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Injectable Orange Editorial: In the second installment of Chris Picard’s series of Nurse-oriented, evidence-based assessment skills, he dives into the assessment of cremasteric reflex for testicular injury. While it is not the role of the nurse to diagnose, understanding of assessment techniques and rationale add to the ability to communicate within the multi-disciplinary team. Chris continues to explore the disconnect in nursing when it comes to owning physical assesment skills. Check out Chris’ site http://foaned.blogspot.ca/
Editorial Addition, 31st July: Ross Fisher, Consultant Paediatric Surgeon from Sheffield in the UK, thoughtfully commented on this post and provided a definite reminder as to the context of all assessment being vital. Thanks Ross for contributing tacit experience into the discussion:
I’d be cautious about using the cremasteric reflex, particularly in children, as an assessment tool. In little ones, the reflex can be so sensitive as to pull the testis very high on simple contact of the examining hand, suggesting “loss” of the reflex to the unexperienced. In acute idiopathic scrotal oedema the scrotum can already be thickened and obscure visualisation. A testis may torse and then detorse and still have the reflex intact.
Our teaching is that INFERIOR pole tenderness of a testis is exceptionally unlikely to be torsion of the appendix testis or epididymitis ie very highly likely to be testicular torsion.
The cremasteric reflex is a superficial reflex that can be exceptionally useful in assessing testicular emergencies.
The cremasteric reflex is a contraction of the cremaster muscle, in response to the stroking of the thigh, which results in retraction of the testicle. Absence of the reflex is an ominous sign when assessing an acute scrotum.
When assessing an acute scrotum, the most important condition to rule out is testicular torsion (Ringdahl & Teague 2006). Testicular torsion occurs when the testicle rotates within the scrotum, the twisting out the epididymis results in impaired blood flow, ischemia can ensue rapidly, and can eventually result in loss of the testicle (Ringdahl & Teague 2006).
Testicular torsion usually occurs in the absence of trauma, and without precipitating factors; although an abnormal attachment of the testicle to the scrotum “bell clapper” deformity, present in approximately 10% of males, puts an individual at increased risk. The overall incidence of testicular torsion is estimated at 1 per 4000 in males under age 25, with the highest incidence occurring during the first few days of life, and from age 12-18yrs. (EBMedicine, Ringdahl & Teague 2006). Testicular torsion requires emergency urology referral, as ischemia begins within 4 hours (Ringdahl & Teague 2006). It is precisely for this reason that knowing how to assess for a cremasteric reflex is essential.
When assessing an acute scrotum for testicular torsion one testicle may appear to be shortened due to the twisting of the epididymis, cremasteric reflex may be absent on this side, but the test should be performed bilaterally. To assess cremasteric reflex the thigh should be stroked with a finger, the handle of a reflex hammer, or most commonly with the blade of a tongue depressor. A normal finding is a retraction of at least 0.5 cm; an abnormal, or absent reflex needs immediate referral.
The cremasteric reflex, in the presence of scrotal pain has been estimated at 96-99% sensitive (Ringdahl & Teague 2006, Schmitz & Safranek, 2009); which is to say that the probability of having a false negative is approaching zero percent. Absent reflex is 66-88% specific for torsion, yielding a negative predictive value of 96% (EBMedicine). The caveat to these probabilities is that an absent cremasteric reflex can be considered normal in approximately 50% of infants under the age of 30 months (Ringdahl & Teague 2006). The importance of the high sensitivity from the nursing perspective is that we can be relatively certain that the odds of a false negative are low, and that there will likely be need for urgent referral of these patients.
Correction, or de-torsion of a testicle, can be performed manually with local or procedural sedation; however it is generally addressed through emergent surgical exploration and intervention. Salvage rates are time dependent: surgery within six hours is 90% successful in salvaging the testicle, successful salvage drops to 50% by hour 12, and less than 10% after 24 hours (Ringdahl & Teague 2006). For this reason there is a low threshold for referral and diagnostic studies.
As a nurse knowing how to assess cremasteric reflexes can be exceptionally useful because, in the presence of scrotal pain, an absent creamasteric reflex approaches 100% sensitivity for testicular torsion. Given the short window for surgical intervention, the risks of over-triage, or over treatment due to a false positives are far outweighed by the potential benefit that patients with testicular torsion will experience from rapid referral and intervention.
The cremasteric reflex is a low barrier, easily performed physical assessment. It is a highly sensitive screening tool for patients who need immediate physician attention and surgical referral.
References
Ringdahl, E., & Teague, L. (2006). Testicular Torsion. American Family Physician, 74(10).
EB Medicine Topics (EB Medicine Topics)., http://www.ebmedicine.net/topics.php?paction=showTopicSeg&topic_id=113&seg_id=2275
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I’d be cautious about using the cremasteric reflex, particularly in children, as an assessment tool. In little ones the reflex can be so sensitive as to pull the testis very high on simple contact of the examining hand suggesting “loss” of the reflex to the unexperienced. In acute idiopathic scrotal oedema the scrotum can already be thickened and obscure visualisation. A testis may torse and then detorse and still have the reflex intact.
Our teaching is that INFERIOR pole tenderness of a testis is exceptionally unlikely to be torsion of the appendix testis or epididymitis ie very highly likely to be testicular torsion.
Thanks for posting this
It is an interesting post – very important to be reminded about cremasteric reflex as we often get bogged down on the necessity of ‘high triage categories’ and the ‘CRM minefield’ of escalating these cases to the urologists who sometimes think Ultrasound can rule or rule out a torsion.
I was a bit confused about this sentence: “The importance of the high sensitivity from the nursing perspective is that we can be relatively certain that the odds of a false negative are low, and that there will likely be need for urgent referral of these patients.”
Usually if an exam sign or test is “sensitive” it’s good for ruling out, so normally this would decrease your urgency to call / escalate the case urgently. The absence of cremasteric reflex while not specific for torsion (as you said) would be useful information. Having said this, if it’s an acute testicle my thoughts would be that a good ED assessment followed by referral on is important due to the risk of the ‘big miss’ in the acute testicle. Caution advised here.
The article by Ringhdal you quoted itself quotes this paper http://www.ncbi.nlm.nih.gov/pubmed/2769854 which shows patients under 18 get a delayed diagnosis. The difficulty obtaining a good physical exam may contribute but it could also be that lots of kids present with a ‘difficult history’ and are triaged as abdminal pain. This is a strong argument for testicular exam in boys under 18 with abdominal pain.
This sentence may also need clarifying/expansion: “Absent reflex is 66-88% specific for torsion, yielding a negative predictive value of 96%” – I think you calculate NPV by using the True and False Negative (not the positives) so it’s not really related so much the specificity of the test which looks at False Positive and True Negatives. (https://www.medcalc.org/calc/diagnostic_test.php)
Just my (non expert) two cents on this difficult area
A
Thanks for the comments Andrew,
I was having some difficulty in balancing clarity with brevity in this post. I think that you have mentioned some points that are worth further discussion: You had raised a concern about the statement:
“The importance of the high sensitivity from the nursing perspective is that we can be relatively certain that the odds of a false negative are low, and that there will likely be need for urgent referral of these patients.”
and discussed how high sensitivity tests are useful to rule out conditions. This sentiment is generally true: a highly sensitive test (that is negative) is indeed a good way of ruling out a condition (SN-N-Out). However in this example, a positive finding, I find it easier to think of sensitivity as the “true positive rate”. A high sensitivity (high true positive rate) test has a low likelihood for false negative, which is why increasing index of suspicion is warranted. Therefore from a nursing (non-diagnosing) perspective increasing triage (ruling in) score based on absent cremasteric reflex is justifiable, and makes the reflex a useful tool.
What you said about calculating NPV is correct: it can certainly be performed using true and false negative rates; however, it can also be calculated using sensitivity, specificity and prevalence. I mentioned the sensitivity and specificity values but didn’t specify prevalence as it will vary by patient group.
I think your idea of performing testicular exams in patients <18y/o to avoid mis-categorization as abdominal pain is interesting. I would be hesitant to extend the sensitivity/specificity of the cremasteric reflex to these patients without knowing the prevalence (pre-test probability) of torsion in this population; but I think the sentiment of suspecting testicular emergency in pediatric abdominal pain is a good one.
I would also like to thank you for mentioning that referral is important. I would like to stress that what I present is an argument for the urgent referral of patients with testicular pain and absent cremasteric reflex, it is in no way an endorsement of the non-referral of testicular pain with normal cremasteric reflex.
I was having some difficulty in balancing clarity with brevity in this post; I apologize if I've sacrificed one in favour of the other. Thank you for your comments, insights, and contribution to peer learning.
Chris