TWIST Score for Testicular Torsion

I recently came across a risk stratification tool for testicular torsion called the TWIST (Testicular Workup for Ischemia and Suspected Torsion) Score. I am sharing more information regarding its purpose, scoring, validity, and utility in the emergency department for patients with acute testicular pain. 

TWIST (Testicular Workup for Ischemia and Suspected Torsion) Score

Testicular Torsion

- Testicular torsion is a surgical emergency and requires prompt intervention (time = testicle, people)

- It is a clinical diagnosis and definitive management can be delayed by testicular ultrasound, especially in lower resource settings 

Purpose 

- The TWIST score was originally developed by urologist Dr. Barbosa at the Clinical Hospital of the University of Sao Paolo in Sao Paolo, Brazil

- It was created to: 

      - Risk stratify for testicular torsion in children with acute scrotal pain

      - Reduce the need for testicular ultrasound, ultimately reducing delay to definitive management (OR) in patients with true testicular torsion 

Scoring (MD Calc) 

Validity

- In pediatrics: A prospective study published by the Society for Academic Emergency Medicine in 2021 examined the validity of the TWIST Score when utilized by pediatric emergency medicine providers. Males age 3 months to 18 years old were included (N=258, 19 diagnosed with testicular torsion). A high-risk TWIST score (7) was found to have 100% specificity and 100% positive predictive value for testicular torsion. 

- In adults: A prospective study published by the creator of the TWIST Score in 2021 examined the validity of the TWIST score when used by non-expert providers (aka non-urologists) in adults. Males who presented to a tertiary care hospital were included (N=68, 34 diagnosed with testicular torsion). A TWIST score of 5 (high risk) showed a positive predictive value of 90%, and a TWIST score of 6-7 (high risk) had a positive predictive value of 100%. A TWIST score of <2 (low risk) had 100% negative predictive value. 

- A Systematic Review / Meta-Analysis published in 2022 compared various studies (adult and pediatric patients included) analyzing different testicular torsion risk stratification scores (N=1060, 199 diagnosed with testicular torsion). It demonstrated a sensitivity of 98% in low risk patients (TWIST score 0-2) and a specificity of 97% in high risk patients (TWIST score 5-7). Per 100 acute scrotum patients, there was a 1.6/100 missed torsion rate with the TWIST score. The study found that the TWIST score is the most reliable current risk stratification tool for testicular torsion and effective for widespread adoption. 

Utility of the TWIST Score in the emergency department 

- The TWIST score is a validated and reliable tool for risk stratifying for testicular torsion in adult and pediatric patients with acute scrotal pain 

- In high-resource settings, the TWIST score may be useful to advocate for immediate urologic evaluation and definitive management as opposed to waiting for a testicular ultrasound, as delay may result in permanent testicular damage and fertility issues 

- In low-resource settings, the TWIST score may be useful for the following scenarios (i.e freestanding ED / ultrasound is unavailable / urologic consultation is unavailable): 

           - Expedite decision-making regarding whether or not to transfer a patient out for urologic evaluation 

           - Guide decision-making when clinical findings are equivocal on whether or not to obtain or transfer for a testicular ultrasound

- Institution-specific protocols exist for testicular torsion and should be followed

- Always err on the side of caution. Remember, time = testicle!  

High Sensitivity Troponin

Today I will be discussing the high sensitivity troponin test for diagnosing acute coronary syndrome in the emergency department. Many emergency departments nationwide (and worldwide) have transitioned towards using high-sensitivity troponins. It is crucial to understand the test, benefits compared to standard troponin, use, and interpretation. 

High Sensitivity Troponin vs. Standard Troponin for Detection of ACS 

• High sensitivity troponin recommended by the American College of Cardiology (ACC) in 2022 as gold standard for use in diagnosing ACS in the emergency department. Plethora of evidence demonstrating high sensitivity troponin's ability to detect:

  • A greater number of MIs within 30 days (without change in mortality rate)  

  • Lower concentrations of troponin compared to standard troponin (mild/subclinical injury)  

  • ACS earlier in course, often 1-3 hours after myocardial injury

Use of High Sensitivity Troponin in the ED 

• Recommended use in patients with symptoms concerning for ACS in the ED: 

1. Obtain high-sensitivity troponin

2. rapid rule-out of ACS with a non-ischemic ECG and either 1) one very low troponin result (depending on onset time of chest pain >3hrs) OR 2) very low change between two consecutive troponins (aka low delta troponin) 

• Below is an algorithm from Ali-EM for recommended use. Troponins are recommended by the AHA/ACC to be trended every 3 hours, if trending is clinically indicated. Protocols are institution-specific.  

Interpretation of High-Sensitivity Troponin

• Normal values vary based on type of high sensitivity troponin (institution-specific) and sex: 

  • High Sensitivity Troponin I (hs-TnI) Males: <20 ng/L and Females: <15 ng/L 

  • High Sensitivity Troponin T (hs-TnT) Males: <14 ng/L and Females: <9 ng/L

• Limitations 

  • Because high sensitivity troponin tests detect lower troponin levels, there are more likely to be false positives for ACS detection (especially in chronic illness / stress / stable CAD / HF / CKD). This may result in unnecessary testing and invasive measures. Further clinical trials are required to guide clinical-decision making in these situations. Troponins should only be ordered when clinically relevant, and should be carefully interpreted based on clinical context. 

VOTW: What did the lung say to the liver? We be-lung together!

Hello all! This week’s VOTW is brought to you by yours truly!

Hospital course

8 y/o M with PMH asthma presented after 5 days of URI-like symptoms with worsening shortness of breath yesterday. On exam the patient was tachycardic and had active subcostal retractions and crackles on auscultation. A bedside thoracic ultrasound was done.

Ultrasound

Shown above is the right hemidiaphragm or right upper quadrant view. We can see the liver and lung with the diaphragm (dotted line) in between. Note that the lung looks very similar in appearance to the liver! This liver-like appearance of the lung is called ‘hepatization’.

In the image above the lung contains small, dark linear structures that are called air bronchograms. They represent air-filled bronchi.

Case Conclusion

The patient continued to have respiratory distress and developed status asthmaticus requiring PPV. CXR showed bilateral atelectasis and possible underlying airspace disease concerning for pneumonia. The patient was admitted to the PICU on HFNC and given asthma treatments and IV antibiotics.  

Lung hepatization & air bronchograms

·       This patient had a combination of both lung atelectasis and pneumonia. Typically, lung tissue is not visible on ultrasound considering that it is normally filled with air. However, in the case of pneumonia, alveoli are filled with inflammatory fluid creating consolidations, while in the case of atelectasis the alveoli are collapsed rather than fluid filled. This pathologic lung tissue is now visible with ultrasound!

·       Lung consolidations change the appearance of lung tissue on ultrasound such that its echogenicity looks remarkably liver-like, termed ‘hepatization’. This can also be seen in atelectasis.

·       Air bronchograms visible on ultrasound represent air trapped within the small bronchi which are surrounded by lung tissue. Static air bronchograms are mostly seen in compression atelectasis but can also be seen in pneumonia; they are hyperechoic air-filled bronchi that do not move with respirations. Dynamic air bronchograms are pathognomonic for pneumonia; they represent air bubbles moving through fluid filled lung tissue. On ultrasound, dynamic air bronchograms look like numerous hyperechoic opacities that move with respirations.

Happy scanning!                                                                              

Sono team

Resources to review:

·       https://www.acep.org/sonoguide/basic/lung

·       https://coreultrasound.com/5msblog-dab/

·       https://www.thepocusatlas.com/lung/