Objective: To clarify the clinical and long-term characteristic of each subtype of chronic inflammatory demyelinating polyneuropathy (CIDP). Methods: We evaluated data from 30 consecutive CIDP patients who met the criteria proposed by the European Federation of Neurological Societies and the Peripheral Nerve Society. Results: Patients were classified as having typical CIDP (t-‍CIDP) (10/30, 33%), multifocal acquired demyelinating sensory and motor (MADSAM) (12/30, 40%), DADS (4/30, 13%), sensory CIDP (3/30, 10%) or motor CIDP (1/30, 3%). Nerve conduction studies showed more prolonged distal motor latencies/F-wave latencies and slower motor nerve conduction in the typical CIDP group than in the MADSAM group. Intravenous immunoglobulin (IVIg) was effective in 80% (8/10) of t-‍CIDP, 100% (12/12) of MADSAM, 100% (4/4) of DADS, and 100% (3/3) of sensory CIDP cases. Maintenance therapy with immunoglobulin was administered in patients with t-‍CIDP (5/10, 50%), MADSAM (9/12, 75%), DADS (1/4, 25%), and sensory CIDP (2/3, 67%). There were no patients with CIDP, in whom CIDP subtype was transformed from the initial diagnosis during five years of follow-up. Discussion: Percentage of MADSAM was the most common phenotype in our cohort of CIDP patients, and IVIg/immunoglobulin maintenance was effective for MADSAM as well as t-‍CIDP in contrast to findings from the previous reports.

57-year-old woman with sequelae of cerebral infarction was admitted to our hospital because her left-sided hemiparesis was worsened. The right internal carotid artery (ICA) was not visualized by carotid duplex sonography and brain MRA. Arterial spin labeling (ASL) perfusion MR images showed reduced signals in the bilateral ICA territories at post labeling delay 1,525 ms. Her neurological symptoms improved on the day after hospitalization. On day 3, the bilateral ICAs were well visualized on MRA, while cerebral perfusion in the ICA territories appeared to be normalized on ASL. We diagnosed cervical ICA vasospasm, based on the findings of cervical MRA and cerebral angiography. Three months later, the recurrence of ICA vasospasm occurred. ASL was useful for the serial non-invasive evaluation of cerebral hemodynamics from the onset to improvement in a patient with ICA vasospasm.

A 31-year-old man visited our hospital due to experiencing severe headaches, vomiting, and hypesthesia in the left side of his body. He had no past illnesses and had had no severe headaches before. The symptoms started the day after receiving the coronavirus disease 2019 (COVID-19) vaccination with Tozinameran. An MRI revealed cerebral venous sinus thrombosis and high intensity (DWI & FLAIR) of the right thalamus. Anticoagulant therapy was initiated, and his symptoms improved gradually. The follow-up MRI showed recanalization in a large part of the occluded venous sinuses. Most of the coagulation tests were normal, except for slightly high value of D-dimer, and the polymerase chain reaction (PCR) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was negative. Further cases are needed to judge if there is some sort of relationship between the vaccination and the cerebral venous sinus thrombosis.

We report the case of a 51-year-old woman who developed neuromyelitis optica spectrum disorders (NMOSD) associated with primary biliary cholangitis (PBC). When she was 38 years old, she subacutely developed headache and urinary retention. A diffusion weighted image (DWI) on brain MRI showed high signal intensity in the left temporal white matter, and T₂ weighted image (T₂WI) on spine MRI showed high signal intensities in the spinal cord. After the initial event, follow-ups at 2, 6 and 9 months revealed that she developed neurological symptoms, and T₂WI on spine MRI showed high signal intensities in the cervical and thoracic regions of the spinal cord. On each episode, she was treated a course of intravenous methylprednisolone which resulted in improvement of her symptoms. At the age of 39 years, the serum levels of biliary enzymes began to elevate, and the serum levels were markedly elevated after the age of 40 years. When she was 40 years old, she developed optic neuritis of the right eye. At the age of 41 years, spine MRI again showed the cervical and thoracic spinal cord lesions. At the age of 51 years, she subacutely developed dizziness and urinary retention. DWI on brain MRI showed high signal intensities in the pons and medulla oblongata, and T₂WI on spine MRI showed longitudinally extensive high signal intensities in the spinal cord, specifically between the C3 and C5 vertebral levels. The serological tests for autoantibodies revealed positive anti-aquaporine 4 antibody (AQP4-Ab), positive anti-mitochondrial antibody subtype M2 (AM2-Ab) and positive anti-nuclear antibody, and the interleukin-6 (IL-6) level was elevated in the cerebrospinal fluid. Simultaneous occurrence of AQP4-Ab-positive NMOSD and AM2-Ab-positive PBC is extremely rare, and has never been reported in Japan. The present case is the first case with simultaneous occurrence of AQP4-Ab-positive NMOSD and AM2-Ab-positive PBC in Japan. We suspect that IL-6, plasmablast and cytotoxic T lymphocyte were involved with the occurrence of NMOSD with PBC in the present case.

An 86-year-old female was admitted to our hospital with acute progressive gait disturbance and cognitive impairment. Brain MR diffusion weighted imaging revealed abnormal high signal intensities in the bilateral hemispheres, dominantly in the frontal lobe. We first suspected acute encephalopathy due to Creutzfeldt–Jakob disease (CJD) from her clinical information. At the same time, we could not negate the possibility of Sjögren’s syndrome (SjS) -related encephalopathy based on the abnormal findings on brain MRI and positive anti-SS-A antibody in the serum. After consulting with an otorhinolaryngologist and a pathologist, biopsy of the salivary gland was performed with a strict precaution against infection of prion virus. Pathological examination of the biopsy specimen showed accumulation of many lymphocytes around the gland, which satisfied grade 4 in the Greenspan classification. A definite diagnosis of SjS was made based on the pathological findings, and intravenous high dose methylprednisolone followed by oral prednisolone were administered for suspected SjS-related encephalopathy. However, the neurological symptoms did not improve and we judged that SjS-related encephalopathy was unlikely. The poor response to steroid therapy and the presence of tau protein, strongly positive 14-3-3 protein and a codon 180: Val/Ile mutation in the cerebrospinal fluid finally led to a clinical diagnosis of genetic CJD. In-hospital cooperation in terms of infection prevention is important when performing invasive procedure in the case of suspected CJD to distinguish treatable encephalopathy.

A 67-year-old man presented slowly progressive weakness of the extremities visited our hospital. Nerve conduction study showed axonal neuropathy and needle electromyography showed neurogenic changes with denervation findings in multiple limb muscles. While he was diagnosed as Probable amyotrophic lateral sclerosis (ALS), which is defined by the Awaji criteria for diagnosis of ALS, he did not develop either respiratory muscle paralysis or bulbar palsy, which are characteristic symptoms of sporadic ALS. Genetic testing revealed a novel gene variant in senataxin (SETX), the causative gene of ALS4. We could not make a definite diagnosis of ALS4 because he had no relatives who could perform genetic testing (segregation study). However, we considered the variant can be pathogenic because it was not previously reported and absent in at least 1,000 healthy control individuals, the variant site was highly conserved in mammals, and it may impair the function of senataxin protein (in silico analysis).

An 11-year-old woman with myelin-oligodendrocyte glycoprotein (MOG) antibody developed cortical encephalitis twice, followed by acute disseminated encephalomyelitis (ADEM) and optic neuritis in one year. Although optic neuritis was refractory after corticosteroid therapy, plasma exchange was effective and complete remission was achieved. We considered that episodes of cortical encephalitis, ADEM and optic neuritis occurred in the present patient can be included in MOG IgG-associated disorders. Also, we recommend plasma exchange for refractory MOG IgG-associated optic neuritis, even in pediatric patient.

The case was a 30-year-old man. He had generalized convulsion after preceding meningitis symptoms and transferred to our emergency department. He was tentatively diagnosed with meningoencephalitis and Todd paralysis based on elevation of cell counts in cerebrospinal fluid and abnormal high signals in the right cerebral cortex on brain FLAIR-MRI, and admitted on the same day. After admission, treatment with antibiotics, dexamethasone, antiviral drug and anticonvulsants was started. Both his clinical symptoms and findings on MRI improved steadily, and then he was discharged on day 19. Subsequently, headache exacerbated again and an additional examination for his serum sample taken on first admission day revealed presence of anti myelin oligodendrocyte glycoprotein (MOG)-antibody, resulting in his diagnosis of anti-MOG antibody unilateral cerebral cortical encephalitis (MOG-UCCE) on day 42. Rehospitalization was planned for introduction of steroid therapy, but generalized convulsion recurred on day 44 and he was hospitalized again. MRI image revealed no FLAIR high signal and cerebrospinal fluid was almost normal, but his headache and mild hemiparesis and numbness on the left side deteriorated again. Therefore, he was treated with intravenous high dose methylprednisolone followed by oral steroids. His clinical symptoms gradually improved, and he was discharged with slight headache on day 71. After discharge, there has been no recurrence under continuation of low dose oral steroids for two years. This case shows the need to measure anti-MOG antibody and introduce steroid therapy in the early phase in a case of suspected MOG-UCCE in a young patient with meningoencephalitis accompanied by generalized convulsion and characteristic abnormal findings on FLAIR-MRI.

We present an adult case of mild encephalitis/encephalopathy with a reversible splenial lesion (MERS). A 26-year-old man with a family history of MERS presented to our hospital owing to dysarthria and dysesthesia of the right side of his body. The duration of these symptoms was approximately 4 hours. T₂ and diffusion weighted MRI showed high signal intensity lesions in the bilateral deep white matter. On a 3-week follow-up MRI, the lesions had completely disappeared. We attributed this clinical course and image findings to MERS. The patient had experienced similar symptoms at the age of 8 years old. Furthermore, his younger brother showed a similar clinical history and experienced a few recurrence events during the age of 9–16 years old. The mechanism of MERS remains controversial. However, similar to our case, there are some case reports with a family history. In addition, a previous report has confirmed the existence of a heterozygous variant in the myelin regulatory factor gene in patients with MERS. Some genetic factors may induce MERS, especially with extensive white matter lesions.