Recrudescence of severe polyneuropathy after receiving Pfizer-BioNTech COVID-19 vaccine in a patient with a history of eosinophilic granulomatosis with polyangiitis.

A middle age man with a history of diabetes mellitus type 2, hypertension, migraine and eosinophilic granulomatosis with polyangiitis (EGPA) with polyneuropathy in remission presented with paresthesia and motor weakness soon after receiving the Pfizer-BioNTech COVID-19 messanger RNA (mRNA) vaccine. The patient had polyneuropathy 10 years ago secondary to EGPA, which had resolved. EGPA was diagnosed on the basis of typical symptoms and positive sural nerve biopsy. Five days after receiving the first dose of COVID-19 vaccine, he developed heaviness and reduced dexterity of both the upper extremities, which progressed to patchy and asymmetric motor weakness of all four extremities. Given the lack of clear alternative explanation after a thorough work up, recrudescence of underlying asymptomatic polyneuropathy due to a possible reaction to COVID-19 mRNA vaccine was considered although a temporal association with vaccine dose does not prove causality. He was treated with corticosteroids with slow improvement of his symptoms.

Paraneoplastic seesaw nystagmus and opsoclonus provides evidence for hyperexcitable reciprocally innervating mesencephalic network.

Seesaw nystagmus is characterized by the rhythmic combination of vertical and torsional dysconjugate oscillations where one eye moves up and inward while the other moves down and outward. Common association of seesaw nystagmus with accessory optic track lesions lead to traditional hypothesis that it is due to the mismatch in the vision and vestibular systems. Here we propose a novel mechanism for seesaw nystagmus. We hypothesize that reverberations due to abnormal increases in the excitability of the reciprocally innervating circuit of excitatory burst neuron in the midbrain interstitial nucleus of Cajal causes the seesaw nystagmus. Analogous oscillations of the brainstem burst generators may be responsible for generation of saccadic oscillations or opsoclonus. The key difference is that the interstitial nucleus of Cajal lacks inhibitory burst neurons, hence the lack of post-inhibitory rebound, and relatively lower frequency of the oscillatory cycles causing pendular seesaw nystagmus. In contrast the brainstem burst generator, with reciprocally innervating excitatory and inhibitory burst neurons, and further inhibitory influence of the omnipause neurons results in the post-inhibitory rebound at the burst neurons, hence high oscillation frequency. This novel concept is supported by a unique observation in a patient with antineuronal nuclear autoantibody type 2 due to breast cancer who had combined seesaw nystagmus and superimposed saccadic oscillations. The patient neither had cerebellar deficits typically thought to cause paraneoplastic opsoclonus nor visual deficits that are known cause of seesaw nystagmus. We propose that hyperexcitability of the burst neurons in the interstitial nucleus of Cajal due to paraneoplastic antibody caused pendular seesaw nystagmus. On the other hand, increased excitability of brainstem burst generators and reduced efficacy of the omnipause neurons caused saccadic oscillations.

Generalized Periodic Discharges With and Without Triphasic Morphology.

PURPOSE: Generalized periodic discharges (GPDs) with a triphasic morphology have been associated with nonepileptic encephalopathies. We conducted the study to assess the reliability in which electroencephalographers can differentiate triphasic from nontriphasic periodic discharges and to evaluate for the presence of electroencephalogram and clinical characteristics that are associated with a higher risk of seizures. METHODS: We studied prospectively 92 patients between May 2016 and February 2017. Each pattern was analyzed by two readers, who were blinded to clinical data. RESULTS: The interrater agreement was "substantial" (Kappa 0.67). The following features significantly increased the risk of developing seizures: the absence of triphasic morphology, focality on electroencephalogram, interburst suppression, a history of epilepsy, and an abnormal scan. The "GPD score" includes a history of epilepsy, focality on electroencephalogram, and the absence of triphasic morphology. A GPD score of 0 has 13% risk of seizures, whereas a score of 5 to 6 has a 94% risk. CONCLUSIONS: Triphasic morphology GPDs confer less risk of seizures when compared with patients with GPDs without triphasic morphology. Features with a higher risk of seizures include focality on electroencephalogram, interburst suppression, a history of epilepsy, and an abnormal scan. The GPD score can be used to assess the risk of developing seizures in patients with GPDs.

Acute Ischemic Pediatric Stroke Management: An Extended Window for Mechanical Thrombectomy?

Ischemic stroke is a rare condition to afflict the pediatric population. Congenital cardiomyopathy represents one of several possible etiologies in children. We report a 9-year-old boy who developed right middle cerebral artery stroke secondary to primary restrictive cardiomyopathy. In the absence of pediatric guidelines, the child met adult criteria for mechanical thrombectomy given the small core infarct and large penumbra. The literature suggests children may benefit from mechanical thrombectomy in carefully selected cases. Our patient exemplifies specific circumstances in which acute stroke therapy with thrombolysis and thrombectomy may be safe.