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Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a most common chronic immune-mediated demyelinating neuropathy, and includes a number of clinical subtypes. The major phenotype is "typical CIDP", which is characterized by symmetric polyneuropathy and "proximal and distal" muscle weakness. During the historical changes in the concept of CIDP, multifocal motor neuropathy, anti-myelin-associated glycoprotein (MAG) neuropathy, and autoimmune nodopathy have been excluded. Currently CIDP is considered as a syndrome including typical CIDP and CIDP variant such as distal CIDP and multifocal CIDP. In 2021, the international guideline of diagnosis and treatment for CIDP, European Academy of Neurology (EAN)/Peripheral Nerve Society (PNS) Guideline, was published. This review article introduces the putline of the guideline with medical-social situation in Japan. The diagnosis of CIDP is based on (1) phenotype of typical CIDP or variant, (2) electrophysiologic evidence of peripheral nerve demyelination, and (3) exclusion criteria. The first-line treatments are corticosteroids or immunoglobulin therapy, and plasma exchange should be considered if the 2 treatments were not effective sufficiently. This guideline recommends intravenous or subcutaneous immunoglobulin as a maintenance therapy, and suggests other immune-suppressive agents. In the near future, new treatment with biologics, such as monoclonal antibodies against neonatal Fc receptors, complements, and CD19/20 will be approved.

A 62-year-old Japanese man with a history of smoking, hypertension and paroxysmal atrial fibrillation presented sudden-onset disturbance of consciousness. He had a fluctuating consciousness, transient apnea, and vertical gaze palsy. Brain diffusion-weighted MRI showed hyperintense signals in the rostral midbrain and bilateral paramedian thalami, and the diagnosis of midbrain and bilateral thalamic infarction was made. The midbrain lesion corresponded with midbrain V sign, a characteristic finding of this infarction. Although there are several other deseases causing bilateral thalamic lesion, this sign is very helpful in distinguishing the disease from others. On the other hand, CT angiography visualized another variant of thalamoperforating arteries instead of Artery of Percheron (AOP), the common variant in bilateral thalamic infarction. This case indicates that other anatomical variants of thalamoperforating arteris besides AOP could cause this infarction.

This review described current status and perspectives of treatment for immune-mediated neuropathies, such as Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy (CIDP), multifocal motor neuropathy, and demyelinating neuropathy with anti-MAG neuropathy. corticosteroids, immunoglobulin therapy, and plasmapheresis are conventional treatments for these neuropathies, but the responsiveness to the treatments significantly differ among the disorders. Promising new treatment options include anti-complement monoclonal antibody (Eculizumab, anti-C5) for Guillain-Barre syndrome, and rituximab (anti-CD20) for anti-MAG neuropathy. For CIDP, different treatments would be required according to the clinical subtypes; typical CIDP and asymmetric variabt). For multifocal neuropathy, maintainance treatment with immunoglobulin is necessary.

Wide-spread fasciculations are prominent clinical features in patients with amyotrophic lateral sclerosis (ALS), specifically seen in ALS among disorders with neurogenic muscle atrophy. Fasciculations frequently arise from the motor nerve terminals, and the hyperexcitability of motor axons appears to constitute the pathophysiology of the disease. Neurophysiologic investigations of the upper and lower motor neurons/axons have shown increased excitability. The altered excitability is supposed to relate to motor neuron death. Based on these findings, a clinical trial of mexiletine (non-selective sodium channel blocker) is ongoing.

Fisher syndrome has been regarded peculiar inflammatory neuropathy with ophthalmoplegia, ataxia, and areflexia, whereas Bickerstaff brainstem encephalitis has been considered pure central nervous system disease characterized with ophthalmoplegia, ataxia, and consciousness disturbance. Both disorder share common features including preceding infection, albumin-cytological dissociation, and association with Guillain-Barre syndrome. The discovery of anti-GQ1b IgG antibodies further supports the view that the two disorder represent a single disease spectrum. Currently Bickerstaff brainstem encephalitis can be regarded as a variant of Fisher syndrome with central nervous system involvement.

A 20-year-old previously healthy man presented with prolonged consciousness alteration and severe hypertonia in the extremities after minor head trauma. Laboratory blood tests and cerebrospial fluid (CSF) tests were unremarkable except for an elevated CSF glycine concentratons. Brain MRI revealed hypoplasia of corpus callosum, enlargement of lateral cerebral ventricle and high signal intensity in the bilateral white matter on T(2) weighted images. On fluid attenuated inversion recovery images, the signal intensity resembled that of CSF in the central areas of T(2) alterations, surrounded by a rim of hyperintensity. These characteristic history and the results of brain MRI and CSF, the diagnosis of vanishing white matter disease (VWMD) was made. VWMD is a rare autosomal recessive leukoencephalopathy which typically begins during infancy or early childhood with a chronic progressive neurological deterioration with cerebellar ataxia and spasticity. Recently, milder variants of the disease with adult onset have been reported. VWMD should be included in the differential diagnosis of leucoencephalopathy in young adults.

Fasciculation is a characteristic feature of ALS. Nerve excitability studies have shown increased persistent sodium currents and reduced potassium currents in motor axons of ALS patients, both of which lead to axonal hyperexcitability and thereby generation of fasciculations. The present study was undertaken to investigate whether abnormal axonal excitability indices are correlated with survival in ALS patients. A total of 112 consecutive patients with sporadic ALS were followed-up until endpoint (death or tracheostomy). Univariate analyses revealed longer strength-duration time constant (SDTC) was associated with a shorter survival. In multivariate analyses using the Cox proportional hazard model, onset age>60 years and longer SDTC were strong predictors of shorter survival. Assuming that SDTC depends on nodal persistent sodium conductances, our results showed that an increased persistent sodium current is strong and independent predictor for short survival of ALS patients. These findings support the hypothesis that membrane hyperexcitability would contribute to motor neuronal death in ALS.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is classified into typical type that is characterized by proximal weakness and atypical type that include demyelinating acquired distal symmetric (DADS) type. DADS type CIDP is characterized by slowly progressive clinical course, motor and sensory involvement dominant in the leg and resistance to therapy. We report the case of a 72 year-old man with DADS type CIDP, who have dysesthesia and weakness dominant in distal of limbs. Disease progression was resistant to therapy for prednisolone and intravenous immunoglobulin, but slowly progressive for 4 years. Subacute exacerbation that was accompanied by proximal weakness was occurred at 4 years later from onset. Nerve conduction study revealed markedly prolonged distal latencies and slowing of conduction velocities. Double filtration plasmapheresis improved symptom, after oral prednisolone kept remission. This case had characteristic of DADS type CIDP at the onset, but changed into typical CIDP also for the therapy in the clinical course. This case indicate the multiplicity of CIDP.

Crow-Fukase syndrome, also called POEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes) syndrome, is a rare cause of demyelinating and axonal mixed neuropathy with multiorgan involvement. The pathogenesis of Crow-Fukase syndrome is not well understood, but overproduction of vascular endothelial growth factor (VEGF), probably mediated by monoclonal proliferation of plasma cells, is likely to be responsible for most of the characteristic symptoms. There is no established treatment regimen. In appropriate candidates, high-dose chemotherapies with autologous peripheral blood stem cell transplantation is highly recommended, because this treatment could result in obvious improvement in neuropathy as well as other symptoms, with a significant decrease in serum VEGF levels. Indication of this treatment has not yet been established, and long-term prognosis is unclear at present. Thalidomide should be considered for patients who are not indicated for transplantation therapy. Treatments that should be considered as future therapy include lenalidomide, bortezomib, and anti-VEGF monoclonal antibody (bevacizumab).

There are significant advances in immune-modulating treatments for Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP) in the past 20 years. GBS, however, is still a serious disease with a mortality rate of 8% and 20% of the patients being unable to walk independently a year after onset For CIDP and related disorders such as multifocal motor neuropathy, and demyeinating neuropathy with anti-myelin-associated-glycoprotein (MAG) antibody, treatments should be based on individual pathophysiology. Rituximab could be a promising agent for the subtypes of CIDP refractory to conventional immune treatments. Crow-Fukase syndrome is a rare cause of demyelinating neuropathy with multiorgan involvement Overproduction of vascular endothelial growth factor (VEGF), probably mediated by monoclonal proliferation of plasma cells, is likely to be responsible for most of the characteristic symptoms. There is no established treatment regimen for Crow-Fukase syndrome. In appropriate candidates, high-dose chemotherapies with autologous peripheral blood stem cell transplantation is highly recommended, because this treatment could result in obvious improvement in neuropathy as well as other symptoms. Indication of this treatment has not yet been established, and long-term prognosis is unclear at present. Treatments that should be considered as future therapy against Crow-Fukase syndrome include thalidomide, and anti-VEGF monoclonal antibody (bevacizumab).

To examine the validity of electrodiagnostic tests to help diagnosis and to evaluate disease activity of juvenile atrophy of unilateral upper limb (Hirayama's disease), we reviewed the results of nerve conduction studies, motor unit number estimates, electromyography, and somatosensory evoked potentials in consecutive 38 patients. There was selective involvement of the C8-T1 myotomes, in which motor unit loss was more prominent in the abductor digiti minimi than in the abductor pollicis brevis muscles, and F wave persistency was decreased out of proportion to the motor unit loss. These findings may help diagnosis. With respect to the disease activity and treatment, denervation potentials in the flexor carpi radialis muscle were more frequent in patients with shorter disease duration than those with longer duration. Median F wave persistency was greater in patients treated with neck brace than in patients without the treatment. These parameters can monitor the disease activity and efficacy of treatment.

We described a-44-year old male patient with Isaacs' syndrome occurring 8 months before the recurrence of malignant thymoma. Electrophysiological examination suggested that spontaneous muscle activities were generated at the distal terminals of the motor nerves. Double filtration plasmapheresis alleviated the symptoms of neuromyotonia for a short term. Administration of valproic acid had more prolonged effects lasting for 2 months until his death from relapsed thymoma. Our results support that autoimmune mechanisms, especially humoral factors, are playing an important role in the pathogenesis of Isaacs' syndrome and that anti-convulsants therapy is important.

We report a 23-year-old woman, who had a relapsing-remitting multiple mononeuropathy with multifocal nerve enlargement. The patient was characterized by asymmetrical, marked enlargement of multiple nerves in the arms (median and ulnar nerves) and neck (accessory nerve) bilaterally. Sequential nerve conduction studies revealed persistent demyelinative abnormalities, especially across the segment of nerve thickening. The MRI of the proximal arm confirmed the markedly enlarged median and ulnar nerves which showed high signal intensity on T2-weighted images and partial enhancement after administration of gadolinium. We consider that the patient had the clinical features of "multifocal pseudohypertrophic neuropathy" described by Adams et al, and that chronic demyelination and inflammation associated with impairment of the blood-nerve barrier might be underlying mechanisms.

We studied the effect of double filtration and immunoadsorption plasmapheresis in Guillain-Barré syndrome retrospectively in 70 patients. Thirty three patients had plasmapheresis, of whom 23 had double filtration and 10 immunoadsorption. The rest of 37 patients consisted of a control group. Clinical disability was evaluated using the functional grading scale by Hughes. In patients having a maximum disability of grade 4 and 5, the double filtration plasmapheresis group showed statistically significant improvement at 3 months after the treatment. There was no significant difference in prognoses between the immunoadsorption plasmapheresis and control groups. In mildly-illed patients having grade 2 and 3, the prognoses were not different between the three groups. In Guillain-Barré syndrome, double filtration plasmapheresis, as well as well-established plasma exchange, had benefit for severely-illed patients.

We investigated excitability of cervical lower motoneurons in 18 patients with juvenile muscular atrophy of the distal upper limb (Hirayama's disease), by F wave analysis and electrophysiological estimation of the number of motor units in the abductor pollicis brevis muscles of the affected side. In all the 18 patients, F wave persistencies and numbers of motor units were decreased, whereas amplitudes of single motor unit potentials were increased, compared to those of age-matched normal controls. Patients in a progressive phase showed markedly decreased F wave persistencies, overwhelming the degree of decreases in numbers of motor units. In half of them, F waves were significantly increased in number during neck flexion. On the other hand, patients treated with neck brace and patients having stabilized symptoms with longer duration showed F wave persistence reduction corresponded to the degree of the motor unit loss, and no changes in F wave persistencies in a posture of neck flexion. These results suggest that the disorder is characterized by decreased excitabilities of survived cervical anterior horn cells, as well as denervation and reinnervation, presumably resulting from local compression or circulatory failure by anterior shift of the posterior dural wall during neck flexion.

We found an electromyographical proof of reconstruction of the motor nerve terminals following hyperbaric oxygen therapy. A 38-year-old man who had been partially recovered for thirty four months from acute onset paraplegia following a gastrointestinal infection developed progressive muscular atrophy and weakness of the lower limbs, and was first admitted to our hospital. Cerebrospinal fluid examination was normal and nerve conduction studies showed small compound muscle action potentials without an evidence of segmental demyelination. There were ample fibrillation potentials on electromyography. Single fiber electromyography (SFEMG) showed increased fiber density, abnormal jitter and blockings without neurogenic jitter, which were similar to findings in post-poliomyelitis syndrome. He was treated by hyperbaric oxygen consisting of two hour exposures to pressures of two atmospheres breathing 100% oxygen. These exposures continued for a month daily, and thereafter once a week for one year. Clinical improvement of the weakness and a decrease in amount of fibrillation potentials occurred on and after a month after treatment. We found significant changes on SFEMG a year later. There were increased fiber densities and decreased mean values of consecutive differences. These changes indicate diminished degeneration and enhanced regeneration of the terminal axons. We think that hyperbaric oxygen has a beneficial effect on oxygen metabolism of remaining motoneurons which may not be able to maintain excessive metabolic demands of all their sprouting axons.

This report is concerning a case of acute spontaneous paralysis of the posterior interosseous nerve (P.I.O.N.), possibly caused by twists in the nerve trunk, in a 23-year-old woman. The subject felt a tingling pain over the lateral epicondyle of the right forearm when grasping and lifting a basin, and noticed that the fingers of the right hand could not be extended three days later. The fingers of the left hand also experienced paralysis 3 months after the first injury when she pronated and extended left forearm. Neurological examination revealed bilateral P.I.O.N. paralysis. When, after a period of time, the bilateral P.I.O.N. paralysis had not improved, surgical exploration of both P.I.O.N. was performed. It revealed that the right P.I.O.N. underwent a severe constriction at 2 cm proximal to the superficial portion of the supinator muscle, and that the proximal portion of the right nerve was swollen. The constricted portion of the right nerve was resected 5 mm in length, and nerve suturing was performed. The left P.I.O.N. was also constricted at the same location, and was found to be a sausage-like neurinoma with two constrictions. In the histological examination of the right resected P.I.O.N., edema of the interstitial tissue and a great number of regenerating cluster formations, including swollen axons, were observed proximal to the constriction. Distal to this, severe Wallerian degeneration was found. These histological findings were the same as those of chronic compression neuropathy. The authors reviewed and analysed reports on 20 other cases of P.I.O.N. paralysis that had compressions at 2 cm proximal to the superficial portion of the supinator muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

We reported a patient with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), presenting localized radiculopathy as an initial symptom. The patient, a 38-year-old man, developed muscle atrophy of right shin and calf. In April 1988, neurological examination revealed decreased superficial sensation and muscle atrophy in right L-4 distribution. MRI of the lumbar spinal cord and myelography were negative. In April 1989, he was admitted to Chiba University Hospital. There were slight weakness of right ankle extension and flexion, muscle atrophy of bilateral shin and calf (that of the right leg was more marked), decreased sensation of polyneuropathy type in all modalities and generalized hypo- or a-reflexia. Nerve conduction study revealed marked prolongation of F response and focal conduction block in various site. The CSF was acellular and total protein was 177 mg/dl. Sural nerve biopsy disclosed decreased number of large myelinated fibers and scattered thin myelinated fibers. This case indicates that CIDP may present localized radiculopathy in early phase and is important to point out various mode of onset among CIDP.

Somatosensory evoked potentials to median nerve stimulations were recorded in 21 patients with hypoxic coma within 24 hours from the onset. According to the neurologic prognosis, the patients were classified into 4 groups, such as I, complete recovery (5 patients), II, partial recovery (3 patients), III, vegetable state (8 patients), IV, brain death (5 patients). Measurements performed include central conduction time (N13-N20 interpeak latency) and amplitude ratio between N20 and P25. As N20 and P25 disappeared in 3 of 8 vegetable patients and all of brain death patients, disappearance of these waves indicates poor neurologic prognosis. Central conduction time showed no significant difference. Amplitude ratio between N20 and P25 (P25/N20) revealed significant decrease in vegetative patients for normal control subjects, complete recovery and partial recovery patients (p less than 0.05). Measurement of this ratio in early phase is useful to predict neurologic outcome in patients with hypoxic coma.