Common Tests May Miss Pediatric Diabetic Neuropathy

Marlene Busko

April 11, 2014

Noninvasive methods for screening pediatric patients with type 1 diabetes for peripheral diabetic neuropathy (DN) have low sensitivity, according to a systematic review published online April 7 in Pediatrics.

The American Diabetes Association recommends that starting in puberty, children with type 1 diabetes undergo annual screening for DN using a 10-g monofilament to see whether the patient detects light touch. However, the authors found that neither this method nor screening with a tuning fork was terribly useful for detecting DN.

"It is important to stress the scarcity of data on this subject," the review's lead author Gerrit Hirschfeld, PhD, from the German Pediatric Pain Centre, at Children's and Adolescents' Hospital Datteln, in Germany, told Medscape Medical News in an email. "We were able to identify only 5 studies [of noninvasive tests], and several suffered from severe methodological problems.

"Pediatricians should continue to screen for DN with the best method available to them," Dr. Hirschfeld advised. "If this entails a 10-g monofilament and tuning fork, they should keep in mind that these probably detect only stronger forms of nerve damage compared with more sensitive [noninvasive] methods (1-g monofilaments or biothesiometry)." Even these 2 latter tests are not without issue, however. They look promising, but more work is needed in a pediatric population to confirm the robustness of early findings and to establish normal ranges for different ages.

Diagnostic Utility of Pediatric DN Screening Methods

Although children with peripheral neuropathy often have no pain, they are at increased risk of developing severe complications such as foot ulcers, Dr. Hirschfeld explained. About 25% to 50% of children who have diabetes for more than 5 years have decreased nerve function, according to earlier research.

Therefore, national and international guidelines recommend annual screening for DN, although they differ slightly in recommended methods (monofilament, biothesiometer, or tuning fork) and indications (from what age or diabetes duration onward). In the United States, an estimated 215,000 children and adolescents have diabetes, and every day several hundred of them are tested for DN.

Nerve-conduction–velocity studies (the gold standard) are painful and not available to all pediatricians. The noninvasive Semmes-Weinstein monofilament test and Rydel-Seiffer tuning fork test are the most commonly used screening methods.

To better understand the diagnostic usefulness of the different noninvasive screening, the authors searched the literature and identified 5 studies that examined vibration-detection tests, including 2 that also looked at sensitivity to touch. The studies were too heterogeneous to perform a meta-analysis.

In 2 studies, the biothesiometer device had acceptable sensitivity (61%, 80%) and specificity (64%, 76%) to detect DN. In 3 studies, the tuning-fork test was very sensitive (87%, 98%, 99%), but not specific at all (1%, 3%, 19%). In the 1 study that screened for DN by using a fine monofilament, diagnostic accuracy was acceptable (sensitivity, 73%; specificity, 87%). In 1 study where a coarse monofilament was used to detect DN, test sensitivity (16%) and specificity (64%) were not acceptable.

Reasons for the notable lack of studies of the diagnostic utility of screening procedures may be the mistaken belief that findings from studies in adults can be transferred to children, or because, if DN is detected, there is no cure, the authors speculate.

Even though "at present no specific interventions exist that could reverse the underlying nerve damage…existing treatment strategies and foremost, glycemic control, are essential for avoiding further damage," Dr. Hirschfeld observed. "We are currently testing the utility of the 1-g monofilament [and]...I hope that our review will stimulate further research into this issue," he said.

More Studies Needed in Children

Asked to comment, Maria Louraki, MD, from the University of Athens and the Panagiotis & Aglaia Kyriakou Children's Hospital, Greece, observed in an email that "the present systematic review revealed that despite the widespread use of screening methods for DN…many children with type 1 diabetes and early DN may not be diagnosed promptly due to the low sensitivity and specificity of the used diagnostic tools."

In the future, in screening for pediatric DN, "the 10-g monofilament may be replaced by finer monofilaments (1 g) or by biothesiometry, the latter being widely available and easy to use by pediatric diabetologists," she added. However, like Dr. Hirschfeld, she notes that "due to the lack of age-related normal ranges for…monofilaments and biothesiometry, before the relevant guidelines change, relative studies on children and adolescents should be performed to define [normal ranges] in this age group."

The authors have reported no relevant financial relationships. The study was supported by a German Research Foundation grant.

Pediatrics. Published online April 7, 2014. Abstract


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