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					       단신보고                                                         J Korean Neurol Assoc / Volume 24 / February, 2006




            화학치료에 현저한 반응을 보인 소세포폐암을 동반한
            Lambert-Eaton Myasthenic Syndrome
            원광대학교 의과대학 신경과학교실, 원광의과학 연구소


            신대수 박현영 조광호




            Dae-Soo Shin, M.D., Hyun-Young Park, M.D., Kwang-Ho Cho. M.D.

            Department of Neurology, Wonkwang University School of Medicine, Wonkwang Medical Science Research Center.




  The Lambert-Eaton myasthenic syndrome (LEMS) is an          seemed to be worse in the early mornings and then
uncommon presynaptic neuromuscular junction disorder.         improved later in the daytime. He also complained of dry
It is associated with cancer in 50 to 60% of cases, of        mouth and intermittent aspiration of water. He had been
which the overwhelming majority are small cell lung           smoking one pack of cigarettes a day for 40 years. The
                 1
carcinomas (SCLC) . We describe here a rare case of LEMS      family history was unremarkable. Neurological exami-
with typical small cell lung cancer, which has shown          nation showed mild proximal muscle weakness (MRC
clinical and electrophysiological remission after chemo-      grade 4) and hypoactive tendon reflexes. Cranial nerve
       3
therapy .                                                     and sensory examinations were normal. A nerve conduction
                                                              study revealed low amplitude compound muscle action
                       CASE                                   potentials (CMAPs) in the left median and bilateral ulnar
                                                              nerves with normal conduction velocities. In suspicion of
  A 65-year-old man presented with progressive                LEMS, a repetitive nerve stimulation test (RNST) was
weakness of the leg in July 2004. Four months ago, he         performed on the left abductor digiti quinti (ADQ), flexor
felt stiffness in both legs. He had noticed increasing        carpi ulnaris (FCU), trapezius, obicularis oculi and
                                                                                                2
difficulty in climbing stairs two months before, which        nasalis muscles using Oh’s methods . We have examined
                                                              facilitation after 30 seconds of maximum volunatary
                                                              contraction and incremental response at high rate (50 Hz)
                                                              of stimulation for 1 sec in ADQ. The results fully satisfied
                                                              commonly used diagnostic criteria for LEMS (Fig. 1).
                                                              Tensilon (Edrophonium) test and anti-acetylcholine
                                                              receptor antibody assay were negative. Chest X-ray
                                                              revealed a well defined mass on the left upper parahilar



                                                                     J Korean Neurol Assoc Volume 24 No. 1, 2006
신대수 박현영 조광호



                                                                       2004.9.23 (Secone test)




Figure 1. Postexercise fascilitation and incremental response at high rate of stimulation in the abductor digiti minimi muscle. Note
definite facilitation at high rate of stimulation is achieved by prolonged stimulation for 2 seconds in second test. (A) Compound
muscle action potential (CMAP) before exercise. (B) CMAP after 30 seconds of exercise. (C) Response at 50 Hz stimulation for 1
second.

                                                                                                        3,4
                  2004.6.23 (First test)
lung. Central pulmonary malignancies with invasion of                LEMS, they are usually SCLC.             The initial treatment
left pulmonary artery and para-aortic space were                     should be aimed at any tumor presence, since the weakness
evaluated by chest computed tomography (CT). Broncho-                frequently improves with effective cancer therapy; no
scopic biopsy identified small-cell lung cancer. Four                further LEMS treatment may be necessary in some
                                                                              5
courses of chemotherapy (carboplatin+etoposide) were                 patients.
performed and resulted in a marked response in the                     In our case, clinical and electrophysiological remission
SCLC. After the third course of chemotherapy, marked                 was achieved by chemotherapy. It is noteworthy that our
improvement of the muscle weakness was recognized.                   case was initially satisfied by the electrophysiological
Three months later, neurological examination showed no               criteria of LEMS, and the follow-up study three months
proximal weakness (MRC grade 5) and normoactive                      following chemotherapy revealed a marked improvement
tendon reflexes. The second RNST and chest X-ray were                compared to previous study. It is known that the
performed three months later, which showed marked                    weakness frequently improves with effective cancer
                                                                                        6,7
improvement compared to the previous study (Fig. 1).                 therapy in LEMS.
                                                                       Our case demonstrates serial RNST is helpful for
                     DISCUSSION                                      verifying the correlation between electrophysiological
                                                                     remission and clinical improvements.
  We describe a case of LEMS who showed marked
improvement after treatment for small cell lung carcinoma.                               REFERENCES
LEMS results from an autoimmune attack directed
against the voltage-gated calcium channels (VGCCs) on
the presynaptic motor nerve terminal. It was first
described as a paraneoplastic syndrome in patients with
lung cancer, but we now know about half of the patients
with LEMS do not have cancer. When tumors occur in


     J Korean Neurol Assoc Volume 24 No. 1, 2006
화학치료에 현저한 반응을 보인 소세포폐암을 동반한 Lambert-Eaton Myasthenic Syndrome




                          J Korean Neurol Assoc Volume 24 No. 1, 2006

				
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