Ramsay Hunt syndrome associated with solitary nucleus, spinal trigeminal nucleus and tract, and vestibular nucleus involvement on sequential magnetic resonance imaging.

Ramsay Hunt syndrome (RHS) is an acute peripheral facial nerve paralysis typically accompanied by erythematous vesicular lesions of the auricular skin. The etiology is considered to be geniculate ganglionitis due to reactivation of varicella-zoster virus (VZV). Encephalitis is a rare but serious complication of VZV reactivation. Clarifying the regional and temporal evolution of the lesions on magnetic resonance imaging (MRI) would help with understanding the pathology of the lesion, but this information is lacking in encephalitis with RHS. Therefore, here, we reviewed sequential MR images in three RHS cases complicated by brainstem lesions. All the regions of the lesions represent specific neuronal structures-the ipsilateral solitary nucleus (SN) and spinal trigeminal nucleus and tract (STNT) in case 1; bilateral SN, ipsilateral STNT, and vestibular nucleus in case 2; ipsilateral SN and vestibular nucleus in case 3-and this seems to account for the persistent robust symptoms. Case 1 initially showed no abnormalities on MRI and cases 2 and 3 showed weak signals on the first MRI which subsequently plateaued. These observations suggest the timeframe within which it becomes possible to detect regional and temporal evolution, namely, that the distribution of the affected regions expands between weeks 2 and 5 after onset of facial paralysis. These observations and the findings of a literature review indicate that the SN, STNT, and vestibular nucleus are relatively prone to developing encephalitis after RHS.

Posterior Interosseous Neuropathy with Peripheral Dystonia: A Case Report.

Background: Posterior interosseous neuropathy is an uncommon cause of peripheral dystonia. Case Report: A 62-year-old man awakened and noticed right finger drop. A neurological examination revealed posterior interosseous neuropathy with dystonia-like finger movements. Abnormal movements were predominantly observed in the right thumb, ring finger, and little finger. Within 2 weeks, the muscle weakness in the right fingers had completely improved. However, a brief abnormal posture of the right thumb was persistent. Discussion: The residual abnormal posture of the right thumb may reflect pre-existing motor control abnormalities, which may have contributed to the onset of posterior interosseous neuropathy-associated peripheral dystonia.

Hand-foot synkinesis in a patient with phenytoin intoxication.

Here we report the first case of phenytoin intoxication that was closely associated with hand-foot synkinesis. This case suggests a close association between cerebellar dysfunction and hand-foot synkinesis. In patients with hand-foot synkinesis, lesions of not only the secondary motor areas but also the cerebellum should be considered.

Occipital Neuralgia Secondary to C2 Spinal Cord Infarction.

We herein report the first case of occipital neuralgia secondary to spinal cord infarction. A 74-year-old woman suddenly developed numbness and dysmetria in her right arm. Two days later, she developed a paroxysmal shooting pain in the right posterior part of the scalp three to five times per day. Magnetic resonance imaging revealed a hyperintense lesion in the right posterior column and dorsal root entry zone at the C2 level. The patient was subsequently diagnosed with occipital neuralgia secondary to spinal cord infarction. Diverse etiologies need to be considered in occipital neuralgia secondary to spinal cord lesions.

Bilateral Vocal Cord Paralysis Associated with Meningeal Carcinomatosis from Lung Adenocarcinoma.

Cranial neuropathy is a clinical manifestation of meningeal carcinomatosis (MC); however, the glossopharyngeal and vagus nerves are rarely impaired. Therefore, dysphagia and bilateral vocal cord paralysis (BVCP) are extremely rare manifestations of MC. Here, we present a case of MC from a lung adenocarcinoma presenting with dysphagia and BVCP. An 84-year-old man with a 4-year history of left lung adenocarcinoma developed dysphagia and hoarseness. Flexible nasopharyngoscopy revealed BVCP. Ten days later, the patient developed stridor and respiratory distress. A tracheotomy was performed to prevent airway obstruction. Gadolinium-enhanced magnetic resonance imaging (MRI) of the brain showed enhancement of the bilateral glossopharyngeal and vagus nerves, and several enhancing lesions in the right internal auditory canal, left cerebellum, fourth ventricle, pons, cerebral aqueduct, and right frontal lobe, suggesting MC and brain metastasis. Based on the clinical history of malignancy and the MRI findings, the patient was diagnosed with MC. As the patient refused additional treatment, including chemotherapy and radiation, only palliative care was provided. To the best of our knowledge, this was the first case of MC from a solid tumor presenting with BVCP. When patients with malignancy present with BVCP, MC should be considered.

A case of chronic inflammatory demyelinating polyneuropathy following COVID-19 vaccine.

We report a 44-year-old woman who presented with bilateral weakness of the hands and distal paresthesia of the arms on the next day of the second COVID-19 vaccine, and gradually progressed ascending weakness of the arms and legs, and sensory ataxia beyond 2 months. She was diagnosed as a chronic inflammatory demyelinating polyneuropathy (CIDP) following COVID-19 vaccine on the basis of clinical and electrophysiological findings. This is a first case diagnosed as a CIDP following COVID-19 vaccine alone.

Lambert-Eaton Myasthenic Syndrome Caused by Atezolizumab in a Patient with Small-cell Lung Cancer.

We herein report a 74-year-old man who developed Lambert-Eaton myasthenic syndrome (LEMS) during atezolizumab treatment for extensive-stage small-cell lung cancer. He was started on maintenance immunotherapy with atezolizumab every three weeks after four cycles of atezolizumab plus carboplatin plus etoposide combination therapy. After 13 cycles of maintenance atezolizumab therapy, he complained of muscular weakness and fatigue. Findings from a nerve conduction study and positive findings for anti-P/Q-type voltage-gated calcium channel antibody resulted in a diagnosis of LEMS. This was a rare case of LEMS as a neurological immune-related adverse event induced by atezolizumab therapy.

Index finger pointing posture in a patient with drug-induced foot tremor.

A 41-year-old woman who had been taking paroxetine began taking tramadol for bilateral ankle pain. A few days later, the patient presented acutely with both feet tremors. During a mental arithmetic task, index-finger pointing posture briefly appeared on the left side. Co-administration of paroxetine and tramadol increases the risk of serotonin toxicity. This is the first reported case of index-finger pointing posture which was associated with serotonin toxicity.

Apraxia of eyelid opening after subthalamic deep brain stimulation may be caused by reduction of levodopa.

Apraxia of eyelid opening (ALO) is an infrequent side effect of deep brain stimulation (DBS) of the subthalamic nucleus (STN) for Parkinson's disease (PD). However, the pathogenesis of ALO after STN DBS is not well understood. We report on two patients who suffered from disabling ALO after bilateral STN DBS. Their ALO improved by resuming the levodopa medication that had been discontinued after the surgery. Although ALO after STN DBS is considered as an adverse effect of STN stimulation, postoperative modification of dopaminergic medication may be a cause of ALO after STN DBS.

Miller Fisher Syndrome Mimicking Tolosa-Hunt Syndrome.

We herein report a patient with Miller Fisher syndrome mimicking Tolosa-Hunt syndrome. A 47-year-old man presented with right orbital pain and diplopia. On a neurological examination, he had right oculomotor nerve palsy and diminished deep tendon reflexes. Brain magnetic resonance imaging failed to show any parenchymal lesions; however, the bilateral oculomotor nerves were gadolinium-enhanced. The presence of a triad of orbital pain, ipsilateral oculomotor nerve palsy, and a rapid response to steroid therapy met the diagnostic criteria for Tolosa-Hunt syndrome. After discharge, antibodies against GQ1b and GT1a were reported to be positive only with phosphatidic acid. The present case was ultimately diagnosed as an incomplete phenotype of Miller Fisher syndrome.

Early treatment for IgG4-related disease may prevent cognitive impairment caused by cerebral vasculitis: A case report and review of the literature.

IgG4-related disease (IgG4-RD) is a recently recognized disease entity. A 74-year-old male presented with transient headache. He was diagnosed IgG4-RD by pancreatic biopsy at the age of 72. Magnetic Resonance Imaging (MRI) showed disseminated cerebral microbleeds and microinfarctions in time and space. It suggested cerebral vasculitis, however any causative factor were not confirmed. IgG4-RD rarely causes cerebral vasculitis. This might be a first case of an asymptomatic cerebral vasculitis due to IgG4-RD. Patient was started on oral prednisolone, and no neurological or neuropsychological symptom was clinically observed. The MRI findings improved after treatment, and revealed no indication of newly lesions at 6-months follow-up. Early treatment for IgG4-RD may be recommended to prevent irreversible cognitive dysfunction.

Octanoic acid promotes branched-chain amino acid catabolisms via the inhibition of hepatic branched-chain alpha-keto acid dehydrogenase kinase in rats.

OBJECTIVE: It has been reported that administration of octanoic acid, one of medium-chain fatty acids (MCFAs), promoted leucine oxidation in vitro and in vivo, but it remained unclear how octanoic acid stimulated leucine oxidation. Therefore, the aim of this study was to elucidate the mechanism that octanoic acid facilitates branched-chain amino acid (BCAA) catabolism. MATERIALS/METHODS: In in vivo experiments, male rats were orally administered MCFAs as free fatty acids or triacylglycerol (trioctanoin), and then activities of hepatic branched-chain α-ketoacid dehydrogenase (BCKDH) complex (BCKDC) and BCKDH kinase (BDK) and alterations in the concentration of blood components were analyzed. In in vitro experiments, purified BCKDC associated with BDK (BCKDH-BDK complex) was reacted with various concentrations of hexanoic, octanoic, and decanoic acids. RESULTS: Oral administration of trioctanoin in rats activated hepatic BCKDC via down-regulation of BDK activity in association with a decrease in plasma BCAA concentration and an increase in serum ketone body concentration. In vitro experiments using purified BCKDH-BDK complex showed that MCFAs (hexanoic, octanoic, and decanoic acids) inhibited BDK activity and that this inhibition was higher in hexanoic and octanoic acids than in decanoic acid. Oral administration of octanoic acid, but not decanoic acid, in rats activated hepatic BCKDC via down-regulation of BDK activity by decreasing the amount of BDK bound to the complex. The serum ketone body level was elevated by both administration of octanoic acid and decanoic acid. CONCLUSION: These results suggest that octanoic acid promotes BCAA catabolism in vivo by activation of BCKDC via decreasing the bound form of BDK.

[An autopsy case of purulent meningitis, presenting high signals in subarachnoid space and ventricles in diffusion weighted images (DWIs)].

A 79-year-old, bedridden woman with an untreated colon cancer, developed abrupt disturbance of consciousness and high fever. Brain MRI showed significant high signals in the subarachnoid space and ventricles in diffusion-weighted images (DWIs), and she died on the same day. At autopsy, much exudate was found over the base of the brain, leading to a diagnosis of purulent meningitis. On histological findings, inflammatory cell infiltration was significantly restricted within the subarachnoid space, but not into the brain parenchyma. This case report demonstrated that high signals in subarachnoid space and ventricles in DWIs may be very useful for diagnosis of purulent meningitis.

Regulation of hepatic branched-chain α-ketoacid dehydrogenase complex in rats fed a high-fat diet.

Branched-chain α-ketoacid (BCKA) dehydrogenase complex (BCKDC) regulates branched-chain amino acid (BCAA) metabolism at the level of BCKA catabolism. It has been demonstrated that the activity of hepatic BCKDC is markedly decreased in type 2 diabetic animal models. In this study, we examined the regulation of hepatic BCKDC in rats with diet-induced obesity (DIO). Rats were fed a control or a 60% of energy high-fat diet (HFD) for twelve weeks. Concentrations of blood components and the activities and protein amounts of hepatic BCKDC and its specific kinase (BDK) were measured. The concentrations of plasma glucose, insulin, and corticosterone were significantly elevated in DIO rats compared to those fed the control diet, suggestive of insulin resistance. Blood BCAA concentrations were not increased. The activity of hepatic BCKDC that was present in the active form in the liver was higher in DIO rats compared to controls, although the total activity and the enzyme amount were not different between two diet groups. The activity of hepatic BDK and the abundance of BDK bound to the BCKDC were decreased in DIO rats. The total amount of hepatic BDK was also significantly decreased in DIO rats. In rats made obese through HFD feeding, in contrast to prior studies in rat models of type 2 diabetes, hepatic BDK was down-regulated and thereby hepatic BCKDC was activated, suggesting that DIO promotes liver BCKA catabolism. In this model there was no evidence that increased blood BCAAs drive DIO-associated insulin resistance, since concentrations of BCAAs were not altered by DIO.

Phosphorylation of collapsin response mediator protein-2 regulates its localization and association with hippocampal cholinergic neurostimulating peptide precursor in the hippocampus.

Hippocampal cholinergic neurostimulating peptide (HCNP) induces the synthesis of acetylcholine in the medial septal nucleus in vitro and in vivo. The precursor, HCNP-pp, is a multifunctional protein participating in important signaling pathways, such as MAPK/ERK kinase (MEK) and G-protein-coupled receptor kinase 2 (GRK2). We recently demonstrated that HCNP-pp colocalizes with collapsin response mediator protein-2 (CRMP-2) at presynaptic terminals in the hippocampus, suggesting that HCNP-pp may play an important role in presynaptic function in association with CRMP-2. To clarify the involvement of phosphorylation in regulating the interaction between HCNP-pp and CRMP-2, we investigated the colocalization of HCNP-pp with unphosphorylated- and/or phosphorylated-CRMP-2 (pCRMP-2) at presynaptic terminals. We further determined if the phosphorylation of CRMP-2 affects the binding between those proteins. Here, we demonstrate that HCNP-pp predominantly colocalizes and associates with unphosphorylated and/or pSer-522-CRMP-2 at presynaptic terminals in the hippocampus. Interestingly, HCNP-pp does not associate with pThr-509/514-CRMP-2, which is primarily localized at postsynaptic terminals. These findings suggest that HCNP-pp, in association with unphosphorylated and/or pSer522-CRMP-2, plays an important role in presynaptic function in the mature hippocampus.

Suppression of astrocyte lineage in adult hippocampal progenitor cells expressing hippocampal cholinergic neurostimulating Peptide precursor in an in vivo ischemic model.

Hippocampal cholinergic neurostimulating peptide (HCNP) is known to promote differentiation of septohippocampal cholinergic neurons. The HCNP precursor protein (HCNP-pp) may play several roles, for example, as an ATP-binding protein, a Raf kinase inhibitor protein, and a phosphatidylethanolamine-binding protein, as well as a precursor for HCNP. This study therefore aimed to elucidate the involvement of HCNP-pp in specific neural lineages after stroke using a hypoxic-ischemic (HI) rat model of brain ischemia. The specific neural lineages in the hippocampus were investigated 14 days after ischemia. Some bromodeoxyuridine (BrdU)(+) neural progenitor cells in the hippocampus of hypoxic, HI, or sham-operated rats expressed HCNP-pp. Almost half of the BrdU(+)/HCNP-pp(+) cells also expressed the oligodendrocyte lineage marker 2',3'-cyclic nucleotide 3'-phosphodiesterase, whereas only a few BrdU(+)/HCNP-pp(+) cells in the hippocampus in HI brains expressed the neuronal lineage marker, doublecortin (DCX). Interestingly, no BrdU(+)/HCNP-pp(+) progenitor cells in hypoxic, HI, or sham-operated brains expressed the astrocyte lineage marker, glial fibrillary acidic protein. Together with previous in vitro data, the results of this study suggest that the expression level of HCNP-pp regulates the differentiation of neural progenitor cells into specific neural lineages in the HI hippocampus, indicating that neural stem cell fate can be controlled via the HCNP-pp mediating pathway.