A 37-old-male with a history of early childhood mental retardation was admitted to our hospital. He experienced recurrent syncopes at 23 years old, and at age 35 gait disturbance and hearing impairment developed gradually and worsened over time. His grandparents were in a consanguineous marriage. He was of short stature and absent of tendon xanthomas. Neurological examinations revealed scanning speech, dysphagia, right sensorineural hearing loss, spasticity in both upper and lower extremities, and spastic gait. Tendon reflexes were brisk throughout, and Babinski and Chaddock reflexes were both positive bilaterally. Laboratory tests revealed elevated lactate and pyruvate concentrations in both serum and cerebrospinal fluid. Fluid attenuated inversion recovery magnetic resonance imaging showed high intensity lesions in the bilateral cerebellar hemispheres, pyramidal tracts in the brainstem, and internal capsules symmetrically. Brain magnetic resonance spectroscopy measurements revealed an elevated lactate/creatine plus phosphocreatine ratio and a decreased N-acetyl-aspartate/creatine plus phosphocreatine ratio in the cerebellum. At this point, mitochondrial diseases, particularly myoclonic epilepsy with ragged-red fibers (MERRF), to be the most likely cause. We performed a biopsy of his left biceps brachii muscle, showing variations in fiber size with occasional central nuclei and very few ragged-red fibers. Blood mitochondrial respiratory enzyme assays showed normal values with elevated citrate synthase activity, and mitochondrial DNA analyses for MERRF revealed no pathogenic mutations. We then explored other possibilities and detected an elevated serum cholestanol concentration of 20.4 μg/ml (reference value <4.0) and genetic analysis by direct sequencing method disclosed a novel frame-shift mutation (c. 43_44delGG) in CYP27A1 gene exon1, leading to a diagnosis of cerebrotendinous xanthomatosis (CTX). This case emphasizes importance of awareness of CTX as a possibility when patients present with clinical phenotypes mimicking mitochondrial diseases, but with negative results for muscle pathology or genetic analyses. The measurements of serum cholestanol concentrations might be useful in diagnosing such atypical cases.

We report the case of a 42-year-old man with chronic hepatitis B virus infection who developed weakness and paresthesia in the extremities 2 months after administration of pegylated interferon (Peg-IFN)α-2a. Nerve conduction studies conducted 6 months after onset showed abnormal temporal dispersions in both tibial nerves. We diagnosed chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) resulting from treatment with Peg-IFNα-2a. Neurological symptoms were prolonged despite suspension of the treatment. Subsequent treatment with intravenous immunoglobulin improved both clinical symptoms and temporal dispersion. IFNα-induced CIDP is rare, but can reportedly progress even after interruption of IFN-α without immunotherapy. Patients presenting with polyneuropathy after initiation of IFN-α thus require close attention.

A 64-year-old man with fever, appetite loss, and pain in the back of the neck visited our hospital. We diagnosed him as having bacterial meningitis because of pleocytosis of the cerebrospinal fluid, and started treatment with antibiotics. Multiple cerebral infarcts were found on brain MRI. We suspected that the origin of the bacterial meningitis was infective endocarditis, and administered Cefepime and Gentamicin according to the guidelines for treatment of infective endocarditis. Three days later, he became drowsy and had myoclonus and flapping of the extremities. An electroencephalograph showed generalized periodic discharge and a triphasic wave pattern. We thought that the cause of disturbance in consciousness was Cefepime-induced encephalopathy, and stopped administration of Cefepime. A few days later, he became clear, and the myoclonus and flapping disappeared. It was difficult to distinguish between non-convulsive status epilepticus and Cefepime-induced encephalopathy. However, since stopping Cefepime treatment had made the patient clear, we diagnosed his condition as Cefepime-induced encephalopathy, which often occurs in patients with renal or liver dysfunction, or in brain infarction or meningitis, which results in blood–brain barrier disruption. Thus, care should be taken when administering Cefepime to such patients.

A 55-year-old man was admitted to our hospital because of acute onset of diplopia and gait disturbance. On admission, ophthalmoplegia, ataxia and areflexia were observed. He was diagnosed with Fisher syndrome and given intravenous immunoglobulin therapy from day 6 to day 10 after disease onset. After treatment, ophthalmoplegia and ataxia began to improve. However, he developed taste impairment on day 13 and right hemifacial weakness on day 16 after onset. A blink reflex test revealed right facial nerve impairment. On day 42 after onset, facial weakness and taste impairment remitted, and the blink reflex test result was normalized without additional treatment. Although it has been known that 10% of patients with Fisher syndrome complicated by delayed facial nerve palsy, the mechanism of the facial nerve palsy has not been elucidated. Therefore, this is a significant report to describe delayed facial nerve palsy combined with taste impairment and successive recordings of blink reflex and facial nerve conduction in a patient with Fisher syndrome.

We report a 39-year-old woman with slowly progressive spastic gait and paresthesia in the lower extremities. Cervical spinal MRI revealed high intensity in the dorsal column from vertebrae C2 to C7. Laboratory findings showed normal vitamin B12 and low serum copper level. By lifestyle history taking, we noticed her extreme unbalanced diet of having 15–20 oysters everyday over 5 years. Then we considered that zinc excess caused copper deficiency myelopathy. We needed to pay attention to copper and zinc level if the patient has a symptom resembling subacute combined degeneration of spinal cord with normal serum vitamin B12.

We report a 28-year-old woman with the overlap of Fisher syndrome and pharyngeal-cervical-brachial variant of Guillain-Barré syndrome associated with urinary retention and constipation. She showed total ophthalmoplegia, dysphagia, dysarthria, upper extremity weakness, cerebellar ataxia, slightly diminished superficial sensations in her hands and feet, urinary retention and constipation 14 days after preceding infection. Laboratory data showed elevations of antiganglioside antibodies to GT1b, GD1b, GQ1b, GD3 and GT1a in the IgG subclass. There was slight elevation of protein with no pleocytosis in cerebrospinal fluid. After administration of intravenous immunoglobulin (IVIg), only the titer of antiganglioside antibody to GQ1b was decreased, and she showed rapid improvement in dysphagia, urinary retention and constipation, and slow recovery in ophthalmoplegia and cerebellar ataxia. The elevations of antiganglioside antibodies to GQ1b may be pathologically related to autonomic involvement such as urinary retention and constipation in that IVIg seems to be effective. The present case suggests that GQ1b may also locate in the autonomic nerve that plays bladder and defecation functions, and that incidence of neurological symptoms and the response of treatment may differ according to each GQ1b localization.

This report concerns a case of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with frequent treatment-dependent relapses. A 75-year-old male presented with a 2-month history of progressive weakness of the limbs with no sensory symptoms. Neurological examination revealed normal cranial nerves, MRC grade 4 power in the proximal and distal muscles of the limbs, and generalized areflexia. However, the sensory examination results, serum immunoelectrophoresis, anti-HIV antibody, and vitamins B1 and B12 levels were normal. Cervical MR imaging was unremarkable. Cerebrospinal fluid showed albuminocytologic dissociation. Nerve conduction studies demonstrated prolonged distal latencies in the bilateral median nerves and left ulnar nerve. Treatment with intravenous immunoglobulin (IVIg) infusion resulted in a marked improvement. Thereafter, the patient had been treated with repeated IVIg to maintain motor function. Subsequently, the patient fulfilled the EFNS/PNS diagnostic criteria for pure motor form of definite CIDP. Treatment with ciclosporin with the plasma trough level of 60–150 ng/ml reduced the frequency of IVIg. However, renal function began to deteriorate 94 months after the initiation of ciclosporin. The calcineurin inhibitor was replaced with mycophenolate mofetil 1,500 mg, which significantly increased the interval between infusions without further renal impairment. Therefore, mycophenolate may represent an effective alternative treatment for some IVIg-dependent CIDP patients.

A 64-year-old woman developed acute paralysis of glossopharyngeal, vagus, accessory, and hypoglossal nerves on the left side after pain in the head and the left ear and throat. Cerebrospinal fluid examination revealed lymphocytic pleocytosis and elevated protein concentration. Varicella-zoster virus (VZV)-DNA was detected by PCR from cerebrospinal fluid. The diagnosis of lower cranial polyneuropathy due to VZV reactivation was made. After oral administration of an anti-viral agent and steroid, all symptoms and signs dramatically improved. Notably, there was no evidence of cutaneous or mucosal rash during the whole course of the disease. VZV reactivation should be included in the differential diagnosis of acute lower cranial polyneuropathy, especially with pain in the ear and throat, even without cutaneous or mucosal rash.

An 83-year-old man with chronic renal failure was referred to our hospital because of subacute progressive right hemiparesis. A brain MRI showed high-intensity lesions in bilateral middle cerebellar peduncles and white matter of the left frontal lobe on T₂-weighted images. The lesions increased gradually, so we suspected a brain tumor because ¹H-MRS images showed elevated Cho and decreased NAA, and also pathologic findings of the brain biopsy suggested glioblastoma. However, JC virus (JCV) in cerebrospinal fluid was revealed highly positive by PCR. So we reconsidered pathologically and finally found bizarre astrocytes which were infected with JCV in immunohistochemical studies and we diagnosed progressive multifocal leukoencephalopathy at last. Then we medicated with mefloquine and mirtazapine, and the JCV in cerebrospinal fluid disappeared, without new MRI lesions. This is a rare case in respect of the background of the patient and the clinical course.