Motor and sensory conduction failure in overlap of Guillain-Barré and Miller Fisher syndrome: two simultaneous cases.

We report 2 patients diagnosed simultaneously with an overlap of Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS), who had anti-GT1a, anti-GQ1b, anti-GD1a and anti-GD1b antibodies. There was no identifiable specific preceding infection. Both patients presented with upper and lower limb paresthesias and severe weakness, bulbar and facial weakness, ophthalmoparesis and areflexia. In one, electrophysiology demonstrated multifocal conduction blocks (CBs) and mild motor conduction velocity slowing in intermediate segments and absent sensory nerve action potentials (SNAPs). The patient improved rapidly and fully recovered within 18 days from onset. CBs resolved, distal compound muscle action potential (CMAP) amplitudes increased and SNAPs normalized on subsequent testing. In the other patient, initial studies showed low/normal CMAPs, with absent SNAPs, without demyelinating features. This patient fully recovered within 21 days from onset. CMAPs markedly increased, SNAPs improved marginally. These 2 patients exhibited features indicative of the pathophysiological mechanism of conduction failure in motor and sensory fibers. This phenomenon relates to rapidly resolving CBs possibly induced by the transitory and limited attack of antiganglioside antibodies at the axolemma of the nodes of Ranvier not progressing to axonal degeneration. These cases widen the range of GBS subtypes in which reversible conduction failure has been described, to include overlap syndromes with MFS. The factors determining the electrophysiology, as well as the rate, degree and quality of recovery in GBS subtypes remain uncertain at the present time.

Lamotrigine for neuroprotection in secondary progressive multiple sclerosis: a randomised, double-blind, placebo-controlled, parallel-group trial.

BACKGROUND: Partial blockade of voltage-gated sodium channels is neuroprotective in experimental models of inflammatory demyelinating disease. In this phase 2 trial, we aimed to assess whether the sodium-channel blocker lamotrigine is also neuroprotective in patients with secondary progressive multiple sclerosis. METHODS: Patients with secondary progressive multiple sclerosis who attended the National Hospital for Neurology and Neurosurgery or the Royal Free Hospital, London, UK, were eligible for inclusion in this double-blind, parallel-group trial. Patients were randomly assigned via a website by minimisation to receive lamotrigine (target dose 400 mg/day) or placebo for 2 years. Treating physicians, evaluating physicians, and patients were masked to treatment allocation. The primary outcome was the rate of change of partial (central) cerebral volume over 24 months. All patients who were randomly assigned were included in the primary analysis. This trial is registered with ClinicalTrials.gov, NCT00257855. FINDINGS: 120 patients were randomly assigned to treatment (87 women and 33 men): 61 to lamotrigine and 59 to placebo. 108 patients were analysed for the primary endpoint: 52 in the lamotrigine group and 56 in the placebo group. The mean change in partial (central) cerebral volume per year was -3.18 mL (SD -1.25) in the lamotrigine group and -2.48 mL (-0.97) in the placebo group (difference -0.71 mL, 95% CI -2.56 to 1.15; p=0.40). However, in an exploratory modelling analysis, lamotrigine treatment seemed to be associated with greater partial (central) cerebral volume loss than was placebo in the first year (p=0.04), and volume increased partially after treatment stopped (p=0.04). Lamotrigine treatment reduced the deterioration of the timed 25-foot walk (p=0.02) but did not affect other secondary clinical outcome measures. Rash and dose-related deterioration of gait and balance were experienced more by patients in the lamotrigine group than the placebo group. INTERPRETATION: The effect of lamotrigine on cerebral volume of patients with secondary progressive multiple sclerosis did not differ from that of placebo over 24 months, but lamotrigine seemed to cause early volume loss that reversed partially on discontinuation of treatment. Future trials of neuroprotection in multiple sclerosis should include investigation of complex early volume changes in different compartments of the CNS, effects unrelated to neurodegeneration, and targeting of earlier and more inflammatory disease. FUNDING: Multiple Sclerosis Society of Great Britain and Northern Ireland.