A 4-year-old boy is brought in by his grandmother for worsening seizure activity. She reports that occasionally he “suddenly drops” when running around the house. She says that his first seizure occurred 1 year ago. Since then, he has been on valproic acid but the seizure activity remains unchanged. He was recently enrolled in daycare because she could no longer care for him full-time. Since then, the seizure activity has increased and the daycare facility also noted concerns over his lack of response to voice commands. Family history is significant for a cousin who died suddenly at a young age. His temperature is 98.6°F (37°C), blood pressure is 105/52 mmHg, pulse is 110/min, and respirations are 25/min. A physical exam is significant for lack of response to auditory stimulation. An EEG is performed, which is unrevealing. An ECG is shown in Figure A. The patient is then startled when a door is closed quickly and he suddenly loses consciousness. An ECG is quickly performed and is shown in Figure B. An electrolyte panel is drawn with the following findings:

Serum:
Na+: 142 mEq/L
Cl-: 88 mEq/dL
K+: 3.4 mEq/L
HCO3-: 24 mEq/L
BUN: 11 mg/dL
Glucose: 67 mg/dL
Creatinine: 0.6 mg/dL
Mg2+: 1.7 mg/dL

Which of the following is the most appropriate next step in management?
Implant a pacemaker
Replete potassium and magnesium and start a beta-blocker
Start ethosuximide
Administer intravenous lorazepam
Replete potassium and magnesium and start a beta-blocker
The patient who presents with deafness and long QT syndrome that progressed to torsades de pointes most likely has Jervell and Lange-Nielsen syndrome. The most appropriate next step in management is to replete potassium and magnesium and then start a beta-blocker.

Jervell and Lange-Nielsen syndrome is an autosomal recessive disorder caused by defective potassium ion channels. This causes abnormal function of the inner ear resulting in congenital sensorineural deafness as well as abnormal myocardial conduction resulting in long QT syndrome. A prolonged QT interval increases the risk of ventricular dysrhythmias, especially torsades de pointes, which may manifest as syncope, or sudden death. These episodes are usually triggered by exertion or by being startled. Management of symptomatic congenital long QT syndromes or torsades de pointes should involve the repletion of potassium and magnesium as well as the initiation of a beta-blocker medication. If symptoms are refractory to beta-blockers, a pacemaker can be implanted to avoid cardiac arrest.

Adam et al. review the evidence regarding the diagnosis and treatment of Jervell and Lange-Nielsen syndrome. They discuss how a beta blocker medication should be used for medical control of this syndrome. They recommend pacemaker placement in refractory cases.

Figure/Illustration A is an ECG showing a prolonged QT interval (blue lines). This interval can be prolonged due to certain medications such as ondansetron or it can be due to long QT syndrome, which may be acquired or congenital.

Figure/Illustration B is an EKG showing a polymorphic ventricular tachycardia with varying QRS complex amplitudes over time (blue curve). This feature where the QRS complexes appear to “twist” around the isoelectric line is seen in torsades de pointes.

Incorrect Answers:
Answer A: IV lorazepam is the medical treatment for pediatric status epilepticus. Status epilepticus is a seizure that lasts for greater than 5 minutes or recurrent seizures with no return to baseline. This patient has an ECG showing torsades de pointes, which explains his sudden loss of consciousness as well as a normal EEG.

Answer B: A pacemaker can be used to treat refractory dysrhythmias caused by Jervell and Lange-Nielsen syndrome, but would not be the initial step in management for this patient. Beta-blocker medications should be used prior to pacemaker placement.

Answer D: While potassium and magnesium should be repleted, procainamide is a class 1A anti-arrhythmic medication that prolongs the QT interval. This class of medication is contraindicated in patients with long QT syndrome or torsades de pointes.

Answer E: Ethosuximide is used to treat absence seizures. The loss of consciousness associated with Jervell and Lange-Nielsen syndrome can be mistaken for absence seizures, but the patient's prolonged QT interval on ECG makes Jervell and Lange-Nielsen syndrome the most likely diagnosis. Of note, valproic acid is also a medication for absence seizures.

Bullet Summary:
Jervell and Lange-Nielsen syndrome should be treated with repletion of potassium and magnesium as well as initiation of beta-blocker medication with pacemaker placement reserved for refractory cases.