Paroxysmal non-kinesigenic dyskinesia, post-streptococcal syndromes and psychogenic movement disorders: a diagnostic challenge

We report a case of a 15-year-old boy presenting with sudden attacks of hyperkinetic movements of the limbs, trunk and neck. Clinical features were suggestive of paroxysmal non-kinesigenic dyskinesia, but the elevated antistreptolysin O antibody titre and history of recurrent upper airways infection led us to consider a post-streptococcal syndrome as a possible diagnosis. The patient started therapy with benzathine penicillin, sodium valproate and clonazepam without any significant improvement. A successive psychiatric assessment revealed the presence of a psychogenic movement disorder. Psychodynamic psychotherapy and individual counselling were started with progressive improvement of psychological symptoms and gradual resolution of hyperkinetic episodes, without any recurrence recorded during the follow-up (10 months).