11. Carpal tunnel syndrome in pediatric mucopolysaccharidoses

Abstract

Background Carpal tunnel syndrome is rare in children but is a recognised complication of the mucopolysaccharidoses. Clinicians should have a low threshold of suspicion for carpal tunnel syndrome in this group as symptoms may be atypical or minimal, especially in those with intellectual disabilities secondary to mucopolysaccharidoses. If untreated, carpal tunnel syndrome can cause significant, potentially permanent loss of hand function. We present findings in 11 children with mucopolysaccharidoses and suspected median neuropathies at the wrist, and propose guidelines for screening for carpal tunnel syndrome in children with these disorders. Methods Clinical and electrodiagnostic data of 11 children with confirmed mucopolysaccharidoses by enzymatic ± molecular testing, who were suspected on clinical grounds to have carpal tunnel syndrome, was reviewed. All subjects underwent motor and sensory conduction studies of bilateral median and ulnar nerves. The presence of carpal tunnel syndrome and its severity was determined. Subsequent details of intervention (s) and recurrence were noted. Results Three children had Hurler syndrome (MPS I), five had Hunter syndrome (MPS II), one had Sanfilippo syndrome (MPS III) and two had Morquio syndrome (MPS IV). Seven had motor and three sensory features referable to median nerve compression. Nine of the eleven children (2/3 with MPS I, 5/5 with MPS II, 0/1 with MPS III, 2/2 with MPS IV) had median neuropathies at the wrist (eight bilateral, one unilateral), which were mild in three, moderate in five, and severe in one. Three children presented with symptoms at 5 years age. Six underwent median nerve decompression. Four of these had recurrent symptoms several years after surgery. Recurrent carpal tunnel syndrome was confirmed on nerve conduction studies in two cases. To the best of our knowledge, this is the first report of carpal tunnel syndrome in MPS IV. Conclusion Some children with mucopolysaccharidoses experience early development of at least moderately severe carpal tunnel syndrome. We recommend screening for median neuropathies at the wrist from age 5 years for children with mucopolysaccharidoses, particularly types I, II and IV, regardless of whether they are symptomatic or asymptomatic of carpal tunnel syndrome and of the treatment received for their mucopolysaccharidosis.