Gerstmann-Straussler-Scheinker (GSS) disease is a rare hereditary autosomal dominant prion disease characterized by cerebellar ataxia, dysarthria, and progressive dementia. We report a case of GSS disease in a 46-year-old patient who presented with four to six months of ataxia, dysarthria, intermittent tongue biting, and frontal headaches. His DaTscan (dopamine transporter scan) showed absent dopamine uptake in the left putamen and mildly decreased activity in the right putamen, a finding that has only been documented in the literature one other time for this GSS variant. Family history included the death of his father at age 58 from presumed multiple system atrophy (MSA). His symptoms and family history of parkinsonism prompted genetic testing, which revealed a F198S variant in the prion protein gene (PRNP), confirming a diagnosis of GSS disease.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by degeneration of the upper and lower motor neurons, with respiratory muscle involvement typically occurring in the later stages of the disease. Presentation with acute hypercapnic respiratory failure as the initial clinical manifestation is uncommon and frequently leads to diagnostic delay or misattribution to primary cardiopulmonary pathology. We present the case of a 60-year-old man with no prior respiratory history who presented with acute dyspnea and was found to have severe hypercapnic respiratory failure requiring urgent noninvasive ventilation. Clinical examination and initial investigations revealed no clear intrinsic pulmonary cause. A detailed history subsequently identified a four-month progression of neurological symptoms, including dysarthria, sialorrhea, asymmetric upper limb weakness, and significant unintentional weight loss. Neurological examination demonstrated tongue fasciculations, widespread muscle wasting, and a combination of upper and lower motor neuron signs. Following acute stabilization and discharge with domiciliary noninvasive ventilation, a specialist neurological assessment confirmed a diagnosis of ALS. This case highlights the clinical importance of considering underlying neuromuscular causes in patients presenting with unexplained hypercapnic respiratory failure, particularly when clinical findings are discordant with the severity of the gas exchange abnormalities. Early recognition of ALS in this context facilitates the timely initiation of ventilatory support and multidisciplinary care, which are essential for optimizing survival and quality of life.

Pontine warning syndrome describes recurrent, transient neurological episodes arising from pontine pathology and carries a high risk of subsequent infarction. We report the case of a 102-year-old woman who presented with repeated, stereotyped episodes of unilateral weakness and dysarthria before developing a confirmed pontine infarct. Early CT imaging was normal, and the diagnosis was established only after MRI demonstrated an acute brainstem lesion. Her clinical course reflects previously described patterns of fluctuating deficits linked to pontine perforator disease, intermittent hypoperfusion, and sensitivity to blood pressure changes. She was treated with dual antiplatelet therapy and made a complete recovery. This case highlights the importance of recognising pontine warning syndrome promptly, as early localisation guides imaging strategy, monitoring, and management.

Guillain-Barré syndrome (GBS) is an immune-mediated disorder of the peripheral nervous system characterized by progressive weakness and often triggered by infections. GBS has an estimated mortality rate of approximately 5%, with a worldwide incidence of 0.81-1.91 cases per 1,00,000 person-years. This case reported a 23-year-old man presented with progressive weakness in all four extremities. An initial neurological examination revealed bilateral total ophthalmoplegia, ptosis on both eyes, bilateral facial palsy lower motor neuron (LMN) type, dysarthria, dysphagia, flaccid tetra-paresis, gloves, and stocking paresthesia. Lumbar puncture showed cytoalbumin dissociation. Nerve conduction studies showed a demyelinating sensorimotor polyradiculoneuropathy lesion. The patient received intravenous immunoglobulin (IVIG) treatment 0.4 g/kg/day for 5 days, physical rehabilitation therapy, nutritional support, multidisciplinary care involving anesthesiology and intensive care teams, and other symptomatic treatments. At five-month follow-up, the patient demonstrated complete recovery. GBS typically presents as an acute ascending sensorimotor neuropathy; however, atypical presentations may occur. Extensive cranial nerve involvement-including complete ophthalmoplegia, bilateral facial palsy, and bulbar dysfunction-in AIDP is uncommon and may mimic other GBS spectrum disorders. Early recognition, prompt immunotherapy, and careful electrophysiological evaluation are essential for optimizing patient outcomes. Because electrodiagnostic classification of GBS may evolve over time, serial nerve conduction studies should be considered whenever feasible to improve subtype classification and diagnostic confidence.

The high-intensity focused ultrasound (HIFU) technique has become precise, incisionless, and ablative for treating essential tremor (ET) and Parkinson's disease (PD), driven by advances in magnetic resonance imaging (MRI) thermometry and tractography. The current review integrates the main clinical outcomes associated with established and emerging HIFU targets, synthesizing efficacy data, adverse effect (AE) patterns, and procedural characteristics relevant to clinical decision-making. In ET, ventral intermediate nucleus (VIM) thalamotomy results in tremor reductions ranging from 56 to 81%, with a long-term sustained benefit of approximately 73%. In tremor-dominant PD (TdPD), VIM ablation achieves tremor suppression of approximately 62%. Comparatively, HIFU-guided subthalamotomy provides broader motor benefits, with 53 to 57.8% improvement in the Movement Disorder Society's Unified Parkinson's Disease Rating Scale, Part III (MDS-UPDRS III), as well as significant reductions in rigidity and bradykinesia. Pallidotomy improves "off" state motor symptoms and dyskinesias, whereas pallidothalamic tractotomy leads to 52% global motor improvement and 91% tremor reduction. The AEs vary according to the targets. In VIM procedures, gait imbalance (16-40%) and sensory disturbances (9-26%) predominate, along with dysarthria and dysmetria. Lesions to the subthalamic nucleus (STN) are most commonly associated with dysarthria (10-26%) and gait instability (15-48%). Procedures targeting the globus pallidus internus (GPi) or pallidothalamic tract (PTT) may also present with gait instability or dysarthria, which are generally mild and transient. Although the SDR has historically limited eligibility, recent evidence demonstrates that patients with SDR ≤ 0.40 may still experience meaningful improvement, supporting more individualized selection. In the current therapeutic landscape, HIFU offers immediate clinical benefits, absence of implanted hardware, and simplified recovery, positioning it as an alternative or complementary therapy to deep brain stimulation (DBS).

Lacunar strokes are small subcortical infarcts that result from the occlusion of small perforating arteries, and they comprise about 25% of all strokes. Unlike other types of infarcts, lacunar strokes are primarily due to cerebral small vessel disease. Detection of acute lacunar infarcts may be challenging due to their small size, but it can be improved with clinical-radiologic correlation. Numerous mimics should also be kept in mind in the differential diagnosis. While lacunar infarcts are more often asymptomatic, they may manifest with distinct clinical syndromes. Five classic lacunar syndromes are commonly recognized: pure motor hemiparesis, pure sensory stroke, sensorimotor stroke, ataxic hemiparesis, and dysarthria-clumsy hand syndrome. Beyond these, numerous atypical lacunar syndromes such as internuclear ophthalmoplegia, isolated dysarthria, hemichorea and hemiballismus, and paramedian thalamic syndrome have been described. Each of these has a unique clinical manifestation linked to lesions in specific neuroanatomic pathways. The authors provide a comprehensive overview of lacunar strokes, emphasizing their diverse clinical manifestations and the crucial role of imaging in diagnosis of these infarcts. ©RSNA, 2026 Supplemental material is available for this article.

Varicella-zoster virus (VZV) meningitis has been reported during treatment with amenamevir (AMNV). Although case reports have raised concerns about its ability to prevent central nervous system (CNS) complications, cerebrospinal fluid (CSF) penetration has not been evaluated. We report the first case of VZV meningitis with measured CSF AMNV concentration. An 80-year-old man developed altered consciousness and dysarthria on day 7 of AMNV therapy for thoracic herpes zoster. The CSF AMNV concentration on admission was 0.086 µmol/L (41.3 ng/mL), measured 20-24 h after the last dose, within the reported in vitro half-maximal effective concentration (EC50) range for VZV (0.055-0.10 µmol/L) in Japan; however, the clinical relevance of this comparison remains uncertain. The patient's condition improved rapidly after initiation of acyclovir therapy. This case provides the first direct evidence that AMNV reaches the CSF. However, whether CSF exposure is sufficient to prevent CNS complications or attenuate disease severity remains unclear.

Primary familial brain calcification (PFBC) is a rare inherited neurological disorder characterized by bilateral intracranial calcifications and heterogeneous clinical manifestations. MYORG-related PFBC is a recently identified autosomal recessive subtype; however, its metabolic abnormalities and dopaminergic function remain incompletely characterized. We report a 45-year-old man with progressive parkinsonism, dysarthria, and a history of recurrent limb twitching. Genetic analysis identified a novel homozygous frameshift variant in MYORG (c.348_352dup, p.Gly118AlafsTer76), confirming the diagnosis of MYORG-related PFBC. Multimodal positron emission tomography (PET), including fluorine-18 fluorodeoxyglucose ([18]F-FDG) PET and fluorine-18 fluoropropyl-carbomethoxy iodophenyl tropane ([18]F-FP-CIT) PET, was performed to assess cerebral glucose metabolism and presynaptic dopaminergic function. [18]F-FDG PET demonstrated reduced metabolism in the right caudate nucleus and cerebellum, whereas [18]F-FP-CIT PET showed preserved striatal dopamine transporter availability. These findings suggest that parkinsonian symptoms in this patient with MYORG-related PFBC may be associated with dysfunction of the striato-cerebellar pathways rather than presynaptic nigrostriatal degeneration. This case expands the genetic spectrum of MYORG-related PFBC and highlights the potential value of combined metabolic and dopaminergic PET imaging for evaluating movement disorders associated with PFBC.

An 85-year-old, HIV-seronegative woman presented with subacute right-sided weakness and dysarthria. Neuroimaging revealed multiple rim-enhancing intracranial mass lesions, initially attributed to metastatic disease of unknown primary. Subsequent biopsy and excision yielded purulent material with abundant acid-fast bacilli; culture and molecular testing confirmed Mycobacterium tuberculosis. Histopathology demonstrated an exceptionally high mycobacterial burden and an absence of well-formed epithelioid granulomas, establishing a diagnosis of tuberculous brain abscess. A 12-month anti-tuberculosis therapy led to clinical and radiological resolution. This case illustrates an uncommon presentation of central nervous system tuberculosis that can closely mimic intracranial malignancy.