidelines (may be under section for Necrotising fasciitis)
  • Urethral catheter- this will help with monitoring urine output and help identify the urethra during the operation.
• Overall Management
  • Surgical debridement
    • Will need NCEPOD list and on call anaesthetic contacted
    • ITU referral for aftercare
  • Patient will require a relook operation in 48 hours, which may involve further debridement
  • General surgery input will be required in extensive cases for consideration of “defunctioning colostomy”, to avoid further soiling of the affected area.
  • Tissue viability nurses’ input regarding ongoing dressing care
  • Plastic surgery input will be needed for consideration of skin grafting, once the infection has been treated and the patient stabilised.

Torsion of the hydatid of Morgagni

• The hydatid of Morgagni is an embryological remnant of the Mullerian duct normally on the upper pole of the testis.
• This can twist causing a sudden onset of scrotal pain.
• On examination the pain will be focal, the duration can be longer and there can be a blue dot present on the scrotum.
• Normally identified on scrotal exploration (being performed for presumed torsion) as ultrasound is not always diagnostic.
• Hydatid of Morgagni torsion is self-limiting and has no long-term impact. It can be managed simply with analgesia. 

Varicocele

• Dilatation of the pampiniform plexus of the scrotum, normally on one side
• Will be more pronounced when patient standing up.
• Due to thermoregulation being altered, varicocele can affect fertility
• In men with left sided varicocele an abdominal scan is required to rule out a left sided renal mass occluding the drainage of the left testicle into the left renal vein.

Hydrocele

• Collection of fluid in the scrotum
• Due to patent processus vaginalis in infancy.
• At other times due to abnormal fluid dynamics within the tunica vaginalis, where absorption is delayed. It can also occur secondary to tumour, trauma or infection.
• Will be associated with a fluctuant scrotum that easily transilluminates
• Can spontaneously resolve but may require elective surgical intervention if affects the patient quality of life.

Epididymal Cyst

• Simple cysts forming in the epididymal region
• Normally asymptomatic but if large can cause discomfort due to mass effect from cyst size.
• Can be self-limiting and self-resolving but may require elective surgical intervention if affecting the patient’s quality of life.

Testicular Trauma

• Uncommon presentation to hospital and rarely will require intervention
• Can occur secondary to inguinoscrotal surgery
• Categorised as either Blunt or Penetrating trauma
• Basic assessment involves (8):
  • Assessment for other injuries as per ATLS guidelines
  • Resuscitation and stabilisation of the patient
  • Optimise analgesia
  • Assessment of the whole external genitalia (penis, perineum, urethra)
  • Assessment of the swelling
• In Blunt injury an urgent ultrasound with Doppler is recommended (8)
  • If the tunica albuginea is intact and no haematoma is present, then no intervention is required
  • If a small haematoma is present but the tunica albuginea is in tact then the patient will require conservative management involving scrotal support and analgesia and repeat imaging in 28 hours
  • If a large or expanding haematoma or disruption to the tunica albuginea is present, then exploration and surgical repair is indicated
• All penetrating injuries require exploratory surgery along with tetanus booster (if uncertainty regarding tetanus status) and broad-spectrum antibiotics.

References

References

1. Partin, A.W., Peters, C., Kavoussi, L.R., Dmochowski, R.R., Campbell, M.F., Walsh, P.C. and Wein, A.J. (2021). Campbell-Walsh-Wein handbook of urology. Amsterdam: Elsevier.
2. Fahmy, M.A.B. (2022). Anatomy of the Scrotum. In: Fahmy, M.A.B. (eds) Normal and Abnormal Scrotum. Springer, Cham. https://doi.org/10.1007/978-3-030-83305-3_8
3. Jones, O. (2014). The Testes and Epididymus – Structure – Vasculature -TeachMeAnatomy. [online] Teachmeanatomy.info. Available at: https://teachmeanatomy.info/pelvis/the-male-reproductive-system/testes-epididymis/.
4. Clement, K.D., Light, A., Asif, A., Chan, V.W.-S., Khadhouri, S., Shah, T.T., Banks, F., Dorkin, T., Driver, C.P., During, V., Fraser, N., Johnston, M.J., Lucky, M., Modgil, V., Muneer, A., Parnham, A., Pearce, I., Shabbir, M., Shenoy, M., Summerton, D.J., Undre, S., Williams, A., MacLennan, S., Kasivisvanathan, V. and (2022), A BURST-BAUS consensus document for best practice in the conduct of scrotal exploration for suspected testicular torsion: the Finding Consensus for Orchidopexy in Torsion (FIX-IT) study. BJU Int, 130: 662-670. https://doi.org/10.1111/bju.15818)
5. Barbosa JABA, de Freitas PFS, Carvalho SAD, Coelho AQ, Yorioka MAW, Pereira MWA, Borges LL, Srougi M, Nahas WC, Arap MA. Validation of the TWIST score for testicular torsion in adults. Int Urol Nephrol. 2021 Jan;53(1):7-11. doi: 10.1007/s11255-020-02618-4. Epub 2020 Aug 25. PMID: 32844355.

• Mellick LB, Sinex JE, Gibson RW, Mears K. A Systematic Review of Testicle Survival Time After a Torsion Event. Pediatr Emerg Care. 2019 Dec;35(12):821-825. doi: 10.1097/PEC.0000000000001287. PMID: 28953100.

• Eke, Ndubuisi & Raphael, John. (2011). Fournier’s Gangrene. 10.5772/24293.

• Lucky M, Brown G, Dorkin T, Pearcy R, Shabbir M, Shukla CJ, Rees RW, Summerton DJ, Muneer A; BAUS Section of Andrology and Genitourethral Surgery (AGUS). British Association of Urological Surgeons (BAUS) consensus document for the management of male genital emergencies – testicular trauma. BJU Int. 2018 Jun;121(6):840-844. doi: 10.1111/bju.14163. Epub 2018 Apr 10. PMID: 29635819.

Written by Saurabh Verma (Clinical Fellow, James Paget University Hospital GMC: 7560241)

Verified by: Mohamed K. E. Mustafa (ST3, Lincoln County Hospital, GMC: 7590727) & Mohamed Elajnaf (ST4, Ipswich Hospital, GMC: 7649193)