Guillain-Barré Syndrome After COVID-19 Infection in Korea: A Case Series.

Guillain-Barré syndrome (GBS) is an autoimmune-driven condition characterized by acute polyneuropathy, often emerging as a sequel to prior infections or vaccinations. This study presents the first reported cases of GBS emerging after the full recovery from coronavirus disease 2019 (COVID-19) infection in Korea. Despite experiencing mild acute COVID-19 symptoms, these patients faced substantial weakness attributed to GBS, significantly affecting their daily lives. The timely administration of intravenous immunoglobulin treatment halted the progression of symptoms, underscoring the critical importance of early intervention. These cases highlight the potential for neurological complications associated with COVID-19 and underscore the necessity for continuous monitoring and timely medical care.

Clinical pitfalls and serological diagnostics of MuSK myasthenia gravis.

BACKGROUND: We aimed to evaluate the diagnostic accuracy of enzyme-linked immunosorbent assay (ELISA) for anti-muscle specific tyrosine kinase (MuSK) antibody (Ab) in a large cohort of anti-acetylcholine receptor (AChR) Ab-negative generalized myasthenia gravis (MG), and also to investigate clinical contexts for the diagnosis of MuSK MG. METHODS: A retrospective study of 160 patients with a clinical suspicion of AChR Ab-negative generalized MG was performed. The serum samples were tested for anti-clustered AChR Ab by cell-based assay (CBA), anti-MuSK Ab by ELISA, CBA and/or radioimmunoprecipitation assay (RIPA). Clinical data were compared between anti-MuSK Ab-positive MG and double seronegative (AChR and MuSK) MG groups. RESULTS: After excluding non-MG and clustered AChR Ab-positive patients, we identified 89 patients as a cohort of AChR Ab-negative generalized MG. Anti-MuSK Ab was positive by ELISA in 22 (24.7%) patients. While CBA identified five additional anti-MuSK Ab-positive patients, the results of ELISA were mostly consistent with CBA and RIPA with Cohen's kappa of 0.80 and 0.90, respectively (p < 0.001). The most frequent differential diagnosis was motor neuron disease particularly of bulbar onset which showed remarkably overlapping clinical and electrophysiological features with MuSK MG at presentation. CONCLUSION: While confirming the highest sensitivity of CBA for detecting anti-MuSK Ab, our results highlight the clinical pitfalls in making a diagnosis of MuSK MG and may support a diagnostic utility of MuSK-ELISA in clinical practice.

Cross-sectional area reference values for high-resolution ultrasonography of the lower extremity nerves in healthy Korean adults.

The cross-sectional area (CSA) reference values of the lower extremity nerves in Asians have been rarely reported. For this study, 107 sex- and age-matched, healthy subjects with a mean age of 46 years (range, 24-75 years) were recruited. All subjects underwent standardized nerve conduction studies of the upper and lower extremities. The CSA was measured unilaterally at 12 sites in the lower extremity nerves, including the femoral, lateral femoral cutaneous, sciatic, common peroneal, superficial peroneal, deep peroneal, tibial, and sural nerves. The CSA significantly correlated with height, weight, and body mass index. The CSA was significantly larger in males than females at most nerves except for the lateral femoral cutaneous, common peroneal (fibular head), and superficial peroneal nerves (distal calf). There was no statistically significant difference between the age groups except for the tibial nerve (ankle). The results of this study provide CSA reference values for the lower extremity nerves including small branches and the values can be useful in the ultrasonographic investigation of various peripheral neuropathies in East Asian populations.

Posterior Interosseous Fascicular Constriction Within the Radial Nerve in a Diabetic Patient With Bilateral Neuralgic Amyotrophy: A Case Report.

Background: Neuralgic amyotrophy (NA) is an acute, monophasic, painful inflammatory dysimmune focal, or multifocal mononeuropathy. The lesion in NA is not always restricted to the brachial plexus but also involves individual nerves or branches. The prognosis of NA is less favorable than previously assumed, but the reasons for poor recovery remain unknown. Nerve constriction may be one of the causes of poor prognosis in NA. Case Presentation: Herein, we described a 54-year-old male with a history of type 2 diabetes in whom bilateral neuralgic amyotrophy developed with constriction of the posterior interosseous fascicle within the radial nerve. The patient experienced sudden-onset severe pain in both shoulders followed, 2 days later, by weakness in bilateral shoulders and the left forearm extensors over the subsequent month. The left forearm extensors were more severely affected than both shoulder girdle muscles. He noted a 7-kg weight loss for 1 month before pain onset. After diagnosing diabetic NA based on the clinical symptoms, imaging, and electrophysiological studies, treatment with systemic steroids improved pain and weakness in both shoulder muscles. Weakness in the left forearm extensors persisted after 1 month of steroid treatment. Follow-up ultrasound revealed constriction of the posterior interosseous fascicle within the main trunk of the left radial nerve at the elbow. Surgical exploration at 6 months after onset identified fascicle constriction, for which neurolysis was performed. Weakness in the extensors of the wrist and fingers did not improve during the 16-month follow-up. Conclusion: A single constriction of the fascicle within a peripheral nerve may often be under-recognized if NA presents with variable degrees of weakness in bilateral upper limbs. Furthermore, fascicular constriction without edema of the parent nerve may be easily missed on the initial ultrasound. A lack of early recognition of nerve constriction and delay in surgical intervention can result in unfavorable outcomes. The physician should consider the possibility of the fascicular constriction when evaluating patients suspected of brachial NA with significant weakness in the distal upper limb compared to the proximal weakness or weakness of the distal upper limb that does not improve over time.

Recurrent Transient Neurological Deficit Due to Intracerebral Steal Phenomenon in Association with a Developmental Venous Anomaly.

We report a symptomatic developmental venous anomaly (DVA) not causing parenchymal abnormality to provide a pathophysiologic clue in patients with recurrent transient neurologic deficit. A 32-year-old male presented with recurrent transient motor aphasia and headache in the left fronto-temporal region for three years. The symptoms usually lasted for one hour. Brain computed tomography (CT) angiography and magnetic resonance imaging using gradient recalled echo showed a prominent penetrating vein at the left frontal periventricular region. Brain CT perfusion imaging performed during the symptoms revealed increased perfusion in the corresponding area with relatively decreased perfusion in the left fronto-temporal cortices. Digital subtraction angiography revealed collecting venous blood from the left septal and thalamostriate veins draining into the left cavernous sinus without early arteriovenous shunting. In this patient, an inciting incident might have led to imbalance of the venous flow surrounding the DVA, causing venous hypertension and the intracerebral steal phenomenon in the surrounding area. The relatively hypoperfused cortical area adjacent to the DVA could be considered the cause of the transient motor aphasia, while venous hypertension could be the cause of the headache.

Cross-sectional area reference values for high-resolution ultrasonography of the upper extremity nerves in healthy Asian adults.

ABSTRACT: In this study, multiple-site, cross-sectional area (CSA) reference values were established for major peripheral nerves, including small branches, in the upper extremity of a healthy Asian population.This study included 107 prospectively recruited age-matched, healthy subjects with a mean age of 46 years (range, 24-75 years). All subjects underwent standardized nerve conduction studies for the median, ulnar, peroneal, posterior tibial, and sural nerves. CSA was measured unilaterally at 21 sites of the median, ulnar, radial, posterior interosseous, superficial radial sensory, musculocutaneous, lateral antebrachial cutaneous, and medial antebrachial cutaneous nerves.According to their age, the subjects were assigned to the younger group (20-40 years, n = 40), the middle group (40-59 years, n = 40), and the older group (60-80 years, n = 27). The significant differences of CSA values between age groups were found only at certain sites, such as the median (wrist, P = .003), ulnar (medial epicondyle, P = .031; forearm, P = .022), radial (antecubital fossa, P = .037), and superficial radial sensory nerve (P = .028). The CSA significantly correlated with gender, height, weight, and body mass index.This study provides CSA reference values for nerves, including small sensory nerves in the upper extremity, which can be useful in the ultrasonographic investigation of various peripheral neuropathies in the upper extremity.

Paramagnetic Rims in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder: A Quantitative Susceptibility Mapping Study with 3-T MRI.

BACKGROUND AND PURPOSE: Iron retained by activated microglia and macrophages in multiple sclerosis (MS) lesions may serve as a marker of innate immune system activation. Among several magnetic resonance imaging (MRI) methods, there has been recent interest in using quantitative susceptibility mapping (QSM) as a potential tool for assessing iron levels in the human brain. This study examined QSM findings in MS and neuromyelitis optica spectrum disorder (NMOSD) lesions obtained with 3-T MRI to assess imaging characteristics related to paramagnetic rims around brain lesions in MS and NMOSD. METHODS: This study included 32 MS and 21 seropositive NMOSD patients. MRI images were obtained using two 3-T MRI devices (Ingenia, Philips Healthcare; and Magnetom Verio, Siemens Healthineers) during routine diagnosis and treatment procedures. Multi and single echo gradient echo magnitude and phase images were obtained for QSM reconstruction. QSM images were used to characterize the detected lesions, and the findings were compared between MS and NMOSD. RESULTS: Totals of 71 and 35 MRI scans were performed during the study period in MS and NMOSD patients, respectively. In QSM images, paramagnetic rims were found in 26 (81.2%) MS patients and 1 (4.8%) NMOSD patient. Eight of the 22 MS patients and only 1 of the 10 NMOSD patients who underwent follow-up MRI showed new paramagnetic rims. The paramagnetic rim lesions appeared after enhancement or in new T2-weighted lesions without enhancement. CONCLUSIONS: Paramagnetic rims might be a characteristic MRI finding for MS, and therefore they have potential as an imaging marker for differentially diagnosing MS from NMOSD using 3-T MRI.

Anti-aquaporin-4 Antibody Positive Optic Neuritis Following Scrub Typhus in an Elderly Female.

INTRODUCTION: Aquaporin-4 antibody (AQP4-Ab) is specific for neuromyelitis optica spectrum disorder (NMOSD) and so is helpful to distinguish NMOSD from other autoimmune diseases. Several viral infections may play a role in the onset of NMOSD. CASE REPORT: We describe a case of a previous healthy 82-year-old woman who presented with acute visual loss occurring 3 weeks after scrub typhus. Physical examination showed a relatively afferent pupillary defect in the right eye and ophthalmoscopy revealed edema of the right optic disc. Enhanced magnetic resonance imaging revealed enhancement of the right optic nerve. Serological testing showed AQP4-Ab. After methylprednisolone pulse therapy followed by oral tapering of prednisolone, visual dysfunction was improved. Subsequently she experienced no attacks for 5 years. CONCLUSIONS: Optic neuritis (ON) associated with scrub typhus is extremely rare. Our case support that scrub typhus could trigger ON in a lifelong asymptomatic patient with AQP4-Ab and AQP4-Ab should be considered in a very old age patient with suspected postinfectious inflammatory ON.

Association of arterial stiffness with cognition in patients with Lewy body disorder.

The brachial-ankle pulse wave velocity (baPWV) is a marker for arterial stiffness, which is associated with cardiovascular diseases. Arterial stiffness is associated with cognitive function in the elderly and patients with Alzheimer's disease (AD). We aimed to investigate the association between arterial stiffness and cognitive function in patients with Lewy body disorder (LBD), including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). We consecutively included 123 patients with PD, 10 patients with DLB, and 27 AD controls. Patients with PD were divided into three groups of normal cognition (PD-NC, n = 63), mild cognitive impairment (PD-MCI, n = 43), and dementia (PD-D, n = 17). Arterial stiffness, measured as baPWV, was compared between the PD-NC, PD-MCI, PD-D, DLB, and AD patients. In LBD, we analyzed the association between arterial stiffness and each cognitive domain with adjustment for covariates. Higher baPWV was significantly associated with cognitive decline in patients with LBD (baPWV in PD-D > PD-MCI > PD-NC; DLB > PD-NC). There was no significant difference in baPWV between PD-D, DLB, and AD patients. In LBD patients, higher baPWV was associated with lower mini mental state examination score (ß ± SE = -0.003 ± 0.001, p = 0.007) and more severe dementia. Higher baPWV was also associated with lower performance in attention, language, visuospatial function, memory, and executive function in LBD patients. This suggests that vascular brain injury is associated with cognitive dysfunction in LBD.

Clinical Characteristics of Parkinson's Disease Developed from Essential Tremor.

BACKGROUND: Recent genetic and epidemiological studies have shown that there is a link between essential tremor and Parkinson's disease (PD). However, there is a lack of data about the clinical features of PD developed from essential tremor. OBJECTIVE: To explore and describe the clinical characteristics of Parkinson's disease developed from essential tremor (ET-PD). METHODS: Twenty-five ET-PD patients and 124 IPD controls were enrolled according to each criterion. Motor and non-motor features and dopamine transporter uptake were compared between the two groups. RESULTS: Rest and action tremors were more severe in ET-PD patients than in IPD patients. In addition, tremor disorder of first-degree relatives occurred more frequently in the ET-PD group than in the IPD group. A comparison between cases with ET-PD and IPD was not significant for striatal dopamine transporter uptake. Among the non-motor features, sleep disorder frequency, especially rapid-eye-movement sleep behavioral disorder, were lower in patients with ET-PD than in those with IPD, and smell identification test scores were higher in patients with ET-PD than in those with IPD. The prevalence of other non-motor symptoms did not differ between the two groups. CONCLUSION: This is the first comparison of motor and non-motor features between ET-PD and IPD. ET-PD and IPD have different characteristic motor and non-motor features from the nosologic perspective.

Arterial Stiffness and Cardiovascular Autonomic Dysfunction in Patients with Parkinson's Disease.

BACKGROUND: Pulse wave velocity is a marker of arterial stiffness and a surrogate marker of vascular damage. Autonomic abnormalities associated with blood pressure are relatively commonly observed in patients with Parkinson's disease (PD). OBJECTIVE: The purpose of this study was to compare arterial stiffness between patients with PD and controls and investigate the associations between cardiovascular autonomic dysfunction and pulse wave velocity in PD. METHODS: One hundred twenty-five PD patients without diabetes mellitus were enrolled into this study, along with 22 age-matched controls. Orthostatic vital signs and ambulatory 24-hour blood pressure monitoring values were recorded. Pulse wave velocity was used to evaluate arterial stiffness. RESULTS: In PD, greater arterial stiffness was associated with orthostatic hypotension, supine hypertension, nocturnal hypertension, and nondipping. Dopaminergic treatment did not influence cardiovascular autonomic dysfunction or arterial stiffness. Although pulse wave velocity was mildly increased in patients with PD compared to controls, the arterial stiffness in PD patients without autonomic failure was similar to that in normal controls. Stiffer arteries were found only in patients with PD and autonomic failure. CONCLUSION: These findings suggest that cardiovascular autonomic dysfunction is associated with arterial stiffness in PD. PD itself does not affect arterial stiffness, whereas autonomic blood pressure disturbances influence alterations in arterial stiffness and architectural changes in the arteries of PD patients.