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BACKGROUND: SARS-CoV-2 posed a threat to children during the early phase of Omicron wave because many patients presented with febrile seizures. The study aimed to investigate predicting factors for acute encephalopathy of children infected by SARS-CoV-2 Omicron variant presenting with febrile seizures. METHODS: The retrospective study analyzed data from pediatric patients who visited the emergency department of Chang Gung Memorial Hospital in Taiwan between April and July 2022. We specifically focused on children with COVID-19 who presented with febrile seizures, collecting demographic, clinical, and laboratory data at the pediatric emergency department, as well as final discharge diagnoses. Subsequently, we conducted a comparative analysis of the clinical and laboratory characteristics between patients diagnosed with acute encephalopathy and those with other causes of febrile seizures. RESULTS: Overall, 10,878 children were included, of which 260 patients presented with febrile seizures. Among them, 116 individuals tested positive for SARS-CoV-2 and of them, 14 subsequently developed acute encephalopathy (12%). Those with acute encephalopathy displayed distinctive features, including older age (5.1 vs. 2.6 years old), longer fever duration preceding the first seizure (1.6 vs. 0.9 days), cluster seizure (50% vs. 16.7%), status epilepticus (50% vs. 13.7%) and occurrences of bradycardia (26.8% vs. 0%) and hypotension (14.3% vs. 0%) in the encephalopathy group. Besides, the laboratory findings in the encephalopathy group are characterized by hyperglycemia (mean (95% CI) 146 mg/dL (95% CI 109-157) vs. 108 mg/dL (95% CI 103-114) and metabolic acidosis (mean (95% CI) pH 7.29(95% CI 7.22-7.36) vs. 7.39 (95%CI 7.37-7.41)). CONCLUSIONS: In pediatric patients with COVID-19-related febrile seizures, the occurrence of seizures beyond the first day of fever, bradycardia, clustered seizures, status epilepticus, hyperglycemia, and metabolic acidosis should raise concerns about acute encephalitis/encephalopathy. However, the highest body temperature and the severity of leukocytosis or C-reactive protein levels were not associated with poor outcomes.
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Acidosis , Encefalopatías , COVID-19 , Hiperglucemia , Convulsiones Febriles , Estado Epiléptico , Niño , Humanos , Preescolar , Convulsiones Febriles/etiología , SARS-CoV-2 , Estudios Retrospectivos , Bradicardia/complicaciones , COVID-19/complicaciones , Fiebre/etiología , Encefalopatías/etiología , Convulsiones/complicaciones , Hiperglucemia/complicacionesRESUMEN
BACKGROUND: The clinical presentations of abusive head trauma can abruptly worsen, so the occurrence of seizures and changes of EEG can be variable according to patients' conditions. Since the changes of EEG background waves reflect the cortical function of children, we aimed to find out whether the timing of EEG background, epileptiform discharges and seizure patterns were associated with the outcomes of patients with AHT. MATERIAL AND METHODS: Using seizure type and acute stage electroencephalographic (EEG) characteristics to assess adverse neurological outcomes in children with seizures secondary to abusive head trauma (AHT). Children who were hospitalized with AHT at a tertiary referral hospital from October 2000 to April 2010 were evaluated retrospectively. A total of 50 children below 6 years of age admitted due to AHT were included. KOSCHI outcome scale was used to evaluate the primary outcome and neurological impairment was used as secondary outcome after 6 months discharge. RESULTS: Children with apnea, cardiac arrest, reverse blood flow and skull fracture in clinic had a higher mortality rate even in the no-seizure group (3/5 [60%] vs. 3/45 [6.7%], odds ratio [OR] = 11; 95% CI = 2.3-52; p = 0.025). Seizure occurrence reduced mostly at the second day after admission in seizure groups; but children with persistent seizures for 1 week showed poor neurological outcomes. The occurrence of initial seizure was frequency associated with younger age; focal seizure, diffuse cortical dysfunction in acute-stage EEG, and low Glasgow Coma Scale (GCS) score were significantly related to poor outcomes after 6 months. Diffuse cortical dysfunction was also associated with motor, speech, and cognitive dysfunction. CONCLUSIONS: Diffuse cortical dysfunction in acute-stage EEG combined with low GCS score and focal seizure may related to poor outcomes and neurological dysfunctions in children with AHT.
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PURPOSE: Our objective was to assess the adverse outcomes during pregnancy, as well as for the fetus and neonates, in women with epilepsy, both with and without the use of antiseizure medications (ASMs). METHODS: A cohort of singleton pregnancies between January 1, 2004 and December 31, 2014 was identified using the Taiwan National Health Database. The pregnancies were categorized into ASM exposure, ASM nonexposure, and control (consisting of women without an epilepsy diagnosis) groups. We recorded adverse outcomes in neonates and documented pregnancy complications. The generalized estimating equation with logit link was used to estimate adjusted odds ratios. RESULTS: There were 629 singleton pregnancies in the group exposed to ASMs, 771 in the epilepsy group without ASM exposure, and 2,004,479 in the control group. Women with epilepsy had a significantly higher risk of puerperal cerebrovascular diseases (adjusted odds ratios in the exposure and nonexposure groups = 54.46 and 20.37, respectively), respiratory distress syndrome (5.1 and 2.99), mortality (3.15 and 3.22), sepsis (2.67 and 2.54), pregnancy-related hypertension (1.71 and 1.8), preeclampsia (1.87 and 1.79), cesarean delivery (1.72 and 2.15), and preterm labor (1.38 and 1.56). The use of ASMs may increase the risk of eclampsia (adjusted odds ratio = 12.27). Compared to controls, fetuses/neonates born to women with epilepsy had a higher risk of unexplained stillbirth (adjusted odds ratios in the exposure and nonexposure groups = 2.51 and 2.37, respectively), congenital anomaly (1.37 and 1.33), central nervous system malformation (3.57 and 2.25), low birth weight (1.90 and 1.97), and a low Apgar score at 5 min (2.63 and 1.3). The use of ASMs may introduce an additional risk of small for gestational age; the adjusted odds ratio was 1.51. CONCLUSION: Women with epilepsy, irrespective of their exposure to ASMs, had a slightly elevated risk of pregnancy and perinatal complications. Puerperal cerebrovascular diseases may be a hidden risk for women with epilepsy.
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Trastornos Cerebrovasculares , Epilepsia , Complicaciones del Embarazo , Embarazo , Recién Nacido , Humanos , Femenino , Estudios de Cohortes , Epilepsia/tratamiento farmacológico , Epilepsia/epidemiología , Complicaciones del Embarazo/tratamiento farmacológico , Complicaciones del Embarazo/epidemiología , Recién Nacido Pequeño para la Edad GestacionalRESUMEN
OBJECTIVE: Bilateral frontoparietal polymicrogyria (BFPP) is a rare genetic-related migration disorder. It has been attributed to loss-of-function of the ADGRG1 gene, which encodes an adhesion G protein-coupled receptor, ADGRG1/GPR56. We report the EEG findings of BFPP in three Asian patients, and confirmed that change in protein function was caused by the novel missense variant (p.Leu290Pro). METHODS: We reviewed the medical records of three siblings with BFPP including one elder girl and two identical twin boys from birth to adulthood. The clinical symptoms, electroencephalography (EEG), brain MRI, whole-exome sequencing, treatment including medications, neuromodulation, and epilepsy surgery, and clinical outcomes were reviewed. The protein structure of a novel missense variant (p.Leu290Pro) was predicted by in silico studies, and molecular analysis was performed via typical flow cytometry and Western blotting. RESULTS: The elder girl (Patient 1) was 22 years old and the twin boys (Patients 2 and 3) were 20 years old at the time of publication. All of them presented with typical clinical symptoms/signs and MRI findings of BFPP. Whole-exome sequencing followed by Sanger confirmation showed that all three patients had compound heterozygous variants in the ADGRG1 gene. The missense variant (p.Leu290Pro) was confirmed to be related to a reduction in cell surface GPR56 expression. High-amplitude rhythmic activity was noted in sleep EEG during infancy, which may have been due to excessive sleep spindle, and the rhythm disappeared when they were of pre-school age. Partial callosotomy provided short-term benefits in seizure control in Patients 1 and 2, and combined vagus nerve stimulation and partial callosotomy provided longer benefits in Patient 3. SIGNIFICANCE: Sleep EEG findings of high-amplitude rhythmic activity in our BFPP cases were only noted during infancy and childhood. We also confirmed that the missense variant (p.Leu290Pro) led to loss of function due to a reduction in cell surface GPR56 expression.
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Polimicrogiria , Masculino , Femenino , Humanos , Lactante , Preescolar , Niño , Adulto Joven , Adulto , Hermanos , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Mutación MissenseRESUMEN
Repeat craniotomies to treat recurrent seizures may be difficult, and minimally invasive radiofrequency ablation is an alternative therapy. On the basis of this procedure, we aimed to develop a more reliable methodology which is helpful for institutions where real-time image monitoring or electrophysiologic guidance during ablation are not available. We used simulation combined with a robot-assisted radiofrequency ablation (S-RARFA) protocol to plan and execute brain epileptic tissue lesioning. Trajectories of electrodes were planned on the robot system, and time-dependent thermodynamics was simulated with radiofrequency parameters. Thermal gradient and margin were displayed on a computer to calculate ablation volume with a mathematic equation. Actual volume was measured on images after the ablation. This small series included one pediatric and two adult patients. The remnant hippocampus, corpus callosum, and irritative zone around arteriovenous malformation nidus were all treated with S-RARFA. The mean error percentage of the volume ablated between preoperative simulation and postoperative measurement was 2.4 ± 0.7%. No complications or newly developed neurologic deficits presented postoperatively, and the patients had little postoperative pain and short hospital stays. In this pilot study, we preliminarily verified the feasibility and safety of this novel protocol. As an alternative to traditional surgeries or real-time monitoring, S-RARFA served as successful seizure reoperation with high accuracy, minimal collateral damage, and good seizure control.
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PURPOSE: The incidence of Tourette syndrome and chronic tic disorders has seldom been evaluated in Asia. METHODS: Using the National Taiwan Insurance Research Database, the annual standardized incidence and prevalence of Tourette syndrome (TS) and chronic tic disorders were estimated from 2007 to 2015. The pre-existing comorbidity at disease diagnosis was also evaluated. RESULTS: From 2007 to 2015, the age- and sex-standardized incidence increased from 5.34 (95% confidence interval [CI] 5.06-5.62) per 100,000 person-years to 6.87 (95% CI 6.53-7.21) per 100,000 person-years. In children and adolescents, the age- and sex-standardized incidence increased from 19.58 (95% CI 18.42-20.75) per 100,000 person-years to 31.79 (95% CI 30.09-33.49) per 100,000 person-years. In adults, the age- and sex-standardized incidence decreased from 2.01 (95% CI 1.79-2.23) per 100,000 person-years to 1.24 (95% CI 1.07-1.42) per 100,000 person-years. The incidence rate ratio (IRR) between males and females was 3.74 (95% CI 3.32-4.22). The age- and sex-standardized prevalence increased from 37.51 (95% CI 36.75-38.27) per 100,000 people in 2007 to 84.18 (95% CI 83.02-85.35) per 100,000 people in 2015. The rate risk (RR) between males and females was 3.65 (95% CI 3.53-3.78). CONCLUSION: The annual incidence rates of TS and chronic tic disorders increased in childhood and adolescence but decreased in adulthood from 2007 to 2015. The prevalence rates increased over the same period.
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Trastornos de Tic , Síndrome de Tourette , Adolescente , Adulto , Niño , Femenino , Humanos , Incidencia , Masculino , Prevalencia , Taiwán/epidemiología , Trastornos de Tic/epidemiología , Síndrome de Tourette/epidemiologíaRESUMEN
Anti-glutamic acid decarboxylase (anti-GAD) antibodies are associated with different types of syndromes. However, few studies have investigated the correlation between anti-GAD antibody titers with clinical severity and outcomes in children with encephalitis/encephalopathy. In this single-center retrospective cohort study, we consecutively enrolled hospitalized children who had encephalitis and/or encephalopathy with positive anti-GAD antibodies in serum and/or cerebrospinal fluid (CSF) from February 2010 to October 2021. Thirty-seven patients were included and divided into high-titer and low-titer groups. The patients with high anti-GAD antibody titers were associated with initial symptoms of language difficulty and ataxia. The level of titers was not associated with severity or outcomes. Anti-GAD antibody titers decreased after immunotherapy, however, the clinical response to immunotherapy was variable. A transient elevation in anti-GAD antibody titers during immunotherapy was noted. Further studies are warranted to investigate the role of anti-GAD antibodies in the pathogenesis and immune mechanisms of encephalitis/encephalopathy.
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BACKGROUND: Patients with epilepsy have a higher mortality rate than the general population. Up-to-date estimates of epilepsy incidence, prevalence, and medication use are critical to assist policymaking. METHODS: Using the National Taiwan Insurance Research Database, the standardized incidence and prevalence of epilepsy were estimated in each calendar year from 2007 to 2015. We used the incident cases of epilepsy to analyze the change in prescribing patterns from 2007 to 2015. Joinpoint regression was used to estimate secular trends. RESULTS: From 2007 to 2015, the age- and sex-standardized incidence decreased from 0.72 (95% confidence interval [CI] 0.70-0.73) to 0.54 (95% CI 0.53-0.55) per 1,000 person-years, giving an annual percentage change (APC) of -2.73 (p < 0.05). Among patients younger than 20 years, the incidence did not change significantly. The age- and sex-standardized prevalence decreased from 6.94 (95% CI 6.90-6.98) to 6.86 (95% CI, 6.82-6.89) per 1,000 people, giving an APC of -0.31 (p < 0.05). However, the prevalence increased in the 35- to 49- and 50- to 64-year age-groups. The most common first-line anticonvulsant was phenytoin in 2007 and valproate in 2015. The use of levetiracetam, clobazam, and valproate increased during the study period, with APCs of 25.48% (95% CI 19.97-31.24), 6.41 (3.09-9.85), and 2.83 (1.51-4.16), respectively. The use of carbamazepine, phenytoin, and topiramate decreased; the APCs were -23.86% (95% CI -25.25 to -22.44), -6.61 (-8.40 to -4.79), and -4.29% (-7.87 to -0.57), respectively. CONCLUSIONS: The overall prevalence and incidence of epilepsy decreased slightly from 2007 to 2015. The prescribed first-line anticonvulsant also changed over time.
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Epilepsia , Epilepsia/tratamiento farmacológico , Epilepsia/epidemiología , Humanos , Incidencia , Levetiracetam/uso terapéutico , Prevalencia , Taiwán/epidemiologíaRESUMEN
BACKGROUND: Dravet syndrome is a severe developmental and epileptic encephalopathy characterized by the onset of prolonged febrile and afebrile seizures in infancy and SCN1A gene mutations. In some cases, non-SCN1A gene mutations can present with a phenotype very similar to that of Dravet syndrome. The aim of this study was to compare phenotypes of patients with SCN1A and non-SCN1A gene mutation-related Dravet syndrome. METHODS: Thirty-six patients with Dravet syndrome-like phenotypes were followed from July 2017 to December 2019. We retrospectively analyzed their clinical profiles and genetic surveys. RESULTS: Of the 36 enrolled patients, 15 (41.7%) had SCN1A mutations, one (2.8%) had an SCN8A mutation, one (2.8%) had an STX1B mutation, and five females (13.9%) had PCDH 19 mutations. The median age at first seizure onset was 7 months in those with SCN1A mutations, 1.3 years in those with PCDH19 mutations, and 10 months for the remaining patients. The majority of the patients with SCN1A mutations had status epilepticus (80% vs. 20%) and fever-sensitive seizures (76% vs. 31%) compared to those with PCDH19 mutations. The patients with SCN1A-related seizures had a higher rate of focal seizures as first seizure type than those without SCN1A mutations. Three of five (60%) patients with PCDH19 mutations had brain magnetic resonance imaging abnormalities. The three most commonly used antiseizure medications were sodium valproate, levetiracetam, and clobazam. Seven of the 15 patients with SCN1A mutations used stiripentol. The median time from seizure onset to genetic diagnosis was 6.6 years (range 4 months-22.3 years). CONCLUSION: The patients with SCN1A mutations in this study had high rates of fever-sensitive seizures, status epilepticus, seizure onset with focal seizure type, and relatively young age at seizure onset. The patients with PCDH19 mutations had a relatively high rate of abnormal brain magnetic resonance imaging findings.
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Epilepsias Mioclónicas , Canal de Sodio Activado por Voltaje NAV1.1 , Cadherinas/genética , Epilepsias Mioclónicas/diagnóstico , Epilepsias Mioclónicas/genética , Femenino , Humanos , Mutación , Canal de Sodio Activado por Voltaje NAV1.1/genética , Fenotipo , Protocadherinas , Estudios Retrospectivos , TaiwánRESUMEN
Acute encephalitis is an important pediatric emergency that tends to be associated with neurological morbidity, critical illness, and mortality. Few data have specifically focused on evaluating various early clinical parameters in the pediatric emergency department as candidate predictors of mortality. The present retrospective study assessed the clinical, laboratory, and neuroimaging findings of children with acute encephalitis who presented to the emergency department. Of 158 patients diagnosed with encephalitis, 7 (4.4%) had mortality. Compared to the survivors, a multivariate analysis revealed that an initial Glasgow Coma Scale score ≤ 5 (odds ratio [OR]: 8.3, P = .022), acute necrotizing encephalitis (OR: 12.1, P = .01), white blood count level ≤ 5.2 × 109 cells/L (OR: 28.7, P < .001), aspartate aminotransferase level > 35 U/L (OR: 14.3, P = .022), and influenza A infection (OR: 7.7, P = .027) were significantly associated with mortality. These results indicate that the early recognition of preliminary clinical features and the development of more specific etiologies for encephalitis are important for early treatment strategies.
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Servicio de Urgencia en Hospital , Encefalitis/mortalidad , Enfermedad Aguda , Encéfalo/diagnóstico por imagen , Niño , Electroencefalografía , Encefalitis/sangre , Encefalitis/diagnóstico por imagen , Femenino , Escala de Coma de Glasgow/estadística & datos numéricos , Humanos , Imagen por Resonancia Magnética , Masculino , Estudios Retrospectivos , Factores de Riesgo , Tomografía Computarizada por Rayos XRESUMEN
Objective: Valproic acid is the most high-risk teratogenic antiepileptic drug, and it may lead to fetal major congenital malformations. However, it is still used in women of childbearing age with epilepsy. The aim of this study was to report our experience of discontinuing or lowering valproic acid by adding levetiracetam, a low-risk teratogenic antiepileptic drug. Methods: We reviewed the medical records of childbearing age female patients with epilepsy who were treated with valproic acid initially and then switched to levetiracetam. The clinical profiles were recorded. The primary outcome was successful switching, which was defined as a decrease in the daily valproic acid dosage, after levetiracetam had been added. Results: Twenty-four female patients were enrolled (median age 22 years). The successful switching rate was 83.3% (20/24), and 55% (11/20) discontinued valproic acid after levetiracetam had been added. There were no significant differences between the successful and unsuccessful groups in etiology, electroencephalogram, and magnetic resonance imaging findings. Pharmacoresistant to levetiracetam was much higher in the unsuccessful group (45 vs. 100%). The median switching duration was 19.5 months in the successful group. There were improvements in metrorrhagia and alopecia in all of the patients in the successful group after valproic acid had been tapered. Conclusions: Our experience supports switching valproic acid to levetiracetam in childbearing age women with epilepsy as an effective strategy to lower the teratogenic rate and adverse effects. A long switching period was noted in this study. We suggest starting early in childbearing age women with epilepsy.
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BACKGROUND: Few studies have examined the effects of the Child Protection Act on child maltreatment in Taiwan. OBJECTIVE: This study estimated the secular trends in the incidence rate of physical abuse of children requiring hospitalization between 1996 and 2013, and the subsequent in-hospital death proportion before and after implementation of the Act in 2003. PARTICIPANTS AND SETTING: The cases were children younger than 12 years old who were hospitalized due to child abuse, shaken-baby syndrome, neglect, or homicide between 1996 and 2013. A comparison group consisted of children requiring hospitalization for other reasons. We used the National Health Insurance database to identify patients. METHODS: The Joinpoint Regression Program was used to estimate temporal trends in the standardized incidence rates. RESULTS: Between 1996 and 2013, 2050 children required hospitalization for physical abuse. Before 2005, the annual percent change increased by 9.40 [95% confidence interval (CI), 4.98-14.00] per year, and after 2005 the annual percent change was -4.80 (95% CI, -9.53-0.17) per year. Among the 2050 physically abused children requiring hospitalization, 83 (4%) died in hospital. The in-hospital death proportion was 2.62% before 2003 and 4.90% after 2003, and the ratio of these two proportions was 1.43 (95% CI, 0.80-2.58). CONCLUSIONS: The trend in the incidence of hospitalization of children due to physical-abuse-related injuries started to decline 2 years after implementation of the Child Protection Act. However, the proportion of children who died in hospital as a result of physical abuse requiring hospitalization did not change.
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Maltrato a los Niños/tendencias , Homicidio/tendencias , Mortalidad Hospitalaria/tendencias , Hospitalización/tendencias , Síndrome del Bebé Sacudido/epidemiología , Adolescente , Niño , Maltrato a los Niños/legislación & jurisprudencia , Maltrato a los Niños/prevención & control , Preescolar , Bases de Datos Factuales , Femenino , Hospitalización/estadística & datos numéricos , Humanos , Incidencia , Lactante , Masculino , Síndrome del Bebé Sacudido/prevención & control , Taiwán/epidemiologíaRESUMEN
BACKGROUND: Myasthenia gravis is the most common disease affecting the neuromuscular junction. The most common etiology among patients with juvenile myasthenia gravis is the production of antibodies against the acetylcholine receptor. However, the clinical outcome in relation to serum levels of anti-acetylcholine receptor antibodies in juvenile myasthenia gravis has rarely been discussed. We aimed to analyze the correlation between the presence of anti-acetylcholine receptor antibodies and outcome in juvenile myasthenia gravis. METHODS: Patients diagnosed with juvenile myasthenia gravis younger than of 20 years of age were retrospectively recruited from January 1995 to February 2017 in a tertiary referral medical center. According to the Myasthenia Gravis Foundation of America outcome scale, the primary outcome was complete symptom remission and cessation of medications for at least 1 year measured 2 years after diagnosis. Secondary outcome was complete symptom remission at the last outpatient clinic. RESULTS: A total of 54 patients were followed up for over 2 years. Nine patients (9/54, 16.7%) achieved complete remission without medication use at 2 years after diagnosis. Thirteen (24.1%) patients achieved complete remission during longer follow-up periods. Those with negative anti-acetylcholine receptor antibodies were more likely to achieve complete remission at 2 years (6/15 [40%] vs. 3/39 [7.7%], 95% Confidence interval [CI] 1.670 to 38.323) and at the last outpatient clinic follow-up (8/15 [53.3%] vs. 5/39 [12.8%], 95% CI 2.367 to 20.704). Thirteen patients with comorbid autoimmune thyroid diseases were older than those without disease (11.8 ± 5.8 years old vs. 8.0 ± 6.3 years old, 95% CI 0.018 to 7.33). Moreover, patients negative for anti-acetylcholine receptor antibodies were less likely comorbid with autoimmune thyroid disease (1/35 [2.9%] vs. 12/71 [16.9%], 95% CI 0.018 to 1.161). CONCLUSIONS: Juvenile myasthenia gravis patients without anti-acetylcholine antibodies exhibited significantly increased complete remission rates and a reduced likelihood of comorbid autoimmune thyroid diseases compared with those with anti-acetylcholine receptor antibodies among Chinese.
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Miastenia Gravis/inmunología , Receptores Colinérgicos/inmunología , Acetilcolina , Adolescente , Autoanticuerpos/sangre , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Enfermedad de Hashimoto/complicaciones , Humanos , Lactante , Masculino , Miastenia Gravis/sangre , Miastenia Gravis/epidemiología , Unión Neuromuscular , Inducción de Remisión , Estudios Retrospectivos , Taiwán/epidemiología , Adulto JovenRESUMEN
BACKGROUND: Nitrous oxide (N2O) is a commonly used inhaled anesthetic in outpatient dental procedures. However, the increasing recreational use of N2O may result in vitamin B12 deficiency-related neurologic and psychiatric symptoms. The aim of this study was to demonstrate the clinical features of chronic N2O abuse in pediatric patients. METHODS: Patients under 20â¯years of age who were diagnosed with N2O-induced subacute combined degeneration of the spinal cord from 2012 to 2018 were enrolled in this study. Clinical presentations, laboratory, imaging, ancillary studies, treatments and outcomes were analyzed. RESULTS: Nine patients were included, all of whom presented with symptoms of myeloneuropathy including limb numbness, limb weakness or unsteady gait. Six patients had low or low-normal vitamin B12 (cyanocobalamin) levels. Eight patients had evidence of subacute combined degeneration of the spinal cord via neuroimaging studies. All of the patients received vitamin B12 supplementation as treatment. All had full recovery of muscle power within 2â¯months. Five patients had persistent sensory deficits. CONCLUSION: Chronic N2O abuse can cause permanent neurological damage if not treated promptly. Clinical staff should be aware of the various presentations of neurotoxicity related to N2O abuse.