Abstract

Carpal tunnel syndrome (CTS) is rarely seen in children. A literature search in 1989 revealed 52 published cases. The authors review 163 additional cases that were published since that date. The majority of these cases were related with a genetic condition. The most common aetiology was lysosomal storage disease : mucopolysaccharidoses (MPS) in 95 and mucolipidoses (ML) in 22. In CTS secondary to MPS, clinical signs typical of adult CTS are rarely seen, and difficulty with fine motor tasks is the most frequent finding. CTS in MPS does not seem to be prevented by bone marrow transplantation, the usual treatment for the condition. CTS is probably due to a combination of excessive lysosomal storage in the connective tissue of the flexor retinaculum and a distorted anatomy because of underlying bone dysplasia. Mucolipidoses come next in the aetiology, with essentially similar symptoms. The authors found in the literature 11 cases of primary familial CTS, a condition which presents as an inheritable disorder of connective tissue mediated by an autosomal dominant gene ; the symptoms may be more typical in some cases, but are more similar to MPS in others. A case with self-mutilation has been reported. Hereditary neuropathy with liability to pressure palsies (HNPP) is a rare autosomal dominant condition characterised by episodes of decreased sensation or palsies after slight traction or pressure on peripheral nerves ; it may also give symptoms of CTS. Schwartz-Jampel syndrome (SJS), another genetic disorder with autosomal recessive skeletal dysplasia, is characterised by varying degrees of myotonia and chondrodysplasia ; it has also been noted associated with CTS in a child. Melorrheostosis and Leri's syndrome have also been noted in children with CTS, as well as Déjerine-Sottas syndrome and Weill-Marchesani syndrome. Among non-genetic causes of CTS in children, idiopathic cases with children onset have been reported, usually but not always related with thickening of the transverse carpal ligament. Intensive sports practice has been reported as an aetiological factor in several cases of childhood CTS. Nerve territory oriented macrodactily, a benign localised form of gigantism, is another unusual cause of CTS in children, as are fibrolipomas of the median nerve or intraneural perineuroma or haemangioma of the median nerve. Acute cases have been reported in children with haemophilia, secondary to local bleeding. Another local cause is a musculotendinous malformation of the palmaris longus, the flexor digitorum superficialis, the flexor carpi radialis brevis (a supernumerary muscle), the first lumbricalis or the palmaris brevis. Isolated cases of childhood CTS have also been reported in Klippel-Trenaunay syndrome, in Poland's syndrome and in scleroderma. Finally, several cases have been noted following trauma, most often related with epiphysiolysis of the distal radius. Immediate reduction has cleared the problem in most cases, but exploration of the median nerve should be considered otherwise, and also in cases with delayed occurrence of symptoms. Overall 145 of the 163 reviewed cases have undergone open carpal tunnel release. Childhood CTS often has an unusual presentation, with modest complaints and children are often too young to communicate their problem. In CTS with specific aetiologies such as storage disease, the symptoms may be masked by the skeletal dysplasia and joint stiffness. Every child with even mild symptoms must be thoroughly examined and a family history must be taken. Children with storage disease may benefit from early clinical and electrophysiological screening before they develop obvious clinical signs.