Long QT syndrome presenting as epileptic seizures in an adult

Hunt, Derek Jc; Tang, Kai Lun

doi:10.1136/emj.2003.007997

Cited by 33 publications

(22 citation statements)

References 5 publications

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“…Because seizure is one of the typical symptoms of LQT2, LQT2 is easily misdiagnosed as epilepsy. Many patients with recurrent convulsions who were treated for epilepsy for years were finally diagnosed with LQT (Gatto et al, 1993;Scheepers et al, 1998;Medina-Villanueva et al, 2002;Hunt and Tang, 2005;Johnson et al, 2009;MacCormick et al, 2009;Jorge et al, 2011). Although the responsible genes of the two channelopathies are different, besides misdiagnosis, increasing evidence argues for a close pathogenic relationship between LQT2 and epilepsy (Johnson et al, 2009;Keller et al, 2009;MacCormick et al, 2009;Omichi et al, 2010;Zamorano-Leon et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

The Human Ether-A-Go-Go–Related Gene Activator NS1643 Enhances Epilepsy-Associated KCNQ Channels

Chen

Zhang

et al. 2014

J Pharmacol Exp Ther

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Human ether-a-go-go-related gene (hERG) and KCNQ channels are two classes of voltage-gated potassium channels. Specific mutations have been identified that are causal for type II long QT (LQT2) syndrome, neonatal epilepsy, and benign familial neonatal convulsions. Increasing evidence from clinical studies suggests that LQT2 and epilepsy coexist in some patients. Therefore, an integral approach to investigating and treating the two diseases is likely more effective. In the current study, we found that NS1643 [1,3-bis-(2-hydroxy-5-trifluoromethyl-phenyl)-urea], a previously reported hERG activator, is also an activator of KCNQ channels. It potentiates the neuronal KCNQ2, KCNQ4, and KCNQ2/Q3 channels, but not the cardiac KCNQ1. The effects of NS1643 on the KCNQ2 channel include left shifting of voltage for reaching 50% of the maximum conductance and slowing of deactivation. Analysis of the dose-response curve of NS1643 revealed an EC 50 value of 2.44 6 0.25 mM. A hydrophobic phenylalanine (F137) located at the middle region of the voltage-sensing domain was identified as critical for NS1643 activity on KCNQ2. When testing NS1643 effects in rescuing LQT2 hERG mutants and the KCNQ2 BFNC mutants, we found it is particularly efficacious in some cases. Considering the substantial relationship between LQT2 and epilepsy, these findings reveal that NS1643 is a useful compound to elucidate the causal connection of LQT2 and epilepsy. More generally, this may provide a strategy in the development of therapeutics for LQT2 and epilepsy.

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Section: Discussionmentioning

confidence: 99%

The Human Ether-A-Go-Go–Related Gene Activator NS1643 Enhances Epilepsy-Associated KCNQ Channels

Chen

Zhang

et al. 2014

J Pharmacol Exp Ther

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“…Self-terminating episodes of TdP are reported to cause hypotension and seizures, probably due to cerebral hypoperfusion [16] and may be suggested as a reason for the incident that made the patient admitted to hospital.…”

Section: Discussionmentioning

confidence: 99%

Survival after prolonged resuscitation with 99 defibrillations due to Torsade De Pointes cardiac electrical storm: a case report

Nakstad

Eek

Aarhus

et al. 2010

Scand J Trauma Resusc Emerg Med

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A 48-year-old previously healthy woman suffered witnessed cardiac arrest in hospital. She achieved return of spontaneous circulation and was transferred to the intensive care unit. During the following 3 hours, she suffered a cardiac electrical storm with 98 episodes of Torsade de Pointes ventricular tachycardia rapidly degenerating to ventricular fibrillation. She was converted with a total of 99 defibrillations. There was no response to the use of any recommended anti arrhythmic drugs. However, the use of bretylium surprisingly stabilized her heart rhythm and facilitated placing of a temporary pacemaker. Overdrive pacing prevented further arrhythmias and was life saving. A number of beneficial factors may have contributed to the good neurological outcome. Further investigations gave no explanation for her cardiac electrical storm.

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“…In the present case, the patient's QTc interval was 623 ms (163 ms higher than baseline). In rare instances, cardiac disease such as long QT syndrome induced TdP can present as seizure [2,3]. Table 1: QTc prolongation into 3 gender-specific groups: normal; borderline; and abnormal.…”

Section: Discussionmentioning

confidence: 99%

Differential Diagnosis of Transient Left Ventricular Dysfunction in a Critically Ill Patient

Jayaraj¹,

Ganesan²

2018

J Clin Exp Cardiolog

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There is evidence illustrating that the etiologies of non-ischemic LV (left ventricular) dysfunction such as Takotsubo cardiomyopathy, neurogenic stunning myocardium and post resuscitation stunning myocardium have a favorable clinical outcome. Good prognosis in non-ischemic LV dysfunction provides us courage to treat the condition expecting good. We describe herein the unique case of a 33-year-old woman who was started on combination chemotherapy of oxaliplatin and 5-flurouracil for colon adenocarcinoma. The patient's baseline QTc was 460 ms. Twenty-four hours following initiation of chemotherapy, the patient developed 3 discrete episodes of tonicclonic seizures. Electrocardiogram assessment demonstrated a prolonged QTc interval (623 ms) with several episodes of TdP. Two episodes required defibrillation to revert to sinus rhythm. Post resuscitation echocardiogram showed severe global LV dysfunction with ejection fraction of 33%. The patient subsequently required mechanical ventilation due to severe LV dysfunction with pulmonary edema. Possible etiologies for LV dysfunction in the present case include global Takotsubo cardiomyopathy, neurogenic stunning myocardium or post resuscitation stunning myocardium. Repeat echocardiogram 48 h later showed the ejection fraction of 60%. Although myocardial dysfunction associated with Takotsubo cardiomyopathy, neurogenic stunning myocardium and post resuscitation stunning myocardium have been previously described independently, the present case is unique in that, to our knowledge, torsade de pointes presented with transient left ventricular dysfunction following several episodes of seizures and post resuscitation stunning myocardium that were stabilized in one patient following oxaliplatin and 5-fluorouracil infusion has not been reported. Case ReportA 33-year-old female patient who underwent hemicolectomy for colon adenocarcinoma was admitted for chemotherapy. Her past medical history was unremarkable and notably, not significant for cardiovascular, respiratory or neurological disorders. She did not have intracranial metastasis. The patient was not on any medications that could affect the QT interval. Baseline blood investigations including electrolytes and renal parameters were within normal limits. The physical examination was unremarkable. Baseline electrocardiogram demonstrated normal sinus rhythm, normal PR interval and the Bazett-corrected QT interval was 460 ms. Echocardiogram showed normal size cardiac chambers, no regional wall motion abnormality and good LV systolic function, with ejection fraction of 67%.Chemotherapy regimen was modified Folfox consisting of oxaliplatin 85 mg/m 2 intravenous on Day 1, 5-FU 400 mg/m 2 intravenous bolus on Day 1, followed by continuous infusion 1500 mg/m 2 for 22 h on Day 1 and 2. Leucovorin (folinic acid) 75 mg/m 2 was given as continuous infusion on Day 1 and 2.Twenty-four hours after initiation of chemotherapy, the patient developed a seizure that was initially treated with intravenous diphenylhydantoin in the ward. Withi...

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Long QT syndrome presenting as epileptic seizures in an adult

Cited by 33 publications

References 5 publications

The Human Ether-A-Go-Go–Related Gene Activator NS1643 Enhances Epilepsy-Associated KCNQ Channels

The Human Ether-A-Go-Go–Related Gene Activator NS1643 Enhances Epilepsy-Associated KCNQ Channels

Survival after prolonged resuscitation with 99 defibrillations due to Torsade De Pointes cardiac electrical storm: a case report

Differential Diagnosis of Transient Left Ventricular Dysfunction in a Critically Ill Patient

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