Normative Observational Nerve Ultrasound Values in School-Age Children and Adolescents and Their Application to Hereditary Neuropathies

Abstract

Backgrounds: We have aimed to establish nerve ultrasound reference data in 8 to 17year-old children and adolescents and to compare those data to younger children, adults, and age-matched children with polyneuropathies. Methods: High-resolution ultrasounds of the nerves were performed in 117 healthy children and adolescents at 20 predefined landmarks in the neck and the extremities of both sides. Mean values, side-to-side differences and intraneural ratios, as well as upper limits have been calculated. In a second step, a comparison between 25 children and adolescents of the same age range with proven hereditary and acquired neuropathies and lysosomal storage diseases has been carried out. Results: Nerve growth correlates significantly with age and reaches adult values at the age of around 15 years. The influence of body mass index and gender is negligible at most segments. By the use of age-specific upper limits, nerve enlargement could be seen in distinct types of neuropathies, particularly in demyelinating hereditary and inflammatory types, which is comparable to findings in adults, but also in rare lysosomal storage diseases. Conclusion: Nerve size correlates with age during childhood and reaches a climax in younger adults. Age-matched reference data are inevitable to differ between hypertrophic and non-hypertrophic nerve damage, e.g., in neuropathies.

Nerve Ultrasound as Helpful Tool in Polyneuropathies

“…Another important point is to establish a scanning protocol, which includes the nerve and its measure points. Several analyzing protocols have been published so far [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 27 ]. Unfortunately, common protocols or guidelines (as in nerve conduction studies) do not exist so far [ 6 ].…”

“…The most intriguing nerve enlargement can be found in patients with Charcot Marie Tooth (CMT) type 1 (CMT1) neuropathies, particularly type A [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. Most of these patients (88–100%) exhibit a generalized nerve enlargement present at all sites with at least one region showing a CSA more than twice of the upper normal limit ( Figure 2 A,B).…”

“…Most of these patients (88–100%) exhibit a generalized nerve enlargement present at all sites with at least one region showing a CSA more than twice of the upper normal limit ( Figure 2 A,B). Nerve hypertrophy in CMT1 is already visible in children [ 27 , 33 ]. In CMT1B patients, nerves exhibit an enlarged CSA as well, but enlargement is less pronounced in comparison to CMT1A patients [ 37 , 38 , 39 ].…”

“…Growing data are available concerning rare storage diseases, for example metachromatic leucodystrophies, adrenoleucodystrophies, xantochromatosis or glucocerebrosidosis [ 27 , 145 , 146 , 147 ]. Until now, even though only limited data exist, most of the patients with storage diseases show nerve enlargement, possibly due to accumulation of intermediate metabolites within the myelin sheets, according to demyelinating NCS in most of these cases.…”

Nerve Ultrasound in Traumatic and Iatrogenic Peripheral Nerve Injury

“…CSA reference values are available for many nerves [ 18 ]. Nerve size increases during growth, so for schoolchildren it is advisable to adhere to a reference that is 50–75% of the adult size depending on age [ 19 ].…”