B cell aplasia and hypogammaglobulinemia after carbamazepine treatment.

Although immunosuppressive effects of antiepileptic drug are well known, serious complications of antiepileptic drug are rare. We report a case of hypogammaglobulinemia associated with aplasia of B lymphocytes after carbamazepine treatment. Despite repeated intravenous immunoglobulin replacement therapy, this condition persisted for more than three months. The present case suggested that routine monitoring of the blood cell count and serum levels of immunoglobulin are important in patients treated with carbamazepine, and a lymphocyte subpopulation study is valuable in cases of hypogammaglobulinemia.

Development of Isaacs' syndrome following complete recovery of voltage-gated potassium channel antibody-associated limbic encephalitis.

Autoantibodies against voltage-gated potassium channels (VGKC-Abs) are associated with acquired neuromyotonia (Isaacs' syndrome) and related disorders such as Morvan's syndrome and some cases of limbic encephalitis. The mechanisms underlying the various phenotypes induced by VGKC-Abs are not fully understood. Recently, we reported a case of LE with VGKC-Abs accompanied by severe intestinal pseudo-obstruction and thymoma. Thymectomy and immunosuppressive therapy induced dramatic clinical improvement of LE symptoms, and VGKC-Abs titers decreased from 1254 pM to 549 pM (normal>100 pM). Seventeen months later, the patient developed progressive generalized muscle cramping, paresthesias in his lower extremities, excessive sweating, and severe constipation. There was no recurrence of the LE. Electromyography showed fasciculation potentials and myokymic discharges, and the plasma VGKC-Abs titer was again elevated to 879 pM. Here we report a case of Isaacs' syndrome after complete remission of LE with VGKC-Abs that may provide an insight into a possible link among VGKC-Abs associated syndromes.

Potassium channel antibody-associated encephalitis with hypothalamic lesions and intestinal pseudo-obstruction.

A subgroup of limbic encephalitis is associated with antibodies against voltage-gated potassium channels (VGKC), and responds well to immuno-modulating therapies. Anti-VGKC antibodies are also found in Isaacs' syndrome and Morvan's syndrome, both of which are sometimes complicated by thymoma. We describe a 52-years-old man with limbic encephalitis, thymoma, and anti-VGKC antibodies, who presented with autonomic dysfunctions such as severe intestinal pseudo-obstruction, hyperhidrosis and hypertension. Thymectomy and corticosteroid therapy remarkably improved his symptoms. Brain magnetic resonance imaging showed hypothalamic lesions, in addition to the bilateral involvement of the medial temporal lobes. This patient had severe autonomic dysfunctions resembling those of Morvan's syndrome. This case may represent a subgroup of VGKC-antibody associated syndromes with a wide spectrum of symptoms, including Isaacs' syndrome, Morvan's syndrome, and limbic encephalitis.

Intradural extramedullary tuberculoma of the thoracic spine: paradoxical response to antituberculous therapy.

Intradural extramedullary tuberculoma of the spinal cord (IETSC) is a rare complication of tuberculosis, which can occur as a paradoxical response to antituberculous therapy. A 46-year-old woman with tuberculosis meningitis developed an acute sensory disturbance and paraplegia eight weeks after the antituberculous treatment was started. MRI revealed a cystic lesion at the Th 2 and 3 vertebrae levels, and continuous dural thickening. Laminectomy was performed; soft granulomas were unexpectedly observed inside the dura matter. After the operation, the patient experienced progressive improvement in motor strength. IETSC should be known as rare but possible complication of tuberculous meningitis.

Two different clinical phenotypes of Creutzfeldt-Jakob disease with a M232R substitution.

OBJECTIVE: To describe the clinical features of Creutzfeldt-Jakob disease with a substitution of arginine for methionine (M232R substitution) at codon 232 (CJD232) of the prion protein gene (PRNP). PATIENTS AND METHODS: We evaluated the clinical and laboratory features of 20 CJD232 patients: age of onset, initial symptoms, duration until becoming akinetic and mute, duration until occurrence of periodic sharp and wave complexes on EEG (PSWC), MRI findings, and the presence of CSF 14-3-3 protein. Immunohistochemically, prion protein (PrP) deposition was studied. RESULTS: None of the patients had a family history of CJD. We recognized two clinical phenotypes: a rapidly progressive type (rapidtype) and a slowly progressive type (slow-type). Out of 20 patients, 15 became akinetic and mute, demonstrated myoclonus, and showed PSWC within a mean duration of 3.1, 2.4, and 2.8 months, respectively (rapid-type). Five showed slowly progressive clinical courses (slow-type). Five became akinetic and mute and four demonstrated myoclonus within a mean duration of 20.6 and 15.3 months, respectively, which were significantly longer than those in the rapid-type. Only one demonstrated PSWC 13 months after the onset. Diffuse synaptic-type deposition was demonstrated in four rapidtype patients, and perivacuolar and diffuse synaptic-type deposition in two, and diffuse synaptic-type deposition in one slow-type patient. Three of 50 suspected but non-CJD patients had the M232R substitution. CONCLUSIONS: Patients with CJD232 had no family history like patients with sCJD, and showed two different clinical phenotypes in spite of having the same PRNP genotype. More studies are needed to determine whether M232R substitution causes the disease and influences the disease progression.

Anti-GQ1b antibody does not affect neuromuscular transmission in human limb muscle.

Anti-ganglioside GQ1b antibody induces neuromuscular blocking on mouse phrenic nerve-diaphragm preparations. Several reports suggest that patients with this antibody show abnormal neuromuscular transmission in the facial or limb muscles, but limb muscle weakness is unusual in Miller Fisher syndrome that is often associated with anti-GQ1b antibody. To determine whether anti-GQ1b sera affect neuromuscular transmission in human limb muscles, axonal-stimulating single fiber electromyography was performed in the forearm muscle of seven patients with anti-GQ1b antibody. All showed normal jitter and no blocking. Anti-GQ1b antibody does not affect neuromuscular transmission in human limb muscles. The different findings in mouse and human may be explained by the extent of expression of GQ1b on the motor nerve terminals in the muscle examined.

Is excitation-contraction coupling impaired in myasthenia gravis?

OBJECTIVE: To investigate whether excitation-contraction (E-C) coupling of muscle is impaired in patients with myasthenia gravis (MG). METHODS: In 51 patients with generalized MG and 35 normal subjects, compound muscle action potentials (CMAPs) of the abductor pollicis brevis, and movement-related potentials using an accelerometer placed at the thumb tip were simultaneously recorded after median nerve stimulation at the wrist. The E-C coupling time (ECCT) was estimated by a latency difference between CMAP and movement-related potential. Antibodies against acetylcholine receptor (AChR), ryanodine receptor (RyR), and muscle specific receptor tyrosine kinase (MuSK) were measured by immunoassays. RESULTS: The mean ECCT was significantly longer in patients with MG (mean+/-SEM; 2.79+/-0.1 ms; p=0.002) than in normal controls (2.52+/-0.1 ms). Among MG patients, the mean ECCT was longer for patients with thymoma than for those without it (P=0.04), and was shorter for patients treated with FK506 (an immunosuppressant and also an enhancer of RyR related Ca(2+) release) than for those not receiving this treatment (p=0.04). ECCT had no significant correlation with anti-AChR, anti-RyR, or anti-MuSK antibodies. CONCLUSIONS: In MG, E-C coupling appears to be impaired, particularly in patients with thymoma, and FK506 possibly facilitates E-C coupling. SIGNIFICANCE: The functional implication of impaired E-C coupling is not established, but it may contribute to muscle weakness in patients with MG.

[Indications, efficacies and periopertive problems of thymectomy in non-thymomatous myasthenia gravis].

A recent evidence-based review failed to show conclusive benefits of thymectomy in non-thymomatous MG patients, and only recommended thymectomy as an option to increase the probability of remission or improvement. Furthermore, it is a matter of another controversy whether thymectomy is beneficial in ocular MG and also late-onset MG patients without thymoma. We reviewed the clinical course and outcomes of ocular MG and late-onset MG patients in a retrospective cross-sectional multi-center survey conducted in Japan. Our data shows that thymectomy may prevent, or limit the severity of, the generalization of the disease but do not improve ocular symptoms. For late-onset MG, thymectomy is a potentially effective treatment. Another problem is that postoperative course can fluctuate and sometimes postoperative respiratory failure and myasthenic crisis may occur. We described that perioperative steroid therapy is feasible and have clinical benefits for generalized MG with fluctuating symptoms. Mainly after thymectomy, tacrolimus or cyclosporine therapy may allow steroid daily doses to be reduced in MG patients who intended to reduce concomitant steroid use.

High-dose intravenous immunoglobulin for the treatment of MuSK antibody-positive seronegative myasthenia gravis.

We treated two patients with anti-muscle specific tyrosine kinase (MuSK)-antibody positive seronegative myasthenia gravis (MG) with high-dose intravenous gammaglobulin (IVIg) and evaluated their clinical courses. Both patients were Japanese women, MuSK-positive seronegative MG, and were unresponsive to conventional treatments, including thymectomy, steroids, and tacrolimus. The patients required frequent hospitalization for plasmapheresis. In case 1, a 45-year-old woman, it was difficult to obtain blood access for plasmapheresis. High-dose IVIg, 400 mg/kg per day for 5 days, was administered in cases 1 and 2. In both cases, clinical improvement was observed 3 days after the start of IVIg therapy and lasted for 2 to 3 months. We propose that IVIg therapy is an effective treatment for MuSK-positive seronegative MG, when conventional treatments have failed.