Emerging Neurologist

Prevalence and overlap of potential embolic sources in embolic stroke of undetermined source: a retrospective cohort

Mouna Nagazi — 2022-11-28

Introduction: Embolic strokes of an undetermined source may be caused by various potential embolic sources, which can be better managed by anticoagulant or antiplatelet therapy. Identifying these sources may have diagnostic and therapeutic implications. Our objectives were to assess the prevalence and overlap of different potential embolic sources identified in a population of patients with embolic strokes of undetermined sources, and to evaluate the stroke recurrence rate according to the type and number of potential embolic sources.

Methods: We used data from consecutive patients with ischemic stroke admitted to the department of neurology in Fattouma Bourguiba hospital (Monastir, Tunisia), between January 2017 and December 2020. Patients who met the embolic strokes of undetermined source diagnostic criteria according to the criteria of the Cryptogenic Stroke “embolic strokes of undetermined source” International Working Group were selected. The presence of each potential embolic source was assessed, and patients were categorised according to the identified potential embolic sources. The main outcome was ischemic stroke recurrence, and it was collected prospectively during follow-up after the index stroke.

Results: Among 330 patients admitted between 2017 and 2020, 66 (20.6%) were classified as embolic strokes of undetermined source (68.2% were men, mean age 57 ±11 years). The three most prevalent potential embolic sources were atrial cardiopathy (N = 47/66; 71.2%), arterial atherosclerosis (N = 46/66; 69.7%) and left ventricular disease (N = 26/66; 39.4%). Most patients (N = 56/66; 84.8%) had ≥2 potential embolic sources. After 6-month of follow up, ischemic stroke recurrence occurred in 18 (27.3%) patients. In survival analysis, the type and the number of potential embolic sources were not statistically associated with stroke recurrence.

Conclusion: Most patients with embolic strokes of undetermined source had multiple potential embolic sources, which overlap considerably. The type and number of potential sources were not associated with stroke recurrence. This finding may explain the negative results of large trials of secondary prevention in the Embolic strokes of undetermined source population.

Publishing and Neurology: History driven by young practitioners

Leila Ali — 2022-11-28

Unusual flare up of Susac syndrome

Malek Mansour — 2022-11-28

Introduction. Spinal cord involvement as a flare-up of Susac syndrome (SuS) is rarely reported in the literature. The pathogenesis of SuS includes multiple occlusions in micro vessels mediated by an autoimmune response to unknown antigens. This condition is characterized by a triad: central nervous system (CNS) dysfunction with a frequent involvement of the corpus callosum in brain MRI, visual disturbances due to branch retinal artery occlusion, and sensorineural hearing impairment.

Case report. A 50-year-old man presented in December 2019 symptoms associating gait instability, diplopia and hypoacusis. A year later, he developed a vesical-sphincter disorder and a hypoesthesia in his right lower limb. Neurological examination identified a medullary syndrome, cerebellar ataxia and hypoacusis. We performed a brain and spinal MRI showing supratentorial and infratentorial white matter lesions, and gadolinium enhancing cervical lesions. Lumbar puncture with isoelectric focusing results was normal. Screening for differential diagnosis such as other inflammatory central nervous system diseases other than multiple sclerosis was performed considering this atypical presentation of the disease; workup of serological, immunological, angiotensin converting enzyme, and tumor markers was negative. A bilateral hearing deficit was confirmed with an audiogram. Retinal angiography showed ischemic retinal vasculitis. We diagnosed the patient with SuS and treated him with intravenous corticosteroids in transition to oral corticosteroids. We noticed a partial regression of his symptoms. Therefore, we highlight the importance of an early diagnosis for SuS to avoid a prognostic turnover of the disease. Spinal cord involvement should not rule out the diagnosis of SuS.

Clinical and electrophysiological pattern of startle epilepsy: a comprehensive literature review

Margaux Cheval — 2022-11-28

Startle epilepsy is a rare form of epilepsy characterized by recurrent seizures that are triggered by a surprising stimulus. It affects children between 10 months and 14 years of age, with a history of brain damage due to ante- or neonatal hypoxia, and hemiparesis. The most common triggers for these seizures are auditory stimulation, followed by somesthetic stimulation and visual stimulation. Typical startle seizures are rare, and they have a large variety of clinical manifestations. The most frequent type is short hemitonic flexion seizures, followed by myoclonic seizures, and bilateral tonic seizures.

Few studies have focused on the electrophysiological features of this condition and the literature is controversial regarding the EEG pattern. Interictal EEG is often normal. The most frequent interictal abnormalities are a slowing of the background rhythm, associated with focal spikes in the frontal, central, and parietal regions. Several ictal EEG patterns have been reported: diffuse flattening of the background rhythm, focal fast activity, an isolated focal spike followed by a discharge of spikes. Intracerebral EEG recording shows primary and secondary motor cortex involvement as initial discharge areas. The most efficient antiepileptic drugs are Lamotrigine, Oxcarbazepine, and benzodiazepines. But most patients are often drug-resistant. Surgery is a possible albeit rare therapeutic option.

We describe the case of a 13-year-old female patient with hemitonic seizures triggered by surprising auditory stimuli. The video EEG allowed us to record and define an EEG pattern of her seizures. Interictal EEG showed right fronto-central abundant spikes. The ictal EEG showed right fronto-central and medial spikes followed by a fronto-central fast rhythm discharge. The clinical and electrographic data permitted the diagnosis of startle epilepsy. Our patient was treated with Levetiracetam during 6 months followed by Oxcarbazepine and Clobazam with a partial improvement (reduction of the frequency of focal to bilateral tonic-clonic seizures). Considering the usual pharmaco-resistance of this type of epilepsy, we proposed our patient a presurgical evaluation. This case shows that the diagnosis should be considered in paroxysmal dystonic movements with a stereotyped triggering factor, and underlines the importance of repeating the EEG recordings in this type of epilepsy. In this article we will review the literature, discuss the underlying pathophysiology, and identify the common electrophysiological characteristics associated with startle epilepsy.