The Acute Scrotum – Expedited Diagnosis Using The TWIST Rule From Pediatric EM Morsels With Additional Resources

What follows are excerpts from Dr. Fox’s Testicular Workup for Ischemia and Suspected Torsion (TWIST) Score: from Pediatric EM Morsels – “Pediatric Emergency Medicine Education”.*

*Pediatric EM Morsels is for me the most outstanding pediatric FOAM site. I will go there on my smart phone whenenever I have five or ten minutes. Awesome!

Note to myself: When reviewing Dr. Fox’s TWIST post, be sure to review all of his other posts on the acute scrotum that he links to in the TWIST post.

All that follows is from Dr. Fox’s post on TWIST:

Recently, I learned a new phrase that can help me clearly communicate with our Urology colleagues when dealing with children presenting with acute scrotal pain. Let’s make sure we speak clearly – Testicular Workup for Ischemic and Suspected Torsion (TWIST):

Testicular Torsion: Basics

  • Testicular Torsion has 2 peaks of incidence: one peak during 1st year of life and another from 12-18 yrs.
  • Classic presentation is of:
    • Acute, unilateral testicular pain with,
    • Nausea and vomiting
    • Absent cremasteric reflex* on affected side
    • Swelling and tenderness
    • Abnormal testicular position

*See also YouTube Videos On The Physical Exam And Ultrasound Exam of The Testes
Posted on January 7, 2020 by Tom Wade MD

  • Unfortunately, nothing is that simple, and classic is not common.
    • Cases of testicular torsion have occurred in which each finding has been violated, including having had torsion in the presence of normal cremasteric reflexes.
    • Intermittent Torsion (Torsion – Detorsion) does occur –
      • Can lead to confounding presentations and even “fool” ultrasound.
      • 50% of patients diagnosed with torsion have had a prior episode of intermittent torsion that had spontaneous resolution.

Testicular Torsion: The Dilemma

  • There are several factors in this equation:
    • Time is critical.
    • Testicular torsion is less common than other causes of acute scrotal pain.
    • No single historic or exam feature can reliably rule in or rule out the condition.
    • Ultrasound is often requested to further assist with clarity.
    • Ultrasound takes time (although, another great reason to improve your use of bedside ultrasound – that can be another New Year’s Resolution).
  • A possible way to improve clarity of communication has recently been advocated for – The TWIST Score

Testicular Torsion: TWIST Score

  • Testicular Workup for Ischemic and Suspected Torsion (TWIST) Score was developed by Urologist, validated with non-physician triage, and recently tested in tertiary Pediatric ED with physician providers utilizing it. [Frohlich, 2017; Sheth, 2016; Brunhara, 2016]
  • TWIST Score is a Summation of 5 Clinical Variable:
    • Presence of Testicular Swelling = 2 points
    • Presence of Hard Testicle = 2 points
    • Absence of Cremasteric Reflex = 1 point
    • Presence of High Riding Testicle = 1 point
    • Presence of Nausea/Vomiting = 1 point
  • Scores, Risk, and Proposed Management [Frohlich, 2017; Sheth, 2016; Brunhara, 2016]
    • High Risk = Score of 6 or 7
      • NO imaging.
      • Consider imaging those children who are Tanner Stage 1-2 (who had more confounded exams) – some advocate for only using TWIST Score in pubertal males.
      • Convey this high risk score and help expedite surgical exploration with your Urology colleagues.
    • Intermediate Risk = Scores of 1-5
      • Obtain scrotal ultrasound 
      • Consider alternative diagnoses (ex, Epididymitis) and obtain additional testing as warranted (ex, U/A, STD screen)
    • “Low” Risk = Scores of 0
      • In original paper, “Low Risk” was not associated with Torsion and avoiding ultrasound in this group was advocated for…. but, as was mentioned above, Torsion can be deceptive and present atypically… so I would still have a low threshold for obtaining an ultrasound.
      • Alternative diagnosis is more likely, though, so consider the rest of the DDx as well (ex, EpididymitisVaricocelesUTINephrolithiasisMumpsHSP).

Moral of the Morsel

  • Don’t Get it TWISTed! Know the TWIST Score and communicate it clearly to your Urology colleagues, but know that it is not perfect and your H+P and clinical acumen need to be “calculated” as well.
  • Coordinate with your Urology Colleagues Early. For time sensitive conditions, particularly ones that may lead to early activation of an OR, develop strategies and protocols even before the patient has arrived!

For more information on the Acute Scrotum, see the resources below.


(1) Testicular Workup for Ischemia and Suspected Torsion (TWIST) Score

(2) The Acute Scrotum [Link To Download the PDF]. © 2012, 2016 American Urological Association Education and Research, Inc.® All Rights Reserved

(3) Acute Onset of Scrotal Pain-Without Trauma, Without Antecedent Mass ACR Appropriateness Criteria. Revised 2018.

(4) Emergency Department Approach to Testicular Torsion: Two Illustrative Cases [PubMed Abstract] [Full Text HTML] [Full Text PDF]. Cureus. 2019 Oct 22;11(10):e5967. doi: 10.7759/cureus.5967.

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