Aim  The purpose of this study was to report a prospective cohort of children with acute-onset movement disorders.

Method  We report on 52 individuals (31 females, 21 males; mean age 6y 5mo, range 2mo–15y) with acute-onset movement disorders managed at a busy tertiary paediatric referral hospital over a 40-month period.

Results  In descending order of frequency, the movement disorders reported were chorea, dystonia, tremor, myoclonus, and parkinsonism. It was possible to divide the participants into three groups: (1) those with inflammatory or autoimmune disorders (n=22), (2) those with non-inflammatory disorders (n=18), and (3) those with psychogenic disorders (n=12). The inflammatory or autoimmune aetiologies included N-methyl-d-aspartate receptor encephalitis (n=5), opsoclonus–myoclonus syndrome (n=4), Sydenham chorea (n=3), systemic lupus erythematosus (n=3), acute necrotizing encephalopathy (n=3), and other types of encephalitis (n=4). Other important non-inflammatory movement disorder aetiologies included drug-induced movement disorder (n=6), post-pump chorea (n=5), metabolic (n=3) and vascular (n=2) disease. The participants with psychogenic movement disorders (n=12) were all over 10 years of age and were more likely to be female. Tremor and myoclonus were significantly over-represented in the psychogenic movement disorder subgroup. The outcomes of the total cohort were variable, and included full recovery, severe morbidity, and death.

Interpretation  Acute-onset movement disorders in children are important and may be treatable. Management should focus upon identifying the cause and treating the underlying disease process, as symptomatic treatment of the abnormal movements is variably effective.