A possible role of low regulatory T cells in anti-acetylcholine receptor antibody positive myasthenia gravis after bone marrow transplantation.

BACKGROUND: Chronic graft-versus-host disease (GVHD) appears several months following allogenic hematopoietic stem cell transplantation (HSCT) and is clinically analogous to autoimmune disorder. Polymyositis is a common neuromuscular disorder in chronic GVHD, but myasthenia gravis (MG) is extremely rare. Hence, its pathophysiology and treatment have not been elucidated. CASE PRESENTATION: A 63-year-old man with a history of chronic GVHD presented with ptosis, dropped head, and dyspnea on exertion, which had worsened over the previous several months. He showed progressive decrement of compound muscle action potential in the deltoid muscle evoked by 3-Hz repetitive nerve stimulation, a positive edrophonium test, and elevated levels of serum anti-acetylcholine receptor antibodies, which suggested a diagnosis of generalized MG. No thymoma was found. Flow cytometric analysis revealed a remarkable depletion of peripheral Tregs (CD4+CD25highFOXP3+ cells, 0.24% of the total lymphocytes). Administration of prednisolone and tacrolimus was insufficient to alleviate his symptoms; however, the use of rituximab successfully improved his condition. CONCLUSIONS: Myasthenic symptoms appeared in the process of tapering prednisolone for the treatment of chronic GVHD, supporting the diagnosis of MG associated with chronic GVHD. The present case proposes a possibility that reduction of Tregs might contribute to the pathogenesis of MG underlying chronic GVHD. Immunotherapy with rituximab is beneficial for treatment of refractory MG and GVHD.

Cauda equina involvement in post-radiation lower motor neuron syndrome.

Post-radiation lower motor neuron syndrome (PRLMNS) is a rare neurological complication of radiation therapy and its pathogenesis is unclear. We herein report a patient with PRLMNS who developed leg weakness 17 years after craniospinal radiation as a treatment for suprasellar germinoma. The electrophysiological evaluation, via a novel magnetic stimulation method, indicated a prolonged cauda equina conduction time, suggesting focal demyelination of the nerve roots in the cauda equina. The distribution of the denervated muscles detected by magnetic resonance imaging was consistent with patchy motor nerve root lesions. These results support the hypothesis that PRLMNS originates from ischemic radiculopathy in the cauda equina.

Aquaporin-4 expression in distal myopathy with rimmed vacuoles.

BACKGROUND: Distal myopathy with rimmed vacuoles/hereditary inclusion body myopathy is clinically characterized by the early involvement of distal leg muscles. The striking pathological features of the myopathy are muscle fibers with rimmed vacuoles. To date, the role of aquaporin-4 water channel in distal myopathy with rimmed vacuoles/hereditary inclusion body myopathy has not been studied. CASE PRESENTATION: Here, we studied the expression of aquaporin-4 in muscle fibers of a patient with distal myopathy with rimmed vacuoles/hereditary inclusion body myopathy. Immunohistochemical and immunofluorescence analyses showed that sarcolemmal aquaporin-4 immunoreactivity was reduced in many muscle fibers of the patient. However, the intensity of aquaporin-4 staining was markedly increased at rimmed vacuoles or its surrounding areas and in some muscle fibers. The fast-twitch type 2 fibers were predominantly involved with the strong aquaporin-4-positive rimmed vacuoles and TAR-DNA-binding protein-43 aggregations. Rimmed vacuoles with strong aquaporin-4 expression seen in the distal myopathy with rimmed vacuoles/hereditary inclusion body myopathy patient were not found in control muscles without evidence of neuromuscular disorders and the other disease-controls. CONCLUSIONS: Aquaporin-4 might be crucial in determining the survival or degeneration of fast-twitch type 2 fibers in distal myopathy with rimmed vacuoles/hereditary inclusion body myopathy.

Diabetic striatal disease: clinical presentation, neuroimaging, and pathology.

BACKGROUND: Unilateral movement disorders and contralateral neuroimaging abnormalities of the striatum have been sporadically reported as a rare syndrome associated with diabetes mellitus. Despite characteristic imaging findings and clinical manifestations, the mechanism underlying this syndrome is still unclear. METHODS: Six patients with this syndrome were studied clinically and subjected to MRI neuroimaging; one underwent biopsy of the striatum, and another underwent additional MR spectroscopy at 3.0T and FDG-PET. RESULTS: Neuroimaging findings were characterized by a T1-hyperintense unilateral lesion restricted to the striatum, contralateral to the symptomatic limbs. The biopsied striatum contained patchy necrotic tissue, severe thickening of all layers of arterioles, and marked narrowing of vessel lumens. Hyaline degeneration of the arteriolar walls, extravasation of erythrocytes, and prominent capillary proliferation were also notable, together with lymphocytic infiltration and macrophage invasion. In one patient, PET examination revealed decreased accumulation of FDG in the lesion. The MR spectrum for the diseased striatum revealed a decrease in the NAA/Cr ratio (1.35), normal Cho/Cr ratio (1.22), and a peak for myoinositol, while the spectrum on the contralateral site revealed a decrease in the NAA/Cr ratio (1.48), increase in Cho/Cr (1.32), but no peak for myoinositol. CONCLUSION: The constellation of signs and symptoms and neuroimaging characteristics in previous reports and the six additional cases described here with neuropathological data and findings of MR spectroscopy appears unique enough to be termed "diabetic striatopathy." This syndrome appears in poorly controlled diabetics due to obliterative vasculopathy with prominent vascular proliferation, vulnerability to which is restricted to the striatum.

[A case of hypertrophic pachymeningitis, resolved by antimicrobial therapy].

A 65-year-old woman with diabetes mellitus and chronic otitis media developed headache, fever, and hoarseness, all of which did not responded to the oral antibiotics. As stiff neck and lower cranial nerve palsies appeared, bacterial meningitis was suspected. Neurological examination revealed the right hearing disturbance, right recurrent laryngeal nerve palsy, left sternocleidomastoid muscle atrophy and bilateral tongue atrophy. The CSF examination revealed mild pleocytosis and elevated protein, but no bacterial organism was cultured from the CSF. CT scans showed bilateral mastoiditis, and the right mastoid process and a posterior part of the petrous bone were eroded, indicating the exposed bony structures to the posterior fossa. MRI scans demonstrated the thickening of the dura mater of the posterior fossa and the right cerebellar tentorium. This is a rare example of bacterial pachymeningitis of the posterior fossa, the clinical symptoms and MRI findings of which resolved solely by antimicrobial agents without corticosteroid.

Intracranial invasive aspergillosis originating in the sphenoid sinus: a successful treatment with high-dose itraconazole in three cases.

We report three cases of intracranial aspergillosis originating in the sphenoid sinus in immunocompetent patients. The patients presented with an orbital apex syndrome in that a unilateral loss of vision and cranial nerve III palsy were seen in all cases and a contralateral involvement was also seen in one case. Despite the initial treatment with a conventional dose of itraconazole (ITCZ, 200 mg/day), the neurological deficits failed to improve and the granulomatous inflammation was not suppressed. Therefore, we treated with a combination of a high dose of ITCZ at 500-1000 mg/day (16-24 mg/kg/day) and amphotericin B (AMPH-B) at 0.5 mg/kg/day, in conjunction with a pulse dose of methylprednisolone at 1000 mg/day. Two cases responded favorably in that the ocular movements completely recovered, and their maximum serum concentrations of the hydroxy ITCZ were 7816 ng/ml and 5370 ng/ml. However, the other case worsened, despite ITCZ treatment at 16 mg/kg/day, and the serum concentration of the hydroxy ITCZ was 3863 ng/ml. The surgical decompression of the cavernous sinus via an extradural approach was performed, and the dose of ITCZ was increased to 24 mg/kg/day. The resulting serum concentration of the hydroxy ITCZ was 4753 ng/ml, and the outcome of this case has been favorable. These results suggest that a high blood level of the hydroxy ITCZ (more than 4500 ng/ml) is a prerequisite for the successful treatment of intracranial aspergillosis and that the combination treatment of ITCZ with AMPH-B would be preferred. The concomitant use of steroid and/or surgical decompression should be considered, if the invasiveness is not well-controlled in spite of intensive medical therapy.