Lewis summer syndrome GUIDE

Summary
The Lewis- Sumner syndrome (LSS) is a dysimmune multifocal demyelinating sensorimotor neuropathy. It should be considered as a clinical asymmetrical variant of chronic immune demyelinating polyneuropathy (CIDP). LSS is five times less frequent than CIDP whose prevalence is between 2 and 7/ 100,000. Patients with LSS usually present with an asymmetrical involvement of the upper limb with distal sensorimotor deficit in median or ulnar territories. A purely sensory onset with numbness and paresthesia or pain in median or ulnar territory is observed 30% of cases. A lower limb onset is present in 30% of patients with a distal and asymmetrical sensorimotor deficit. Amyotrophy and cranial nerve involvement may be observed in 50% and 20% of patients, respectively. LSS could mimick a nerve entrapment or a vasculitis. The course is progressive or remitting. Electrophysiological pattern associates a multifocal motor demyelination with conduction blocks mostly situated in the forearm. Contrarily to CIDP, other conduction anomalies (reduction of truncal motor nerve velocities, prolonged distal latencies or prolonged F waves) occur rarely outside the blocked nerve territory. Sensory conduction shows a multifocal sensory involvement. Sural nerve biopsy in LSS show elements consistent with a primary demyelination, indistinguishable from that seen in typical CIDP. However nervous biopsy is not necessary to establish the diagnosis. Serum anti-GM1 antibodies are negative and CSF protein content is usually normal or mildly elevated with a mean value of 0.7 g/l. LSS is characterized by a responsiveness to IVIg and steroids. For LSS patients, a treatment similar to that of CIDP, with a first line treatment with intravenous Ig (IVIg) (2g/kg/course), is recommended. Patients who do not respond after 2 or 3 courses should be switched to prednisone; a dose of 1mg/kg/day should be maintained for 4-6 weeks, then slowly tapered. Plasma exchanges are not recommended in LSS. *Author: Dr K. Viala (August 2003)*.

Update : 07/08/2005

Rinsho Shinkeigaku. 2000 Nov;40(11):1126-9.

[Lewis-Sumner syndrome presenting unilateral quadriceps amyotrophy as an initial symptom]

Second Department of Internal Medicine, Fukui Medical University.

We report a 55-year-old man with a chief complaint of wasting and weakness of the left quadriceps muscle. At age 54, he noticed difficulty in running and weakness in the left thigh, which gradually progressed. On the first admission to our hospital, based on the nerve conduction studies (NCS), the muscle biopsy findings showing neurologenic changes, and no abnormality of spinal MRI, we diagnosed as unilateral quadriceps amyotrophy, which resulted from an atypical form of spinal progressive muscular atrophy. One year later, he showed the bilateral hand weakness, conduction blocks on the right median and ulnar nerves by NCS, and the presence of serum anti-GM 1 antibody. From these findings, Lewis-Sumner syndrome was diagnosed. The therapy of high-dose intravenous immunoglobulin moderately improved his symptoms. The clinical symptoms of quadriceps amyotrophy is produced by various disorders including spinal progressive muscular atrophy, spinal extradural arachnoid cyst, rimmed vacuole myopathy, Becker dystrophy, limb-girdle dystrophy, and focal myositis. However, there have been no reports of a case of Lewis-Sumner syndrome. It is important to consider Lewis-Sumner syndrome in the differential diagnosis of quadriceps amyotrophy.

Publication Types:

Case Reports

PMID: 11332195 [PubMed - indexed for MEDLINE]

Rinsho Shinkeigaku. 1999 Jan;39(1):107-9.

[Diagnosis and treatment of multifocal motor neuropathy (Lewis-Sumner)]

Kaji R.

Department of Neurology, Kyoto University Hospital.

We made a retrospective long-term follow-up study of 25 patients with multifocal motor neuropathy (Lewis-Sumner). The diagnosis was based upon criteria modified from those of AAEM (Sumner 1997). The electrophysiological findings indicating conduction block or focal demyelinative lesions were more diagnostic than anti-GM 1 antibody titers, which were elevated in only 40% of these patients. Demonstration of definite conduction block was not always possible in those patients who responded favorably to intravenous immunoglobulins (IVIg), whereas indirect pieces of evidence such as F-wave abnormalities or focal conduction delay or dispersion were equally helpful. IVIg had superior outcome to cyclophosphamide, which sometimes caused serious adverse effects. Three patients with severe axonal involvement showed elevated monospecific antibodies to GalNAc-GD1a.

: Follow-up study and response to treatment in 23 patients with Lewis-Sumner syndrome.
Federation de Neurophysiologie Clinique, Hopital de la Salpetriere, 47 Boulevard de l'Hopital, 75651 Paris cedex 13, France. karine.viala@psl.ap-hop-paris.fr

Lewis-Sumner syndrome (LSS) is a dysimmune peripheral nerve disorder, characterized by a predominantly distal, asymmetric weakness mostly affecting the upper limbs with sensory impairment, and by the presence of multifocal persistent conduction blocks. The nosological position of this neuropathy in relation to multifocal motor neuropathy (MMN) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is still debated. We report the clinical, biological and electrophysiological features, the course and the response to treatment in 23 LSS patients. The initial symptoms started in the distal part of an upper limb in 70% of patients. They were sensorimotor in 65% and purely sensory in 35% of patients. A cranial nerve involvement was observed in 26% of patients and a distal limb amyotrophy in 52%. The CSF protein level was normal in 67% of patients and mildly elevated in the remainder. None had serum anti-GM1 antibodies. There were multiple motor conduction blocks (average of 2.87/patient), predominantly located in the forearm, whereas demyelinating features outside the blocked nerves were rare. Abnormal distal sensory potentials were found in 87% of patients. The electrophysiological pattern suggests a very focal motor fibre demyelination sparing the nerve endings, whereas sensory fibre involvement was widespread. The course was chronic progressive in 71% of patients and relapsing-remitting in the others. During the follow-up study (median duration of 4 years), half of the patients progressed with a multifocal pattern and the distribution of the motor deficit remained similar to the initial presentation. The other patients showed a progression to the other limbs, suggesting a more diffuse process. Fifty-four percent of the patients treated with intravenous immunoglobulin showed an improvement, compared with 33% of the patients treated with oral steroids. Overall, 73% of patients had a positive response to immune-mediated therapy. LSS may be distinguished from MMN by the presence of sensory involvement, the absence of serum anti-GM1 antibodies and, in some cases, a positive response to steroids. In some of the patients in our study, LSS evolved into a more diffuse neuropathy sharing similarities with CIDP. Others had a clinical course characterized by a striking multifocal neuropathy, which suggests underlying mechanisms different from CIDP. Overall, whatever the clinical course, LSS responded to immune-mediated treatment in a manner similar to CIDP.

PMID: 15289267 [PubMed - indexed for MEDLINE]