Anti-MuSK myasthenia gravis with prolonged remission.

Myasthenia gravis (MG) with antibodies against muscle-specific tyrosine kinase (MuSK) is a rare disorder of neuromuscular transmission affecting preferentially bulbar, neck and respiratory muscles. We report the case of a 22-year-old man who presented with diplopia on lateral gaze to both sides, facial diplegia, nasal dysarthria and dysphagia. Repetitive nerve stimulation of the trapezius and orbicularis oculi muscles showed amplitude decrements of 19% and 41% respectively supporting the diagnosis of myasthenia gravis. MUsK antibodies were positive. Corticosteroids were introduced and then tapered and discontinued at 6 months after initiation. The patient remained in remission and asymptomatic for 4 years without ongoing treatment or prior treatment with rituximab after this first relapse of MuSK-MG. MuSK- MG is considered a hard-to-treat condition and patients generally remain dependent on immunosuppression or prior treatment with rituximab. Our observation highlights that patients with MuSK-MG can have a benign course and that continued immunosuppressive or immunomodulatory therapy may not always be required.

Age Limits for Deep Brain Stimulation of Subthalamic Nuclei in Parkinson's Disease.

BACKGROUND: Clinical pre-operative predictive factors of optimal STN-DBS motor outcome in Parkinson's disease (PD) have been previously reported. However, available data involving elderly patients are conflicting. OBJECTIVE: To compare early post-operative outcomes in parkinsonian patients younger than 65 years old (group 1) vs patients 65 years old or older (group 2) at the time of surgery. METHODS: The cognitive and motor effects of DBS were evaluated by comparison of different scores obtained before (baseline) and 6 months after surgery using a repeated measures analysis of variance. RESULTS: Post-operative motor improvement (UPDRS part III and UPDRS part IV scores) and drug reduction were not statistically different between groups 1 and 2 (P > 0.05). Axial motor score which was significantly worse in group 2 in the on-drug condition before surgery was also significantly worse both in off-drug/on-stimulation and on-drug/on-stimulation conditions (P < 0.05). Similarly, cognitive performances (Wisconsin Card Sorting Test, Stroop interference test, Free and Cued Selective Reminding Test with Immediate Recall, Verbal Fluency) significantly worsened post-operatively ingroup 2. CONCLUSIONS: Although effective and safe, STN-DBS has a more negative impact on cognitive functions in elderly patient, requiring a careful preoperative selection.

Recurrent diplopia over a 30-year period: natural history of a Lewis and Sumner syndrome.

We described the case of a patient with recurrent episodes of isolated diplopia over the last 30 years. On her last event, neurological examination revealed not only a right third and sixth cranial nerves involvement, but also a right peripheral facial palsy and a motor weakness on the left ulnar territory. Electrophysiological nerves motor conduction study revealed a conduction block on the left ulnar nerve and a less severe on the right ulnar nerve. Asymmetrical upper limb sensorimotor weakness combined with conduction block and cranial nerves palsy led to a diagnosis of Lewis and Sumner syndrome (LSS). This case is unusual by the presentation of the disease and is, to our knowledge the longer natural disease course of LSS reported. Moreover, it suggests that the recurrent diplopia variant may represent a separate entity with a good prognosis even in absence of invasive treatment.