Mandatory electrocardiographic monitoring in young patients treated with psychoactive drugs

Abstract

The pharmacotherapy for the management of tic and obsessive–compulsive disorder in Tourette syndrome relies on neuroleptics and selective serotonin reuptake inhibitors, which have been associated with electrocardiographic abnormalities, including QTc interval prolongation and increased risk of sudden cardiac death (SCD) in patients taking these drugs. Congenital long QT syndrome (LQTS) is an inherited condition characterized by a prolonged QT interval, and consequently is a major risk factor for torsades de pointes and SCD. We reported a case of critical QTc prolongation due to pimozide and fluoxetine therapies in a 10-year-old boy with Tourette syndrome and obsessive–compulsive disorder and unknown QT long syndrome. The patient’s family history was not contributory; no family member had a history of sudden death, syncope, or congenital heart disease. Pregnancy and developmental milestones during infancy were normal. At the age of 6 years, he began to present motor tics. A few years later, he started to present obsessions and compulsions, and for this reason, he was referred to us for our expert opinion. Both general and neurological examinations were normal. Mental state examination showed an intact cognitive state. During the visit, we observed the following motor and phonic tics: eye blinking, nose movements, lip licking, finger movements, echolalia, and echopraxia. Neuropsychological evaluation gave the following results: Yale Global Tic Severity Scale (YGTSS) 30; YaleBrown Obsessive Compulsive Scale (Y-BOCS) 38; Diagnostic Confidence Index, 80 %. Routine investigations to date have been normal, including brain magnetic resonance imaging and surface ECG (QTc: 418 ms). We prescribed pimozide at a dosage of 4 mg/day with marked improvement either in tics or in obsessions–compulsions. His global severity score on the YGTSS dropped to 22, and his global severity score on the Y-BOCS dropped to 28. After 3-month follow-up, the patient underwent a repeat routine investigation and surface ECG that showed an increase of QTc length (478 ms). We stopped pimozide, and in 15 days, the QTc was within the normal range (418 ms). Without any pharmacological treatment, his symptoms worsened concerning either tics or obsession– compulsion. His YGTSS was 22 and Y-BOCS was 36. We then prescribed fluoxetine at the dosage of 20 mg/ day, and after 3-month follow-up, he showed an improvement in symptoms; his scores in the neuropsychological scales were as follows: YGTSS 18; Y-BOCS 28. We repeated surface ECG which again showed an increase of QTc length (471 ms). We stopped the treatment and repeated the ECG, which then showed QTc length normalization after 15 days and worsening of Tourette symptoms. During the drug administration, the boy never presented with syncope or orthostatic hypotension. R. Rizzo (&) M. Gulisano P. V. Cali Section of Child Neuropsychiatry, Dipartimento di Scienze Mediche e Pediatriche, Catania University, Via Santa Sofia 78, 95123 Catania, Italy e-mail: rerizzo@unict.it