Byung Ok Choi

Hereditary neuropathy with liability to pressure palsies (HNPP) patients of Korean ancestry with chromosome 17p11.2-p12 deletion

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant inherited disorder characterized by recurrent pressure palsies. Most HNPP patients have a 1.5 mb deletion in chromosome 17p11.2-p12. The present study aimed at evaluating the deletion of the 17p11.2-p12 region in Korean subjects with families exhibiting HNPP phenotype, and to determine the clinical, electrophysiological and morphological aspects specifically associated with this deletion in HNPP patients. By genotyping six microsatellite markers (D17S921, D17S955, D17S1358, D17S839, D17S122 and D17S261), HNPP with the deletion was observed in 79% (19 of 24) of HNPP families. Nerve conduction studies were performed in 35 HNPP patients from these 19 families. The observed HNPP deletion frequency in Koreans is consistent with findings in other populations. Disease onset occurred at a significantly earlier age in patients with recurrent pressure palsies than in those with a single attack (P<0.01). Nerve conduction studies demonstrated diffuse mild to moderate slowing of nerve conduction velocities that were worse over the common entrapment sites, regardless of the clinical manifestations. A long duration of compound muscle action potentials without a conduction block or a temporal dispersion is a characteristic of this disease. A sural nerve biopsy with teasing was performed in four patients, and tomacula of the myelin sheath was found in 56.4%. Our findings appear to support the existence of a phenotype/genotype correlation in HNPP patients of Korean ancestry with the deletion, and suggest that HNPP patients with earlier symptom onset face an increased chance of having recurrent attacks.

Brachial plexopathy caused by subclavian artery aneurysm in Behçet's disease

As the cause of brachial plexopathy, an aneurysm of the subclavian artery is rare and mostly related to trauma. Early diagnosis and treatment is very important because the arterial aneurysm itself is life‐threatening and nerve injury can be reversible in cases of early treatment. We report a patient with Behçets disease having a right brachial plexopathy caused by a nontraumatic aneurysm of the right subclavian artery.

PO5.34 Different Clinical and Electrophysiological Characteristics between CMT1A and CMTX Patients

hands according to neurophysiological criteria. Mean nerve conduction velocities from digit to C1, C2, C3 and C4 were 53.0±10.2 ms, 47.9±7.3, 38.2±8.6 ms, and 38.0±8.8 ms respectively. Mean segmental nerve conduction velocities of C1 C2, C2 C3 and C3 C4 are 41.8±16.9 m/s, 23.4±13.3 and 36.5±11.0 m/s respectively with a minimum value from C2 C3; which represents the segment of median nerve across the carpal ligament. When compared with C2-C3 segment there is a significant difference of nerve conduction velocities of C1 C2 (p < 0.001) and C3 C4 (p = 0.001). Median sensory nerve action potentials (MSNAP) at C1, C2, C3 and C4 were 1.3±8.5, 6.6±3.8, 8.1±5.1mV and 9.7±5.5mV respectively. Median motor distal latency is negatively correlated (r = .552) to NCV of C2 C3 segment (p < 0.01). Conclusions: The maximum slowing of median sensory nerve conduction velocity was obtained across the distal segment of carpal ligament.

PO5.26 Characteristics of the Proximal Lower Limb MRI in Korean Charcot-Marie-Tooth Patients with Demyelinating Neuropathy and Axonal Neuropathy

diagnostic criteria for demyelinated nerves were fulfilled in 5 (38%). Albuminocytologic dissociation of CSF in 6. No autoantibody was detected in all tested patients. Conclusions: Sensory symptoms of Ab and Ad fibers transmitting vibratory sense and sharp pain with symmetric centrifugal patterns of trunk and limbs, decreased SNAPs, absent H-reflex suggest pathology as demyelinating sensory polyneuropathy, not ganglionopathy. However, albuminocytologic dissociation, multiple combination of demyelinating NCS and minor weakness in most patients suggest sensory fiber myelinspecific disease, triggered by virus or bacteria, as superantigen, or by activation of primed CD4 T helperor memory-cell by molecular mimicrying antigen.

PO7.9 Phenotypes of 117 Korean Patients with Mitochondrial Disorders

Background: Ventilatory failure is a common and potentially lifethreatening complication of myotonic dystrophy. It usually parallels the muscular manifestations, but there are some cases that ventilatory failure is a presenting symptom without limb weakness. In that case, muscular dysfunction alone is insufficient to account for the ventilatory failure. Case report: A 34-year-old man with history of diabetes and hypercholesterolemia presented to the hospital with a 2-month history of gradually progressive hypersomnia and supine dyspnea. In the emergency room, he was cyanotic and confused, so he was intubated and admitted to intensive care unit. He was obese (BMI: 32.7) and had facial features characteristic of myotonic dystrophy including frontal boldness, hatched face, without ptosis, facial drooping and limb atrophy. Neurologic examination demonstrated mild generalized weakness (MRC grade IV+) and percussion myotonia. Deep tendon reflex were hypoactive, and sensation was normal. Arterial blood gas analysis demonstrated severe hypoxia and hypercapnia with a respiratory acidosis. No cardiac, pulmonary and pharmacologic causes were identified. Pulmonary function tests revealed a severe restrictive ventilatory insufficiency. Electromyography showed myotonic discharges and genetic analysis showed classic phenotype of myotonic dystrophy type 1. Polysomnographic study revealed sleep apnea of central origin. He responded to ventrilatory support with BIPAP. Conclusions: We report a case of myotonic dystrophay presenting with ventilatory failure without significant limb weakness or any provocative challenge such as anesthesia or surgery. The PFT and polysomnographic findings support that this patient’s respiratory dysfunction was due to dual origin central and peripheral.

PO5.44 Evaluation of Quality of Life in Korean Charcot-Marie-Tooth Patients

Background: To investigate the correlation between the slowing of median nerve conduction velocity at the segment of forearm (fMCV) and the severity of the entrapment neuropathy in CTS, and to explore the possible pathogenesis of the slowed fMCV. Methods: Consecutive 66 CTS patients (126 hands) that satisfied the diagnostic criteria were enrolled and the ageand gender-matched 96 volunteers (96 non-dominant hands) were served as controls. Routine nerve conduction studies were performed. The distal motor latency (DML) of median nerve and thenar compound muscle action potentials amplitude (CMAP) were taken as indications of CTS severity, and the correlation between the severity and fMCV was analyzed. Results: As to ulnar nerve, there is no difference of motor and sensory conduction between patients group and controls. In the patient group, the median distal motor latency DML (ms) was 5.0±1.3, significantly longer (P= 0.000); the CMAP amplitude (mV) of abductor pollicis brevis was 7.3±2.9, decreased significantly (P= 0.000); the wpMCV (m/s) was 22.2±7.3, slowed significantly (P= 0.000); the fMCV (m/s) was 53.7±5.5, slowed significantly (P= 0.000), compared with the controls; and there was a significantly negative correlation between the fMCV and DML (r = 0.35, P< 0.01, n = 126) and positive correlation between fMCV and CMAP amplitude (r = 0.18, P< 0.05, n = 96). Conclusions: The conduction abnormalities of median nerve at the segment of forearm may be associated with the lesion severity in the patient with CTS, in which the pathogenesis may be retrograde axonal degeneration.

PO5.14 Seven Early-Onset Axonal Neuropathy Patients with Brain Involvements

Background: Nerve injury (NI) related to unsafe intramuscular injection (INI), a preventable iatrogenic hazard, is not uncommon in developing countries. Very few studies have characterized the syndrome of IMIrelated radial nerve injury. Methods: This is a retrospective review of the case records of all patients with wrist drop, as the presenting feature, referred for electrodiagnostic studies between January 2006 and December 2008. Difference in the amplitude between distal and proximal CMAP greater than 20% was considered as conduction block. Needle EMG of the muscles innervated by radial nerve was also done. Injury was classified as neuropraxia, axonotmesis, and neurotmesis. Results: Fifty-five patients were evaluated during the study period (mean age, 42.16+15.05 yrs, range, 17 71 yrs; M:F, 4.5:1). The etiological spectrum included: pressure palsy (PP) 34 (62%), IMI-related NI (IMINI) 12 (22%), diabetic sensory neuropathy with pressure palsy (DSN-PP) 6 (11%), mononeuritis multiplex (MNM), HNPP and posterior interosseous nerve palsy (PINP) 1 each, 3 (5%). Electrodiagnostic studies were suggestive of neuropraxia in 36 (PP 28, DSN-PP 6, MNM 1, HNPP 1), axonotmesis 11 (chronic PP 6, PINP 1, IMINI 4) and neurotmesis in 8 (all IMINI). Site of lesion on electrodiagnostic studies: at the spiral grove 44 (80%), above the sensory branch 10 (18%), and forearm 1 (2%). Outcome: IMINI (12): no recovery in 8 (all neurotmesis) and partial recovery in 4 (all axonotmesis); PP (34): complete recovery in 28 (all neuropraxia) and partial recovery in 6 (all axonotomesis). Of the remaining 7, 6 had complete recovery and the patient with PINP had partial improvement. Conclusions: In this part of the world the etiological spectrum of wrist drop varied, and IMI-related radial nerve injury accounted for about onefifth, and it was associated with a poor prognosis.

PO5.16 Schwannoma and Demyelinating Peripheral Neuropathy

Background: Nerve injury (NI) related to unsafe intramuscular injection (INI), a preventable iatrogenic hazard, is not uncommon in developing countries. Very few studies have characterized the syndrome of IMIrelated radial nerve injury. Methods: This is a retrospective review of the case records of all patients with wrist drop, as the presenting feature, referred for electrodiagnostic studies between January 2006 and December 2008. Difference in the amplitude between distal and proximal CMAP greater than 20% was considered as conduction block. Needle EMG of the muscles innervated by radial nerve was also done. Injury was classified as neuropraxia, axonotmesis, and neurotmesis. Results: Fifty-five patients were evaluated during the study period (mean age, 42.16+15.05 yrs, range, 17 71 yrs; M:F, 4.5:1). The etiological spectrum included: pressure palsy (PP) 34 (62%), IMI-related NI (IMINI) 12 (22%), diabetic sensory neuropathy with pressure palsy (DSN-PP) 6 (11%), mononeuritis multiplex (MNM), HNPP and posterior interosseous nerve palsy (PINP) 1 each, 3 (5%). Electrodiagnostic studies were suggestive of neuropraxia in 36 (PP 28, DSN-PP 6, MNM 1, HNPP 1), axonotmesis 11 (chronic PP 6, PINP 1, IMINI 4) and neurotmesis in 8 (all IMINI). Site of lesion on electrodiagnostic studies: at the spiral grove 44 (80%), above the sensory branch 10 (18%), and forearm 1 (2%). Outcome: IMINI (12): no recovery in 8 (all neurotmesis) and partial recovery in 4 (all axonotmesis); PP (34): complete recovery in 28 (all neuropraxia) and partial recovery in 6 (all axonotomesis). Of the remaining 7, 6 had complete recovery and the patient with PINP had partial improvement. Conclusions: In this part of the world the etiological spectrum of wrist drop varied, and IMI-related radial nerve injury accounted for about onefifth, and it was associated with a poor prognosis.