Long QT syndrome with potassium voltage-gated channel subfamily H member 2 gene mutation mimicking refractory epilepsy: case report

Abstract

Background Epileptic seizures can be difficult to distinguish from other etiologies that cause cerebral hypoxia, especially cardiac diseases. Long QT syndrome (LQTS), especially LQTS type 2 (LQT2), frequently masquerades as seizures because of the transient cerebral hypoxia caused by ventricular arrhythmia. The high rate of sudden death in LQTS highlights the importance of accurate and early diagnosis; correct diagnosis of LQTS also prevents inappropriate treatment with anti-epileptic drugs (AEDs). Case presentation We report a case of congenital LQT2 with potassium voltage-gated channel subfamily H member 2 gene (KCNH2) mutation misdiagnosed as refractory epilepsy and treated with various AEDs for 22 years. The possibility of cardiac arrhythmia was suspected after the patient presented to the emergency room and the electrocardiograph (ECG) monitor showed paroxysmal ventricular tachycardia during attacks. Atypical seizure like attacks with prodromal uncomfortable chest sensation and palpitation, triggered by auditory stimulation, and typical ventricular tachycardia monitored by ECG raised suspicion for LQT2, which was confirmed by exome sequencing and epileptic seizure was ruled out by 24-h EEG monitoring. Although the patient rejected implantation of an implantable cardioverter defibrillator, β blocker was given and the syncope only attacked 1–2 per year when there was an incentive during the 5 years follow up. Conclusions Our case illustrates how long LQTS can masquerade convincingly as epilepsy and can be treated wrongly with AEDs, putting the patient at high risk of sudden cardiac death. Careful ECG evaluation is recommend for both patients with first seizure and those with refractory epilepsy.

KCNH2 variants in a family with epilepsy and long QT syndrome: A case report and literature review

“…As shown in Table 2, two studies reported sudden death among affected people, indicating that the gene variant has a high associated risk. 7,13,15,16,[18][19][20][21][22][23][24][25][26][27][28][29] Here, we report a family with a KCNH2 Arg 744* pathogenic variant presenting with both epilepsy and LQTS. The same variant was previously reported in patients with epilepsy or LQTS, but none of these cases had a dual phenotype of epilepsy and LQTS.…”

“…Although the KCNH2 Arg 744* variant has been previously reported in patients with epilepsy or LQTS, none of these cases had a dual phenotype of epilepsy and LQTS (Table 2). As shown in Table 2, two studies reported sudden death among affected people, indicating that the gene variant has a high associated risk [7,13,15,16,[18][19][20][21][22][23][24][25][26][27][28][29].…”

Shades of a channelopathy—Hypoperfusion, excitability, or both: A case video

“…LQTS characteristically manifests with an EKG finding of torsades de pointes and presents with syncope or sudden cardiac death. It frequently masquerades as epilepsy in its presentation, and sudden death from LQTS also mimics sudden unexpected death in epilepsy (SUDEP) 3–5 . Apart from cardiac tissues, the ion channels of LQT are also identified in non‐cardiac tissues 2 …”

“…It frequently masquerades as epilepsy in its presentation, and sudden death from LQTS also mimics sudden unexpected death in epilepsy (SUDEP). [3][4][5] Apart from cardiac tissues, the ion channels of LQT are also identified in non-cardiac tissues. 2 We report a case of a 33-year-old female who presented to the epilepsy clinic with a history of recurrent episodes…”

Atenolol reduces cardiac-mediated mortality in genetic mouse model of sudden unexpected death in epilepsy

“…In the brain, Kv11.1 regulates neuronal excitability and has been associated with seizure and epilepsy 27–31 . However, as patients with LQTS often experience syncope accompanied by a non-epileptic seizure, they are frequently misdiagnosed with epilepsy and incorrectly treated with anti-seizure medications 28,32,33 .…”