Electromyography in diagnostic of median nerve lesion in carpal tunnel syndrome of children with mucopolysaccharidoses

Carpal tunnel syndrome (CTS) is a frequent syndrome in adults, but is very rare in children. CTS was described in children with mucopolysaccharidoses (MPS) as condition due to the deformation of carpal bones, deposition of glycosaminoglycans in tendosynovial tissue and connective tissue of flexor retinaculum. Electromyography is essential method for diagnostic CTS in children because typical symptoms of CTS (paresthesia, numbness of hand and fingers, atrophy and paresis of certain muscles) seen in adults are absent or not realized by children with MPS because of cognitive deficit despite the presence of nerve involvement. EMG results from 40 children with different types of MPS (age 1 year 8 months to 18 years) are presented. Neurophysiologic abnormalities related to CTS were found in every child with MPS I, in 80,9 % of cases – with MPS II and in every case – with MPS VI; no EMG signs of median nerve lesions in
carpal channel were detected in patients with MPS III and MPS IV. CTS was bilateral in children with MPS I, II and VI, but usually
there was an asymmetry of changes. We revealed CTS in one patient with MPS II as early as at the age 2 years 11 months. All children with MPS II had already CTS at the age of 4 years except one patient. Children with MPS I and MPS VI were not investigate before the age 4 years old, but one child 4 years old with MPS I had severe CTS. In children with MPS atrophy of thenar eminence muscles developed rapidly as complication of CTS. Therefore we recommend repeating of EMG regularly to identify earliest signs of median nerve disturbance in carpal channel and opportune surgical decompression of the entrapped nerve. It allows preserving normal function of hand that it is very important for adequate child development and quality of life.

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