Common presentation of Testicular Torsion
•Acute pain
- Can be intermittent due to detorsion phenomenom
- Not relieved by elevation
•Swelling
•Vomiting
On exam:
•Enlargement and oedema of affected testis
•Absence of cresmasteric reflex
•Abnormal lie of testis
- Transverse lie
- Anterior rotation
However presentation and exam is similar to epididymo-orchitis without fever or urethral discharge which can make clinical diagnosis challenging.
Majority of torsions occur spontaneously with only 5-8% post traumatic,
typically minor trauma.
Types of torsion:
Anatomically there are two different types of torsion which are age-dependent
Extravaginal
- Neonates
- Torsion occurs at level of external inguinal ring
Intravaginal
- Adolescents and young men
- Classically associated with Bell Clapper deformity
Fig. 1: Bellclapper Deformity
Bell Clapper deformity= Congenital anomaly where tunica vaginalis inserts high on spermatic cord allowing the testis to rotate.
Pathophysiology:
Spermatic cord torsion leads to
- Initially obstruction to venous outflow (<180° rotation)
- Then increased intratesticular pressure and resistance
- Finally obstruction to arterial inflow and ischaemia (>180° rotation)
Tissue viability determined by
- Number of rotations:180° - 720°
- Duration of ischaemia
At:
- 4-6 hours: Viability likely,
almost 100% salvage rate
- 6-12 hours: Ischaemia and irreversible testicle damage likely,
approximately 80% salvage rate
- >12 hours: Necrosis likely,
20% salvage rate
Ultrasound signs of testicular torsion:
1.
Twisting of the Spermatic Cord:
Likely the most specific and sensitive finding in both complete and incomplete torsion.
Fig. 2: Whirlpool Sign
Dynamic downward movement of transducer leading to ‘Whirlpool sign’ with absent flow distal to whirlpool on Doppler imaging.
2.
Alteration of blood flow:
Evaluation for testicular torsion by colour Doppler ultrasound has a reported sensitivity of 82% and specificity of 100%
- But 10% of early/partial torsions have normal ultrasound exams
Incomplete torsion
- Elevated resistive index (RI > 0.75)
- To and fro flow/Loss of normal low diastolic arterial flow
Fig. 3: Flow abnormality
Complete torsion:
Absence of blood flow in both the testis and epididymis
- 100% sensitivity for torsion when present
Fig. 4: Complete loss of flow
Increased Size:
Alterations in size of testis and epididymis of affected side.
- Less specific and can be seen commonly in epididymo-orchitis
Alteration of Parenchyma:
Homogeneous echotexture
- Early finding occuring before necrosis
Heterogeneous echotexture
- Late finding > 24hours
- Hypoechoic regions represent necrosis with hyperechoic regions represent haemorrhage and congestion.
- Peripheral testicular neovascularisation seen >days represents recruiting and enlargement of small peripheral collaterals
Fig. 5: Alteration of parenchyma
Fig. 6: Alteration of parenchyma
Associated signs:
Fig. 7: Reactive hydrocoele with thickening of epididymis.
- Reactive hydrocoele
- Thickening of overlying scrotal skin
But non specific,
can be seen commonly in epididymo-orchitis.