Psychogenic Movement Disorder After H1N1 Influenza Vaccination

This straight-A second-grade elementary school student was admitted for abrupt-onset seizure-like movements. She presented with uncontrolled bilateral hand movements 1 day after the first dose of H1N1 vaccination at school (non-adjuvanted H1N1v vaccine, AdimFlu-S (A/H1N1) Adimmune Corp., Taichung, Taiwan; 0.5 ml, IM injection). The intermittent hand movements persisted and progressed to lower limbs in the next 2 weeks. Both horizontal and vertical movements of bilateral legs were noted, which were dysrhythmic and incongruent with a classical organic movement disorder. Her consciousness remained clear, and she could communicate with her family throughout the course. The duration of each episode was variable, and it sometimes persisted for more than 1 hour. She was hospitalized for evaluation of suspected status epilepticus, and her abnormal movements were partially relieved by diazepam or dormicrium. Complete blood counts, biochemistry, CSF study, infectious-pathogen studies, and awake electroencephalography were unremarkable. Psychogenic illness was highly suspected when her movements subsided after suggestion and placebo injection with normal saline. Further stressors were identified, including high scholarship expectation of her parents and bullying at school. The diagnosis of psychogenic movement disorder was established, and psychotherapy was given. Occasional abnormal limb movements were noted after discharge but did not disturb her daily life.

Pandemic infectious disease can lead to psychogenic illness, for example, somatic symptoms and anxiety. The first patient with H1N1v infection in Taiwan was identified on May 20, 2009, and anxiety spread in the general public soon. A universal-vaccination program was carried out to control the pandemic. The systemic reaction after H1N1v vaccination is around 53.8%, and symptoms are mild and self-limiting.² However, doubt and distrust regarding the safety and efficacy of vaccination developed in the public, and the possible adverse effects were amplified and overemphasized, regardless the substantive relationship with vaccination. Public psychogenic illness after vaccination is reported as “mass psychogenic illness” or “psychogenic hysteria.”³ The etiology is not clear, but it is not regarded as the result of vaccination itself. The mass media plays an important role in disseminating and sensationalizing vaccine objections, although some information is incorrect or unconfirmed.⁴ Children are more susceptible to group anxiety, and the atmosphere in the place vaccinated enhances the fear and anxiety. Many school children cry before intramuscular injection, and they feel dizzy and weak along with their classmates.

Psychogenic movement disorder remains a diagnostic challenge to physicians, and most are diagnosed after age 10.⁵ The diagnosis of psychogenic movement disorder is difficult, and the prevalence is about 3.1% in pediatric movement-disorder populations.¹ Anticipating stressors, secondary gain, and malingering are frequently noted in patients with psychogenic movement disorder, and precipitants are common, such as trauma or major emotionally stressful life events. Our patient is relatively younger, and psychogenic movement disorder after vaccination has rarely been reported previously.

In conclusion, the emerging importance of psychiatric disorder in children raises our attention. In facing the pandemic infection, psychogenic stress should be concerned and the idea that a universal vaccination program may result in mass psychogenic illness. Psychogenic movement disorder is easily neglected in children, and it may be precipitated by influenza vaccination.

C.Y. Lin involved in writing the first draft, patient assessment, and follow-up. C.C. Peng was involved in patient assessment and intensive care. H.C. Liu was involved in psychiatric evaluation and psychotherapy. N.C. Chiu was involved in review and critique, patient assessment, and follow-up.