Pediatric Neurology xxx (2014) 1e4
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Idiopathic Bilateral Carpal Tunnel Syndrome in a 9-Month-Old Infant Presenting as a Pseudo-dystonia Hussein Algahtani MD FRCPC a, *, Bradley V. Watson BSc b, Jill Thomson BA b, Mohammed W. Al- Rabia MD PhD c a
College of Medicine, King Saud bin Abdualziz University for Health Sciences, Jeddah, Saudi Arabia University Hospital, University of Western Ontario, London, Ontario, Canada c College of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia b
abstract BACKGROUND: Carpal tunnel syndrome is the most common focal peripheral neuropathy seen in most electrophysiological laboratories. Although the incidence of carpal tunnel syndrome in adults is 50 to 150 cases per 100,000 people, it is rare in children. There are less than 200 case reports of carpal tunnel syndrome in children, with mucopolysaccharides and mucolipidosis being the most frequent cause. Idiopathic carpal tunnel syndrome with childhood onset occurs in less than 0.2% of cases. PATIENT: We describe a 9-month-old infant who presented with intermittent abnormal posturing movement of both hands. RESULTS: The clinical presentation and the electrophysiological studies conﬁrmed the diagnosis of carpal tunnel syndrome. His dystonic posturing had disappeared completely 3 weeks after surgical release of both ﬂexor retinaculi. CONCLUSION: We are not only reporting the youngest child with carpal tunnel syndrome, but we also report a new cause of abnormal movement disorder in children. Keywords: carpal tunnel syndrome, median neuropathy, dystonic posturing of both hands, pseudodystonia
Pediatr Neurol 2014; -: 1-4 Ó 2014 Elsevier Inc. All rights reserved.
Carpal tunnel syndrome (CTS) is the most common focal peripheral neuropathy seen in most electrophysiological laboratories. The incidence of CTS in adults is 50 to 150 cases per 100,000 people.1,2 Although CTS is common among adults, it is rare in children. Stevens et al. reported the biggest series of 1016 patients, and only two patients in their series were younger than age 14 years.2 The majority of cases in children younger than age 10 years are related to metabolic and hereditary disorders.3 Peripheral neuropathies causing abnormal movement, such as tremor and pseudo-dystonia, are well recognized entity in adults.4 We
Article History: Received November 24, 2013; Accepted in ﬁnal form January 27, 2014 * Communications should be addressed to: Dr. Hussein Algahtani; Consultant Neurologist and Head of Neurology Section; Associate Dean; College of Medicine; King Saud bin Abduaziz University for Health Sciences; P.O. Box 12723; Jeddah 21483; Kingdom of Saudi Arabia. E-mail address: [email protected]
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report a 9-month-old boy who presented with abnormal posturing of both hands without other neurological deﬁcits. The electrophysiological studies demonstrated evidence of severe bilateral CTS. The patient’s abnormal movement resolved completely after surgical release. Case report A healthy 9-month-old boy presented with a 4-month history of intermittent abnormal posturing of both hands, with left more affected than right. The arm was kept intermittently in a pronated position with hyperextension at the elbow joint. He is a product of a full-term pregnancy and spontaneous uncomplicated vaginal delivery with a normal Apgar score. His developmental, social, and mental milestones were normal for his age. There was no weakness or irritability and the rest of his neurological review was unremarkable. Family history was unremarkable for any similar condition or any metabolic disorders. General examination was normal, including head circumference. There were no signiﬁcant cutaneous lesions. His neurological, musculoskeletal, and hand examinations were normal apart from intermittent posturing of both hands and forearms. Neurological examination revealed a normal developmental quotient, cranial nerves, and motor
H. Algahtani et al. / Pediatric Neurology xxx (2014) 1e4
FIGURE 1. Neurophysiology of our patient using antidromic sensory nerve conduction studies showed absent responses from the median nerves bilaterally with normal radial and ulnar sensory responses and conduction velocities (A, B). Orthodromic, segmental median motor nerve conduction studies showed bilateral markedly delayed distal motor terminal latencies and reduced thenar motor responses (C, D). The ulnar nerve motor conduction studies were normal (E).
H. Algahtani et al. / Pediatric Neurology xxx (2014) 1e4
FIGURE 2. Anatomy of median nerve showing distal motor and sensory branches. (Color version of ﬁgure is available in the online edition.)
function, and coordination. During the examination, the patient was calm with intermittent abnormal hand movement as described. Standard electrophysiological studies were performed bilaterally on the radial, ulnar, and median nerves5 with the child being under sedation using chloral hydrate. Our results were compared with normal values established for children.6 Antidromic sensory nerve conduction studies
showed absent responses from the median nerves bilaterally with normal radial and ulnar sensory responses and conduction velocities (Fig 1A,B). Orthodromic, segmental median motor nerve conduction studies showed bilateral markedly delayed distal motor terminal latencies and reduced thenar motor responses (Fig 1C,D). The forearm conduction velocities, including the medial antebrachial cutaneous nerve, were normal (not shown). The median nerve segmental motor studies from axilla to pronator teres were normal. The ulnar nerve motor conduction studies were normal (Fig 1E). Concentric needle electromyography was normal in the left deltoid, biceps, triceps, abductor pollicis previs, ﬁrst dorsal interosseus, and abductor digiti minimi muscles were normal. Recordings from the thenar and hypothenar muscles after median nerve stimulation at wrist and elbow (not shown) demonstrated bilateral median to ulnar anastomosis in the forearm (Martin-Garuber anastomosis), which is a normal variant.7,8 These results demonstrated evidence of severe entrapment of the right and left median nerves across the region of the carpal tunnel. Computed tomography of the brain and brachial plexus and ultrasonography of the wrists were all normal. Magnetic resonance imaging of the wrists showed evidence of CTS bilaterally with bowing of the ﬂexor retinaculum. Complete blood work, including complete blood count, renal function tests, liver function tests, and glucose and thyroid function tests, were all normal. Investigations to rule out secondary causes of CTS, including mucopolysaccharidosis, and genetic testing for hereditary neuropathy with liability to pressure palsy were negative.
FIGURE 3. Causes of CTS in childhood. CTS ¼ carpal tunnel syndrome; HNPP ¼ hereditary neuropathy with liability to pressure palsies; NTOM ¼ nerve territoryoriented macrodactyly.
H. Algahtani et al. / Pediatric Neurology xxx (2014) 1e4
Clinical and electrophysiological examinations were normal in both parents and in a 2-year-old sibling. The patient had open release of both ﬂexor retinaculi approximately 2 months after his initial presentation. His dystonic posturing had disappeared completely 3 weeks postoperatively. Repeat neurophysiological testing, 6 months later, showed signiﬁcant improvement.
CTS was ﬁrst described by James Paget in 1854.9 It often manifests numbness, tingling, burning, and/or pain caused by compression of the median nerve at the wrist. The carpel tunnel is a cylindrical inelastic cavity connecting the volar forearm with palm. It is located at the base of the palm, just distal to the wrist crease. It is bounded by the transverse carpal ligament (ﬂexor retinaculum) ventrally, the transverse arch of the carpel bones dorsally; the hook of the hamate, tubercle, and pisiform medially; and the scaphoid; trapezium; and ﬁbroosseous “ﬂexor carpi radialis sheath” sheath laterally (Fig 2). Nine ﬂexor tendons traverse the carpel tunnel along with the median nerve. Sensory branches from the median nerve supply the three radial digits and the radial half of the fourth digit. The palmar sensory cutaneous branch of the median nerve supplies the palmar surface, and arises, on average, 6 cm proximal to the transverse carpal ligament. Therefore, the palm is generally not affected in CTS.10 The pathophysiology of CTS is not fully understood; however, a combination of mechanical trauma, increased pressure in the carpal tunnel, and ischemic injury to the medial nerves have been implicated. Although CTS is the most common reason for referral to most adult electromyelography laboratories, but it is rare in children. Median neuropathies account for less than 1% of all pediatric neuropathies referred to the neurophysiology laboratory.11 It was ﬁrst reported in childhood in 1958 by Martin and Masse. They reported three patients with CTS who presented with severe pain with no cause identiﬁed.12 Two were helped by surgical release, while the other patient improved following oral steroids. In adults, entrapment of the median nerve is more common than that of the ulnar and radial nerves. In children, mononeuropathies in the arm have a relatively equal distribution when comparing median, ulnar, and radial neuropathies. In contrast to adults, whose median nerve lesion at the wrist is identiﬁed 100 times more frequently than at proximal levels, pediatric median mononeuropathies are more frequently occurring in proximal than distal sites.11
Although electrophysiological ﬁndings of pediatric CTS are similar to those in adults, the clinical features are somewhat different. Initially, the symptoms are vague and nonspeciﬁc, including clumsiness or weakness and wrist or hand pain. Children are often too young to communicate their problem. Childhood CTS are usually caused by speciﬁc causes such as mucopolysaccharidosis or other storage disorders. In these cases, the symptoms of CTS can be masked by skeletal dysplasias and joint stiffness. Figure 3 shows causes of CTS in children. CTS presenting as an abnormal movement disorder (pseudo-dystonic hands) is a rare occurrence. The youngest child with CTS reported in the literature was a 2-year-old child with disseminated angiomatosis.13 The youngest child with idiopathic CTS reported in the literature was 4 years old.14 Here we are not only reporting the youngest child with CTS, but we also report a new cause of abnormal movement disorder in children. References 1. Phalen GS. The carpal tunnel syndrome. Seventeen years experience in diagnosis and treatment of six hundred ﬁfty four hands. J Bone Joint Surg Am. 1966;48A:211-228. 2. Stevens JC, Sun S, Beard CM, O’Fallon WM, Kurland LT. Carpal tunnel syndrome in Rochester, Minnesota, 1961-1980. Neurology. 1988;38: 134-138. 3. Davis L, Vedanarayanan VV. Carpal tunnel syndrome in children. Pediatric Neurology. 2014;50:57-59. 4. Smith IS, Furness P, Thomas PK. Tremor in peripheral neuropathy. In: Findley LJ, Capildeo R, eds. Movement Disorders: Tremor. London: Macmillan; 1984:399-406. 5. American Association of Electrodiagnostic Medicine. Practice parameter for electrodiagnostic studies in carpal tunnel syndrome: summary statement. Muscle Nerve. 1999;22(Suppl 8):S141-S143. 6. Miller RG, Kuntz NL. Nerve conduction studies in infants and children. J Child Neurol. 1986;1:19-26. 7. Sun SF, Streib EW. Martin-Garuber anastomosis: electromyographic studies, part II. Electromyogr Clin Neurophysiol. 1983;23:271-285. 8. Streib EW. Ulnar-to-median nerve anastomosis in the forearm: electromyographic studies. Neurology. 1979;29:1534-1537. 9. Paget J. Lectures on Surgical Pathology. Philadelphia, PA: Lindsay and Blakiston; 1854. 10. Dorwart BB. Carpal tunnel syndrome: a review. Semin Arthritis Rheum. 1984;14:134-140. 11. Deymeer F, Jones Jr HR. Pediatric median mononeuropathies: a clinical and electromyographic study. Muscle Nerve. 1994;17:755-762. 12. Martin C, Masse P Carpal tunnel syndrome in children. Arch Fr Pediatr. 1958;15:930-940 [in French]. 13. Poilvache P, Carlier A, Rombouts JJ, Partoune E, Lejeune G. Carpal tunnel syndrome in childhood: report of ﬁve new cases. J Pediatr Orthop. 1989;9:687-690. 14. Van Meir N, De Smet L. Carpal tunnel syndrome in children. J Pediatr Orthop B. 2005;14:42-45.