MR Neurography and Quantitative Muscle MRI of Parsonage Turner Syndrome Involving the Long Thoracic Nerve.

BACKGROUND: Parsonage-Turner syndrome (PTS) is characterized by severe, acute upper extremity pain and subsequent paresis and most commonly involves the long thoracic nerve (LTN). While MR neurography (MRN) can detect LTN hourglass-like constrictions (HGCs), quantitative muscle MRI (qMRI) can quantify serratus anterior muscle (SAM) neurogenic changes. PURPOSE/HYPOTHESIS: 1) To characterize qMRI findings in LTN-involved PTS. 2) To investigate associations between qMRI and clinical assessments of HGCs/electromyography (EMG). STUDY TYPE: Prospective. POPULATION: 30 PTS subjects (25 M/5 F, mean/range age = 39/15-67 years) with LTN involvement who underwent bilateral chest wall qMRI and unilateral brachial plexus MRN. FIELD STRENGTH/SEQUENCES: 3.0 Tesla/multiecho spin-echo T2-mapping, diffusion-weighted echo-planar-imaging, multiecho gradient echo. ASSESSMENT: qMRI was performed to obtain T2, muscle diameter fat fraction (FF), and cross-sectional area of the SAM. Clinical reports of MRN and EMG were obtained; from MRN, the number of HGCs; from EMG, SAM measurements of motor unit recruitment levels, fibrillations, and positive sharp waves. qMRI/MRN were performed within 90 days of EMG. EMG was performed on average 185 days from symptom onset (all ≥2 weeks from symptom onset) and 5 days preceding MRI. STATISTICAL TESTS: Paired t-tests were used to compare qMRI measures in the affected SAM versus the contralateral, unaffected side (P < 0.05 deemed statistically significant). Kendall's tau was used to determine associations between qMRI against HGCs and EMG. RESULTS: Relative to the unaffected SAM, the affected SAM had increased T2 (50.42 ± 6.62 vs. 39.09 ± 4.23 msec) and FF (8.45 ± 9.69 vs. 4.03% ± 1.97%), and decreased muscle diameter (74.26 ± 21.54 vs. 88.73 ± 17.61 µm) and cross-sectional area (9.21 ± 3.75 vs. 16.77 ± 6.40 mm2 ). There were weak to negligible associations (tau = -0.229 to <0.001, P = 0.054-1.00) between individual qMRI biomarkers and clinical assessments of HGCs and EMG. DATA CONCLUSION: qMRI changes in the SAM were observed in subjects with PTS involving the LTN. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 1.

Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease and Transverse Myelitis Probably Associated With SARS-CoV-2 mRNA Vaccines: Two Case Reports.

Post-vaccination CNS demyelinating syndromes have been reported with a variety of vaccines including the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines. We report a case of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) probably associated with the mRNA-1273 (by Moderna) SARS-CoV-2 mRNA vaccine, and a case of acute transverse myelitis (ATM) probably associated with the BNT162b2 (by Pfizer-BioNTech) SARS-CoV-2 mRNA vaccine. A 38-year-old man developed left blurry vision, lower extremity weakness/paresthesia, and bowel/bladder dysfunction three days after receiving the Moderna vaccine. He was diagnosed with left optic neuritis and longitudinally extensive transverse myelitis; he tested positive for the myelin oligodendrocyte glycoprotein antibody. A 39-year-old woman presented with progressive lower extremity weakness/numbness 7 days after receiving the Pfizer vaccine. She was diagnosed with ATM. Both patients improved with intravenous corticosteroids. The association between CNS demyelinating syndromes and vaccination has been reported for many years. We describe two cases of acute CNS demyelinating events probably associated with both mRNA variations of the SARS-CoV-2 vaccines. While the risk of CNS demyelinating events is non-negligible, the incidence is very low and the overall benefits of vaccination outweigh the marginal risk. However, providers should be aware of this potential neurological complication of the SARS-CoV-2 mRNA vaccines.

Cerebellar Ischemia Presenting as Transient Global Amnesia.

Transient global amnesia (TGA) consists of acute-onset anterograde amnesia and typically resolves within 24 hours. Reported etiologies of TGA include transient ischemia to the hippocampus or thalamus, migraine, venous flow abnormalities, and epilepsy. There are no reports of cerebellar ischemia as an etiology of TGA. A 78-year-old woman with a medical history of diabetes presented to the Ohio State University ER after a period of anterograde amnesia lasting 3 hours. She was alert during the event, but asked the same questions repeatedly. Upon arrival to the ER, she was hypertensive but clinically back to baseline, with no recall of the 3-hour time period. An MRI of her brain revealed an isolated hyperintense signal on diffusion-weighted imaging (DWI) at the junction of the superior cerebellum and vermis, with apparent diffusion coefficient correlation. Vascular imaging of the brain and neck and a routine EEG were unremarkable. We diagnosed her with cerebellar ischemia presenting as TGA. She had no head injury, migraine, or history of epilepsy to suggest alternative etiologies of TGA. An increasing amount of literature has reported that the cerebellum is linked to the limbic system. A case series of SPECT imaging on individuals with TGA revealed transient cerebellar vermis hypoperfusion in addition to hippocampal DWI changes. We present what may be a novel report of isolated cerebellar ischemia presenting as TGA, and we add to the literature for clinicians to consider the possibility that damage to the cerebellum or its circuit to the cerebrum or thalamus can present as TGA.

Recurrent Miller Fisher: A Case Report Along With a Literature and an EMG/NCS Review.

MFS has been reported to recur in 10-12% of patients. There may be a genetic component related to HLA-DR2. Anti-GAD antibodies can be present in MFS along with anti-GQ1b. Common EMG/NCS associations consist of a predominantly axonal, sensory polyneuropathy and absent H reflexes. A 32-year-old female with a history of hypothyroidism presented to our institution twice with symptoms of diplopia, lower extremity weakness and distal paresthesias occurring a year apart. She had ophthalmoplegia, reduced reflexes, and ataxia on exam. CSF showed a borderline elevated protein of 47 and white blood cells <3. She was positive for anti-GQ1b both times. Her anti-GAD65 antibody was elevated during both admissions. EMG/NCS on her first admission revealed comparatively reduced sensory nerve action potentials (SNAPs) and a normal blink reflex. Her SNAPs improved on the second admission, however, the EMG was performed only 2 days after the onset of her symptoms, limiting some early findings that may have not matured electrophysiologically. She was treated with IVIG on both occasions with rapid recovery within 5 days. This case highlights the fact that MFS can be recurrent. It also provides further evidence that anti-GAD antibodies may be associated with MFS. Reported findings of the blink reflex in MFS are diverse and further data is needed to determine if certain findings are more predominant than others. Treatment typically consists of IVIG, though steroids may also be considered for recurrence. Prognosis is generally favorable, regardless of treatment.

Acute Thrombocytopenia After Tissue Plasminogen Activator for Stroke.

We present what may be the first case report of acute thrombocytopenia after tissue plasminogen activator (tPA) in the setting of stroke. Early fibrinogen degradation coagulopathy (EFDC) after tPA has been described in the past and acute thrombocytopenia may fall into this spectrum. Further studies are needed to evaluate the bleeding and mortality risk associated with thrombocytopenia after tPA.

Charcot-Marie-Tooth: From Molecules to Therapy.

Charcot-Marie-Tooth (CMT) is the most prevalent category of inherited neuropathy. The most common inheritance pattern is autosomal dominant, though there also are X-linked and autosomal recessive subtypes. In addition to a variety of inheritance patterns, there are a myriad of genes associated with CMT, reflecting the heterogeneity of this disorder. Next generation sequencing (NGS) has expanded and simplified the diagnostic yield of genes/molecules underlying and/or associated with CMT, which is of paramount importance in providing a substrate for current and future targeted disease-modifying treatment options. Considerable research attention for disease-modifying therapy has been geared towards the most commonly encountered genetic mutations (PMP22, GJB1, MPZ, and MFN2). In this review, we highlight the clinical background, molecular understanding, and therapeutic investigations of these CMT subtypes, while also discussing therapeutic research pertinent to the remaining less common CMT subtypes.