Neurological Complications of COVID-19 Infection: A Comprehensive Review.

The COVID-19 pandemic is well on its way to reaching endemic status across the globe. While the medical community's understanding of the respiratory complications induced by COVID-19 is improving, there is still much to be learned about the neurological manifestations associated with COVID-19 infection. This review aimed to compile relevant, available evidence of COVID-19-induced neurological complications and to provide information for each complication regarding symptomology, progression patterns, demographic risk factors, treatment, and causative mechanism of action when available. Data for this review was collected using a confined search on PubMed using the keywords ["COVID-19" OR "SARS-CoV-2"] AND ["neurological complications" OR "olfactory symptoms" OR "gustatory symptoms" OR "myalgia" OR "headache" OR "dizziness" OR "stroke" OR "seizures" OR "meningoencephalitis" OR "cerebellar ataxia" OR "acute myelitis" OR "Guillain Barré Syndrome" OR "Miller Fisher Syndrome" OR "Posterior Reversible Encephalopathy Syndrome"] between 2019 and 2023. A wide range of neurological manifestations impact a significant percentage of COVID-19 patients, and a deeper understanding of these manifestations is necessary to ensure adequate management. The most common neurological complications identified consist of olfactory and gustatory dysfunctions, myalgia, headache, and dizziness, while the most severe complications include stroke, seizures, meningoencephalitis, Guillain-Barré syndrome, Miller Fisher syndrome, acute myelitis, and posterior reversible encephalopathy syndrome. While this review effectively provides a roadmap of the neurological risks posed to COVID-19 patients, further research is needed to clarify the precise incidence of these complications and to elucidate the mechanisms responsible for their manifestation.

Phenotypic Spectrum and Natural History of Gillespie Syndrome. An Updated Literature Review with 2 New Cases.

BACKGROUND: Gillespie syndrome is a rare disorder caused by pathogenic variants in ITPR1 gene and characterized by the typical association of cerebellar ataxia, bilateral aniridia and intellectual disability. Since its first description in 1965, less than 100 patients have been reported and only 30 with a molecular confirmation. METHODS: We present two additional cases, both carrying a loss-of-function variant in the Gly2539 amino acid residue. We describe the clinical evolution of the patients, one of whom is now 17 years old, and discuss the updated phenotypic spectrum of the disorder. RESULTS: The study gives an overview on the condition, allowing to confirm important data, such as an overall positive evolution of development (with some patient not presenting intellectual disability), a clinical stability of the neurological signs (regardless of a possible progression of cerebellar atrophy) and ocular aspects, and a low prevalence of general health comorbidities. DISCUSSION: Data about development and the observation of middle-aged patients lend support to the view that Gillespie is to be considered a non-progressive cerebellar ataxia, making this concept a key point for both clinicians and therapists, and for the families.

Early-onset palatal myoclonus in Wernekinck commissure syndrome secondary to caudal paramedian midbrain infarction: A case report and a mini review of the literature.

INTRODUCTION: Wernekinck commissure syndrome (WCS) is an extremely rare midbrain syndrome, which selectively destroys the decussation of the superior cerebellar peduncle and the central tegmental tract, which commonly presents with bilateral cerebellar ataxia, dysarthria, and internuclear ophthalmoplegia. Palatal myoclonus in Wernekinck commissure syndrome is uncommon and often occurs as a late phenomenon due to hypertrophic degeneration of bilateral inferior olivary nuclei. MATERIAL AND METHOD: A patient with WCS, admitted to our hospital from December 2023, was chosen for this study, and the syndrome's clinical manifestations, imaging features, and etiology were retrospectively analyzed based on the literature. A 68-year-old right-handed East Asian man presented with dizziness, slurred speech, difficulty with swallowing and walking, and rhythmic contractions of the soft palate. He had several risk factors for ischemic cerebrovascular diseases (age, sex, dyslipidemia, hypertension and smoking history). Brain magnetic resonance imaging showed hyperintensity of DWI and hypointensity of ADC at the caudal midbrain which was around the paramedian mesencephalic tegmentum anterior to the aqueduct of midbrain. RESULTS: He was diagnosed with Wernekinck commissure syndrome (WCS) secondary to caudal paramedian midbrain infarction. He was started on dual antiplatelet therapy (aspirin and clopidogrel) and intensive statin therapy. Blood pressure and glucose were also adjusted. His symptoms improved rapidly, and he walked steadily and speak clearly after 7 days of treatment. CONCLUSIONS: Palatal myoclonus is known to occur as a late phenomenon due to hypertrophic degeneration of bilateral inferior olivary nuclei. However, Our case suggests that palatal myoclonus can occur in the early stages in WCS.

Neurologic Deficits Following Oral Misuse of the Nasal Decongestant Propylhexedrine.

INTRODUCTION: Propylhexedrine is an over-the-counter nasal decongestant used recreationally for amphetamine-like effects. Prior reports have associated intravenous misuse with brainstem dysfunction and diplopia. This is a case of propylhexedrine ingestion resulting in neurological impairment with associated MRI findings. CASE REPORT: A 21-year-old man presented with neurologic symptoms after ingesting propylhexedrine extracted from a 250 mg nasal inhaler into a lemon juice solution following recommendations from an online forum. He also followed recommendations to simultaneously ingest 1 g L-arginine to theoretically mitigate the risk of vasoconstriction. He developed flushing and euphoria before falling asleep. He awoke 12 h later with dizziness, intractable vomiting, diplopia, ataxia, dysmetria, and spontaneous horizontal nystagmus. Magnetic resonance imaging (MRI) revealed T2 enhancement concerning for vasogenic edema of the right posterior limbs of the internal capsule extending into the midbrain, cerebellar peduncles, and cerebellar white matter. Workup for primary vascular or autoimmune etiologies was unrevealing. Expanded drug testing was positive for mitragynine and THC. Blood analyzed via liquid chromatography quadrupole time-of-flight mass spectrometry was positive for propylhexedrine. On hospital day 6, the patient was discharged to physical rehabilitation with unresolved dysmetria and ataxia. DISCUSSION: Recreational oral misuse of propylhexedrine may be associated with neurologic injury. MRI findings in this case demonstrated vasogenic edema suggesting vasospasm as a possible etiology. Serum testing confirmed the presence of propylhexedrine. Although testing was also positive for mitragynine and THC, these have not been associated with similar neurologic deficits or MRI findings.

Acute Cerebellar Manifestations without Limbic Involvement in GABAB Receptor Autoimmune Encephalitis: Case Report and Literature Review.

Autoimmune encephalitis is a rapidly progressive inflammatory brain disease. Gamma-aminobutyric acid type B (GABAB) receptor autoimmune encephalitis is a rare subtype characterized by distinct clinical features. Diagnosis can be especially challenging when typical limbic symptoms and neuroimaging findings are absent. This case report underscores the importance of identifying this condition and starting immunosuppressive treatment promptly. A 59-year-old man presented with gait disturbances, dysarthria, and severe ataxia without cognitive impairment. Initial examinations, including a brain MRI, were unremarkable, except for an elevated cell count and protein in the cerebrospinal fluid. Despite receiving initial empirical antiviral treatment, his symptoms worsened, prompting the administration of intravenous methylprednisolone and immunoglobulin. After these immunosuppressive therapies, the cerebellar symptoms showed gradual improvement. Subsequent testing for antibodies to the GABAB receptor was positive in both the serum and cerebrospinal fluid. Follow-up MRI revealed cerebellar atrophy, consistent with a diagnosis of GABAB receptor-associated acute cerebellitis. This case illustrates that cerebellar symptoms can occur in the absence of more common limbic manifestations in GABAB receptor autoimmune encephalitis. The progression of cerebellar atrophy following an initially normal MRI is a significant finding that offers supporting evidence for the diagnosis of cerebellitis. A review of the literature identified similar cases of acute cerebellitis without limbic symptoms, although neuroimaging abnormalities in the cerebellum were not reported. Our case underscores the importance of increased clinical awareness and consideration of autoimmune causes, even when neuroimaging appears normal. Early and appropriate immunosuppressive therapy may help change the course of the disease and enhance patient outcomes.

Cerebellitis following COVID-19 infection: A case-based systematic review and pooled analysis.

Background: The COVID-19 pandemic has been linked to neurological complications, including Cerebellitis. This study aims to investigate the clinical features, and consequences of Cerebellitis following COVID-19 infection, informing medical management strategies. Methods: A systematic search was conducted through PubMed, Web of Science, Embase, ProQuest, and Cochrane databases from January 2018 to September 12, 2023, on cases post-COVID-19. Demographics, clinical characteristics, and diagnostic techniques were analyzed using descriptive statistics. Chi-Square tests assessed associations between diagnoses and treatments, with visualizations including heatmaps and scatter plots. Results: After the final Screening, the analysis of 18 cases revealed Cerebellitis post-COVID-19 spanned 9 countries, predominantly from the USA (27.8 %), with a mean patient age of 40.1 years (±24.6). Males comprised 94.4 % of cases. Common underlying conditions included hypertension (22.2 %) and diabetes (11.1 %). Neurological symptoms presented on average 15.15 ± 12.7 days post-COVID-19 infection. A moderate negative correlation (r = -0.358) was observed between age and symptom onset. Blood and CSF biomarkers showed weak correlations with symptom onset intervals. Treatment efficacy varied, with most cases achieving symptom-free outcomes. The Chi-Square test for diagnosis-treatment associations yielded a p-value of 0.089, and for follow-up outcomes, a p-value of 0.283, indicating no significant statistical associations. Conclusion: This systematic review highlights increased reports of Cerebellitis in males in their fourth decade of life, with the highest comorbidities being vascular diseases. Marker assessments show a decrease in CSF protein in half of patients, along with complete recovery following combination treatment with antivirals and steroids in acute Cerebellitis.

Comprehensive Physiotherapy Rehabilitation in a Patient With Cerebellar Ataxia and Dysphagia: A Case Report Investigating Symptomatology, Management, and Outcomes.

A cerebellar infarct occurs when blood flow to the cerebellum, located in the posterior cranial fossa, is disrupted. This diminished blood supply leads to decreased oxygen delivery, resulting in motor and balance control impairments. One prevalent sign of neurodegenerative diseases is dysphagia, which is typically linked to a higher death rate. No systematic and uniform assessment of dysphagia is used in the clinical care environment of individuals with ataxia. Its effect on the quality of life associated with health in patients is little understood. Therefore, this case report works to address dysphagia in cerebellar ataxia. This case report examines the physiotherapy management of a 41-year-old male who had cerebellar ataxia secondary to an infarct in the bilateral cerebellar hemisphere and vermis. The rehabilitation period lasted for six weeks. On examination, the patient had difficulty swallowing and showed symptoms of cerebellar dysfunctions, such as nystagmus, dyssynergia, dysmetria, and dysdiadochokinesia. Neuro-physiotherapy interventions, like conventional physiotherapy, trunk, and pelvis proprioceptive neuromuscular facilitation (PNF), Kinesio taping for dysphagia, interventions to treat gait, balance training interventions, and Frenkel's exercises were commenced. The outcome measures were evaluated using standardized outcome measures like the Swallowing Quality of Life Scale (SWAL-QOL), Severity of Ataxia Scale (SARA), Trunk Impairment Scale (TIS), Berg Balance Scale (BBS), Barthel Index, and World Health Organization Quality of Life (WHO-QOL). We conclude that a properly structured physiotherapy program subsequently improved the symptoms of patients. Furthermore, it enhanced functional independence, which subsequently improved the patient's quality of life.

Bromelain decreases oxidative stress and Neuroinflammation and improves motor function in adult male rats with cerebellar Ataxia induced by 3-acetylpyridine.

Bromelain is a plant-based molecule with antioxidant, antithrombotic, anticancer, and anti-inflammatory properties. Bromelain has been shown to reduce the release of inflammatory cytokines. This study aimed to determine whether bromelain can prevent ataxia in rats caused by 3-acetylpyridine (3-AP). Thirty-six albino rats were divided into the control, 3-AP, and 3-AP + Brom groups. In the 3-AP + Brom group, bromelain was injected intraperitoneally at 40 mg/kg daily for 30 days. Various techniques such as rotarod, electromyography (EMG), elevated plus maze, IHC, and Sholl analysis were used to evaluate the possible effects of bromelain on cerebellar neurons and glial cells. The results demonstrated significant improvements in most of the 3-AP + Brom, including motor coordination, neuromuscular response, anxiety, oxidative capacity, microgliosis, astrogliosis, cell death, and morphological variables compared to the 3-AP group. The mechanism of action of bromelain in restoring cerebellar ataxia needs further investigation, but it may be a candidate to help restore degeneration in animals with ataxia.

An overview of early-onset cerebellar ataxia: a practical guideline.

Early onset ataxias (EOAs) are a heterogeneous group of rare neurological disorders that not only involve the central and peripheral nervous system but also involve other organs. They are mainly manifested by degeneration or abnormal development of the cerebellum occurring before the age of 25 years and typically the pattern of inheritance is autosomal recessive.The diagnosis of autosomal recessive cerebellar ataxias (ARCAs) is confirmed by the clinical, laboratory, electrophysiological examination, neuroimaging findings, and mutation analysis when the causative gene is detected. Correct diagnosis is crucial for appropriate genetic counseling, estimating the prognosis, and, in some cases, pharmacological intervention. The wide variety of genotypes with a heterogeneous phenotypic manifestation makes the diagnostic work-up challenging, time-consuming, and expensive, not only for the clinician but also for the children and their parents. In this review, we focused on the step-by-step approach in which cerebellar ataxia is a prominent sign. We also outline the most common disorders in ataxias with early-onset manifestations.

Long-Term Follow-Up before and during Riluzole Treatment in Six Patients from Two Families with Spinocerebellar Ataxia Type 7.

BACKGROUND: Currently no curative treatment exists for spinocerebellar ataxias (SCAs). Riluzole repurposing was proposed as a symptomatic treatment in different types of cerebellar ataxia. We report a long-term-follow up under riluzole treatment in SCA type 7. METHODS: Six patients received Riluzole 50 mg twice daily on a compassionate use program for a mean of 4.8 years (range 3.5-9). We measured ataxia onset and progression through the Scale for the Assessment and Rating of Ataxia (SARA), and collected extensive ophthalmological data before and after Riluzole treatment. Electrocardiogram and laboratory profile for drug safety were performed every six months. RESULTS: Riluzole treatment showed no effect on visual function in two patients with an advanced retinal damage. Improvements of visual function occurred in four patients followed by ophthalmologic stability up to 5 years after starting treatment. Two patients had a less steep deterioration of ataxia after treatment compared to pre-treatment, during the first 2,5 years of therapy. One showed soon after therapy an improvement of the SARA score, and then overall stability lasting 3,5 years, followed by ataxia worsening. One visually impaired patient without neurological impairment did not worse until the last visit after 3,5 years of follow-up. The remaining 2 patients showed an improvement of SARA scores soon after therapy, and an overall stability lasting respectively 5 and 3 years. No adverse event was registered during the observation period. DISCUSSION: This study suggests a possible beneficial action of Riluzole in SCA7 and provides a detailed description of the ophthalmologic profile of these patients.

Streamlined two-step fragment analysis PCR and exome sequencing of RFC1 for diagnostic testing of suspected CANVAS patients.

Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) is caused by biallelic pathogenic expansions, or compound heterozygosity with other pathogenic variants in the RFC1 gene. CANVAS is estimated to be underdiagnosed, both because of the lack of formal diagnostic criteria and molecular challenges that translate to lesser access and high cost of routine testing. Our aim was to address the need for making CANVAS genetic testing routine, by designing a streamlined two-step PCR consisting of a short-allele screening PCR and a confirmatory PCR with fragment capillary electrophoresis detection. Exome sequencing of RFC1 was additionally foreseen to resolve potential compound heterozygosity cases. Specificity of our approach was evaluated using ataxia patients with known non-CANVAS diagnoses, and optimized using Southern blot confirmed CANVAS patients. We evaluated our approach by testing patients consecutively referred for clinically suspected CANVAS using first the two-step PCR, followed by exome sequencing. Our approach was able to accurately identify negative and confirm positive cases in prospectively collected suspected CANVAS patients presenting with at least three typical clinical signs. The proposed testing approach provides an alternative method able to clearly distinguish between CANVAS negative and positive cases and can be easily incorporated into the genetic diagnostic laboratory workflow.

COVID-19-Associated Cerebellar Ataxia: A Case Series.

COVID-19-associated cerebellar ataxia has rarely been reported and its clinical characteristics remain understudied. This study aims to report patients with COVID-19-associated cerebellar ataxia from our institution. COVID-19-associated cerebellar ataxia was diagnosed based on the prodromal COVID-19 infection and the exclusion of other causes. This study provides a summary of the patients' clinical presentations, neuroimaging features, and the results of anti-cerebellar antibody examinations. Our study included 11 patients and 4 were male. The median onset age was 38 years. Five patients also demonstrated signs of encephalopathy. Brain magnetic resonance imaging (MRI) was either unremarkable (n = 6) or showed bilateral cerebellar lesions (n = 5), which were typically transient, although brain atrophy could be observed later in the disease course. Anti-Homer-3 and anti-Yo antibodies were each detected in one patient, respectively. All patients received immunotherapy and nine improved. Compared with the late-onset group, individuals who exhibited ataxia earlier following COVID-19 onset (interval<5 days) were significantly younger [median age 18 (15.5-31) vs. 53.5 (44-64.8) years, p = 0.009] and more likely to present with encephalopathy (5/5 vs. 0/6, p = 0.002).They also experienced more severe symptoms [median modified Rankin scale (mRS) score at zenith 5 (5-5) vs. 2 (1.75-2.75), p = 0.017] and had a less favorable prognosis [median mRS score at the last follow-up 4 (2-5) vs. 1 (0-1.25), p = 0.009]. COVID-19-associated cerebellar ataxia can appear with encephalopathy. Brain MRI may show transient bilateral cerebellar lesions and brain atrophy later. Patients who exhibited ataxia earlier following COVID-19 were younger, had more severe symptoms and poorer outcomes.

External Laryngeal Tremor in Adult-Onset Alexander Disease: A Case Report.

Introduction: Alexander disease is caused by mutations in GFAP, the glial fibrillary acidic protein gene. External laryngeal tremor has not been reported in adult-onset Alexander disease (AOAxD). The aims of this work were to report one such case and to review the literature on palatopharyngeal tremor and AOAxD. Case Presentation: A 43-year-old man experienced involuntary movements at the front of his neck. Continuous, rhythmic vertical movements of the laryngeal skeleton, soft palate and tongue, and lower limb dysmetria were observed. The pathogenic GFAP variant c.994G>A; p.(Glu332Lys) was found. MRI demonstrated spinal cord and medulla oblongata atrophy and hyperintensities at the cerebellum and cerebral white matter. Conclusion: External laryngeal, palatopharyngeal tremor and cerebellar ataxia constituted a mild phenotype, as expected from this variant, herein reported in isolation for the third time. Imaging was consistent with AOAxD, including the so-called tadpole sign. Additional studies are necessary to define this infrequent disease.

Phenotypic variability related to dominant UCHL1 mutations: about three families with optic atrophy and ataxia.

INTRODUCTION: Ubiquitin C-terminal hydrolase L1 (UCHL1) has been associated with a severe, complex autosomal recessive spastic paraplegia (HSP79) [1] [2] [3] [4]. More recently, UCHL1 loss of function (LoF) variants have been associated to an autosomal dominant disease characterized by late-onset spastic ataxia, neuropathy, and frequent optic atrophy [5]. METHODS: Routine clinical care whole-genome (WGS) and exome (ES) sequencing. RESULTS: We present three families with autosomal dominant UCHL1-related disorder. The clinical phenotype mainly associated optic atrophy, mixed cerebellar and sensory ataxia, and possible hearing loss. We delineated two major phenotypes, even within the same family: (1) juvenile severe optic atrophy followed by a later-onset ataxia, or (2) late-onset ataxia with asymptomatic or mild optic atrophy. The families harboured three novel heterozygous variants in UCHL1: two loss of function (p.Lys115AsnfsTer40; c.171_174 + 7del11), and one missense (p.Asp176Asn) involving the catalytic site of the protein and potentially altering the adjacent splice site. DISCUSSION: We confirm the existence of dominantly inherited UCHL1 pathogenic variants. We describe a considerable intrafamilial phenotypic variability, with two main phenotypes. Optic atrophy was consistently present, but with varying degrees of severity. Neither delayed motor or intellectual development, nor dysmorphic features were part of the dominant phenotype in comparison with the autosomal recessive form. The molecular mechanism appears to be haploinsufficiency. UCHL1 monoallelic variants should therefore be considered in any case of early-onset optic atrophy or in late-onset complex ataxic syndrome with asymptomatic optic atrophy.

Cerebellar form of multiple system atrophy: A case report.

Multiple system atrophy is a form of synucleinopathy with an unknown etiology that causes progressive neurodegeneration. It may affect the cerebellum, autonomic nerves, and pyramidal and extrapyramidal systems. We present the case of a 51-year-old man who was hospitalized for recurrent balance problems and dizziness. Cranial magnetic resonance imaging showed the "hot cross bun" sign of the pons with major atrophy of the cerebellum. The cerebellar form of probable multiple system atrophy was the final diagnosis.

Acute Cerebellitis and Obstructive Hydrocephalus: An Unseen Neurological Complication After Surgical Repair for Tetralogy of Fallot.

Acute cerebellitis with obstructive hydrocephalus post-Tetralogy of Fallot surgery is extremely rare but can present aggressively in pediatric cases. Early diagnosis is critical for prompt medical and surgical intervention. We report a fatal case in a 7-year-old boy post-surgery, where neurological symptoms rapidly progressed, leading to drowsiness and intermittent response to commands. Despite initial computed tomography scans showing no abnormality, subsequent scans revealed cerebellitis and hydrocephalus. Treatment with steroids, antibiotics, and cerebrospinal fluid drainage was unsuccessful, and the condition's etiology remained unclear despite negative serological tests and cultures. This highlights the challenge of diagnosing and treating acute cerebellitis, especially when no specific cause is found and when deterioration is swift. The role of opioids in pediatric patients and their potential association with neurosurgical complications is also discussed, prompting further inquiry into postoperative symptoms and opioid-related risks in susceptible individuals.

Might patients with cerebellar ataxia benefit from the Computer Assisted Rehabilitation ENvironment (CAREN)? A pilot study focusing on gait and balance.

Introduction: Ataxia is a neurological symptom that causes decreased balance, loss of coordination, and gait alterations. Innovative rehabilitation devices like virtual reality (VR) systems can provide task-oriented, repetitive and intensive training with multisensorial feedback, thus promoting neuroplastic processes. Among these VR technologies, the Computer Assisted Rehabilitation ENvironment (CAREN) associates a split belt treadmill on a 6-degrees of freedom platform with a 180° VR screen and a Vicon motion capture system to monitor patients' movements during training sessions. Methods: Eight patients affected by cerebellar ataxia were enrolled and received 20 sessions of CAREN training in addition to standard rehabilitation treatment. Each patient was evaluated at the beginning and at the end of the study with 3D gait analysis and clinical scales to assess balance, gait function and risk of falls. Results: We found improvements in kinematic, kinetic, and electromyographic parameters (as per pre-post- CAREN training), as well as in clinical outcomes, such as balance and risk of falls in ataxic patients. In addition, we found that trunk rotation improved, after CAREN intervention, approximating to the normative values. Discussion: Our results suggested that CAREN might be useful to improve specific biomechanical parameters of gait in ataxic patients.