Abstract

Background
Carpal tunnel syndrome (CTS) is rare in children but is a recognised complication of the mucopolysaccharidoses (MPS). Clinicians should have a low threshold of suspicion for CTS in this group as symptoms may be atypical or minimal. If untreated, CTS can cause significant loss of hand function. We present findings in 11 children with mucopolysaccharidoses and suspected CTS, and propose guidelines for screening for CTS in children with these disorders.

Methods
Clinical and electrodiagnostic data of 11 children with mucopolysaccharidoses, who were suspected on clinical grounds to have CTS, 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 MPS I, five had MPS II, one had MPS III and two had 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 five years age. Six underwent median nerve decompression. Four of these had recurrent symptoms several years after surgery, which 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 their symptoms of CTS, and of the treatment received for mucopolysaccharidosis.