Atomoxetine Use in Attention-Deficit/Hyperactivity Disorder and Comorbid Tic Disorder in Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections

Introduction

Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) have five criteria: presence of obsessive compulsive disorder (OCD) and/or tic disorder (TD), prepubertal symptom onset, sudden onset or episodic course of symptoms, temporal association between streptococcal infections and neuropsychiatric symptom exacerbations, and associated neurological abnormalities (Swedo et al.1998; Chang et al. 2015). The diagnosis of PANDAS is complicated, and PANDAS have a variety of comorbid psychiatric conditions. Distinguishing PANDAS from other disorders such as OCD, tic, or other movement disorders and implementation of a treatment protocol are difficult (Murphy et al. 2012). Sudden onset OCD and tics are mostly encountered psychiatric clinical features. Antibiotics, plasmapheresis, intravenous immunoglobulins, and treatment of specific psychiatric conditions are approved clinical treatment options. Recent studies have shown that psychiatric symptoms observed in PANDAS may respond less to conventional psychotrophic drugs than the those in pure psychiatric conditions. Attention-deficit/hyperactivity disorder (ADHD) is seen in 40% of the PANDAS cases (Swedo et al. 2012). Atomoxetine has a selective noradrenaline reuptake inhibitor activity used for ADHD. It is somehow known as having less impact on tic exacerbations than psychostimulants (Allen et al. 2005). Here we report two cases with ADHD and PANDAS who were treated with atomoxetine for their ADHD and comorbid tics.

Case Reports

Discussion

Atomoxetine use in PANDAS has not been reported before up to our knowledge. Here in these cases, we used atomoxetine for ADHD comorbid with TD. Atomoxetine is known to have limited effects on tic exacerbations, besides it may have positive effects on tics (Allen et al. 2005). The neurobiological factors responsible for tics are heterogeneous, which are the abnormalities in multiple corticostriatal circuits and disordered neurotransmissions including mostly dopaminergic, but as well as serotonergic, noradrenergic, histaminergic, and amino acid (GABA and glutamate) systems (Leckman et al. 2010). That is why atomoxetine use reduced tics in our first case. The severity of ADHD symptoms was decreased by atomoxetine in our cases. Our first case, whose TD was of acute type, was also successfully treated with atomoxetine; in contrast, our second case, who had a chronic disease feature, showed little improvement in tics. Therefore, additional drug, aripiprazole, was added for tic control (Yang et al. 2015). Also, drug metabolisms may differ according to age and gender, leading to different effects observed in our cases. Diagnosis of PANDAS and other novel forms of pediatric acute-onset neuropsychiatric disorders (PANS) and childhood acute-onset neuropsychiatric disorders (CANS) deserves careful examination and laboratory testing and needs a multidisciplinary approach; however, no specific treatment guideline has been established so far (Swedo et al. 2012, Chang et al. 2015). As a result, our experiences showed that atomoxetine may be an effective treatment in ADHD comorbid with PANDAS, particularly during the acute disease period.