Immune-mediated encephalitis following SARS-CoV-2 vaccinations.

OBJECTIVES: one of the neurological side effects of SARS-CoV-2 vaccinations is immune encephalitis. This review aims at summarising previous and current findings on the frequency, clinical presentation, diagnosis, treatment, and outcome of SARS-CoV-2 vaccination-associated encephalitis (SC2VIE). METHODS: narrative review of eligible articles meeting defined search criteria and published between January 2021 and January 2024. RESULTS: A total of 21 patients with SC2VIE reported in 18 articles were included. The AstraZeneca vaccine (ChAdOx1) was the trigger in 10 cases, the Biontech Pfizer vaccine (BNT162b2) in 8 cases, and the Moderna (mRNA1273), CoronaVac, and Sinopharm vaccine (BBIBP-CorV) in one case each. The ages ranged from 21 to 82 years. Twelve patients were female. SC2VIE developed after the first dose in eight patients, after the second in six patients, and in two after the third dose. The latency between vaccination and onset of clinical manifestations ranged from 1 to 56d. Eighteen patients received steroids, one patient intravenous immunoglobulins, one patient plasmapheresis, and two patients rituximab. Complete recovery was achieved in nine patients and incomplete recovery in ten. CONCLUSIONS: SC2VIE is not an uncommon complication of SARS-CoV-2 vaccinations. The clinical presentation and treatment of SC2VIE do not differ from those of autoimmune encephalitis of other causes. Since SC2VIE can manifest only as a psychiatric disease, patients with post-SARS-CoV-2 vaccination psychosis should be evaluated for SC2VIA. The outcome of SC2VIE depends largely on the severity of the immune response and comorbidities.

SARS-CoV-2 vaccinations reduce the prevalence of post-COVID Guillain-Barre syndrome.

Guillain-Barre Syndrome (GBS) has been repeatedly reported as a neurological complication of COVID-19 (post-COVID GBS [PCG]). Whether the introduction of SARS-CoV-2 vaccines reduced the prevalence of PCG is unknown. This narrative review aimed to compare the number of published PCG cases between the second half of 2020 (no vaccination available) with those of the first half of 2021 (vaccination available). A total of 124 articles reported 300 patients with PCG between January 2020 and June 2021. The ages ranged from 7 to 94y. There was male dominance. The latency between the onset of COVID-19 and the onset of PCG ranged from -10 to 90d Acute, inflammatory, demyelinating polyneuropathy was diagnosed in 171 patients, acute, motor axonal neuropathy in 24, and acute, motor, and sensory axonal neuropathy in 16 patients. Regarding treatment, 241 patients received immunoglobulins, 28 patients' plasmaphereses, and 7 patients' steroids. Artificial ventilation was required in 59 patients. Full recovery was achieved in 42 cases, partial recovery in 163 cases, and 17 patients died. The number of published PCG patients fell from 192 in the second half of 2020 to 75 patients in the first half of 2021. It is concluded that the prevalence of PCG has decreased since the introduction of SARS-CoV-2 vaccines. SARS-CoV-2 vaccinations have a positive effect on the prevalence of PCG.

Differences in Evolution of Epileptic Seizures and Topographical Distribution of Tissue Damage in Selected Limbic Structures Between Male and Female Rats Submitted to the Pilocarpine Model.

Epidemiological evidence shows that clinical features and comorbidities in temporal lobe epilepsy (TLE) may have different manifestations depending on the sex of patients. However, little is known about how sex-related mechanisms can interfere with the processes underlying the epileptic phenomenon. The findings of this study show that male rats with epilepsy in the pilocarpine model have longer-lasting and more severe epileptic seizures, while female rats have a higher frequency of epileptic seizures and a greater number of seizure clusters. Significant sex-linked pathological changes were also observed: epileptic brains of male and female rats showed differences in mass reduction of 41.8% in the amygdala and 18.2% in the olfactory bulb, while loss of neuronal cells was present in the hippocampus (12.3%), amygdala (18.1%), and olfactory bulb (7.5%). Another important sex-related finding was the changes in non-neuronal cells with increments for the hippocampus (36.1%), amygdala (14.7%), and olfactory bulb (37%). Taken together, our study suggests that these neuropathological changes may underlie the differences in the clinical features of epileptic seizures observed in male and female rats.

SARS-CoV-2 vaccinations reduce the prevalence of post-COVID Guillain-Barre syndrome

Abstract Guillain-Barre Syndrome (GBS) has been repeatedly reported as a neurological complication of COVID-19 (post-COVID GBS [PCG]). Whether the introduction of SARS-CoV-2 vaccines reduced the prevalence of PCG is unknown. This narrative review aimed to compare the number of published PCG cases between the second half of 2020 (no vaccination available) with those of the first half of 2021 (vaccination available). A total of 124 articles reported 300 patients with PCG between January 2020 and June 2021. The ages ranged from 7 to 94y. There was male dominance. The latency between the onset of COVID-19 and the onset of PCG ranged from -10 to 90d Acute, inflammatory, demyelinating polyneuropathy was diagnosed in 171 patients, acute, motor axonal neuropathy in 24, and acute, motor, and sensory axonal neuropathy in 16 patients. Regarding treatment, 241 patients received immunoglobulins, 28 patients' plasmaphereses, and 7 patients' steroids. Artificial ventilation was required in 59 patients. Full recovery was achieved in 42 cases, partial recovery in 163 cases, and 17 patients died. The number of published PCG patients fell from 192 in the second half of 2020 to 75 patients in the first half of 2021. It is concluded that the prevalence of PCG has decreased since the introduction of SARS-CoV-2 vaccines. SARS-CoV-2 vaccinations have a positive effect on the prevalence of PCG. HIGHLIGHTS SARS-CoV-2 infections can be complicated by Guillain-Barre Syndrome (GBS). The prevalence of SARS-CoV-2 associated GBS declined since the introduction of SARS-CoV-2 vaccines. The outcome of SARS-CoV-2 associated GBS is worse among those with comorbidities compared to those without.

Seizure vulnerability and anxiety responses following chronic co-administration and acute withdrawal of caffeine and ethanol in a rat model.

BACKGROUND: Caffeine antagonizes the intoxicating effects of alcohol. Consequently, there has been a dramatic global increase in the consumption of caffeinated drinks together with alcohol, especially among young adults. We assessed the seizure vulnerability and anxiety responses following the chronic co-administration of, and withdrawal from, caffeine and ethanol in male rats. METHODS: The rats were randomly assigned to six groups consisting of 10 animals each: 10 mg/kg of caffeine, 20 mg/kg of caffeine, 4 g/kg of 20% ethanol, combined caffeine (20 mg/kg) and ethanol (4 g/kg of 20%), 4 mL/kg distilled water, and an untreated control group. The test substances were administered intragastrically twice daily for 29 days. On day 29, the rats were tested on the elevated plus maze to assess anxiety-related responses. On day 30, pentylenetetrazol (PTZ), a chemoconvulsant, was administered intraperitoneally at a dose of 40 mg/kg to the animals. Seizure responses and mortality up to 72 h were recorded. RESULTS: Compared with the control group, the rats that received chronic treatment with low-dose caffeine, ethanol alone, and combined caffeine and ethanol exhibited significant anxiogenic-like effects, unlike with high-dose caffeine. Both low- and high-dose caffeine significantly increased PTZ seizure latency. Ethanol alone and combined caffeine and ethanol both lowered PTZ seizure latency. No significant difference occurred between the controls and the untreated group for either anxiety or seizure expression. Combined caffeine and ethanol increased the seizure-induced mortality from withdrawal effects at 72 h. CONCLUSIONS: These findings suggest that the chronic co-administration of caffeine and ethanol and the acute withdrawal from these drugs lead to anxiogenic effects and increased seizure vulnerability.

Projection neurons in the cortex and hippocampus: differential effects of chronic khat and ethanol exposure in adult male rats.

BACKGROUND: Recent evidence suggests that many individuals who chew khat recreationally also drink ethanol to offset the stimulating effect of khat. The objective of this study was to describe the separate and interactive effects of chronic ethanol and khat exposure on key projection neurons in the cortex and hippocampus of young adult male rats. METHODS: Young adult male Sprague Dawley rats were divided into six treatment groups: 2 g/kg khat, 4 g/kg khat, 4 g/kg ethanol, combined khat and ethanol (4 g/kg each), a normal saline control, and an untreated group. Treatments were administered orally for 28 continuous days; brains were then harvested, sectioned, and routine hematoxylin-eosin staining was done. Following photomicrography, ImageJ® software captured data regarding neuron number and size. RESULTS: No differences occurred in counts of both granular and pyramidal projection neurons in the motor cortex and all four subfields of the hippocampal formation. Khat dose-dependently increased pyramidal neuron size in the motor cortex and the CA3 region, but had different effects on granular neuron size in the dentate gyrus and the motor cortex. Mean pyramidal neuron size for the ethanol-only treatment was larger than that for the 2 g/kg khat group, and the saline control group, in CA3 and in the motor cortex. Concomitant khat and ethanol increased granular neuron size in the motor cortex, compared to the 2 g/kg khat group, the 4 g/kg khat group, and the 4 g/kg ethanol group. In the CA3 region, the 4 g/kg ethanol group showed a larger mean pyramidal neuron size than the combined khat and ethanol group. CONCLUSION: These results suggest that concomitant khat and ethanol exposure changes granular and pyramidal projection neuron sizes differentially in the motor cortex and hippocampus, compared to the effects of chronic exposure to these two drugs separately.