Does specificity of electrodiagnostic test referrals predict test outcome in children?

Abstract

Introduction/Aims: Electrodiagnostic testing (EDX) is important in evaluation of pediatric neuromuscular disease. Non-specific referrals have emerged as a leading reason for EDX in recent years. We examine whether referral-specificity is predictive of test outcomes in children.Methods: EDX referrals and outcomes were audited over a 7-year period from 2013 to 2020 at CHI-Crumlin. Pre-test details were coded and compared to EDX outcomes using multinomial logistic regression.Results: EDX studies were performed in 702 children (median age 10.2 years). In 36% of patients, EDX-referrals did not specify any pre-test diagnosis. Mononeuropathy (24%) and polyneuropathy (15%) were the leading pre-specified diagnoses as well as the most common test outcomes. Neurology and orthopedics/plastic surgery contributed the majority of referrals. Metabolic medicine and hematology/oncology were most likely to pre-specify a working diagnosis and were the specialties with both the highest proportion of abnormal outcomes and referral accuracy. EDX abnormality was present in 42% of patients and was predicted by specificity of referral and the absence of pain as a leading symptom. The accuracy of specified pre-test diagnoses was highest for suspected anterior horn cell disorders (67%). Accuracy of referrals, as well as abnormal test outcomes, were negatively predicted by the presence of pain as a leading symptom.Discussion: EDX is informative in children but the likelihood of abnormal testoutcomes is diminished when a pre-specified working diagnosis is lacking or when the primary reason for referral is pain.

Pins and needles: The neurological examination and electrodiagnosis in children

“…In this issue of the Journal, McHugh et al 5 provide a response to such existential questions for the pediatric neuromuscular community. By retrospectively auditing 702 children attending the pediatric EDx laboratory at a single tertiary referral center in Ireland and matching their documented pretest diagnosis with the results of their EDx study, they concluded that pediatric EDx testing remains useful and is likely to identify an abnormality in patients referred with a specific working diagnosis.…”

“…McHugh and colleagues 5 remind us that the EDx laboratory is the perfect setting for exercising the neurologistʼs most vaunted skill‐‐‐that of history and clinical examination, 18 and subsequently merging it with EDx prowess 7 . In other words, it is an idyllic venue for graceful pirouettes of the neurological pin under the melodic sounds recorded by the EMG needle.…”

“…Pain, for example, the main reason for inappropriate EDx referral in this study, 5 is a psychological or physiological phenomenon produced by many structures beyond the nervous system, although it can be the hallmark of frank neuromuscular disorders such as pediatric Guillain-Barré syndrome. 20 McHugh and colleagues 5 remind us that the EDx laboratory is the perfect setting for exercising the neurologistʼs most vaunted skill--that of history and clinical examination, 18 and subsequently merging it with EDx prowess. 7 In other words, it is an idyllic venue for graceful pirouettes of the neurological pin under the melodic sounds recorded by the EMG needle.…”

“…From a clinical standpoint, it can be done merely by returning to our Bayesian grassroots as physicians, 19 making history-taking and clinical examination the cornerstone of our evaluation, and re-establishing the traditional perspective of seeing the forest and not just the trees, despite the increased trend toward subspecialization. Pain, for example, the main reason for inappropriate EDx referral in this study, 5 is a psychological or physiological phenomenon produced by many structures beyond the nervous system, although it can be the hallmark of frank neuromuscular disorders such as pediatric Guillain-Barré syndrome. 20 McHugh and colleagues 5 remind us that the EDx laboratory is the perfect setting for exercising the neurologistʼs most vaunted skill--that of history and clinical examination, 18 and subsequently merging it with EDx prowess.…”

“…4 In that ever-changing landscape, one naturally wonders what role traditional approaches of clinical examination and EDx testing still play? 2 In this issue of the Journal, McHugh et al 5 On the other hand, there are several limitations, most of which were already acknowledged by the authors. First, generalizability is challenged by local practice patterns.…”