Paroxysmal exercise-induced dyskinesia diagnosed using exercise test

Abstract

Background Paroxysmal movement disorders are interesting forms of hyperkinetic movement disorders
that are perplexing to the neurologist and patients. The main features are transient dystonia or chorea
involving various body parts and lasting few seconds, minutes or hours depending on the subtype. The
paroxysmal exercise-induced dyskinesia is associated with a gene mutation of (NM_145239.2:c.649dupC)
in proline-rich trans-membrane protein 2 (PRRT2). This is found in an average of 45% of cases. Familial
cases have 85% penetrance.
Case report We report a case of a 12-year old boy with intermittent episodes of abnormal movements
which involved his face and / or limbs. These dyskinesias occur every few days without warning.
Complete neurological examination was normal. Importantly, Magnetic Resonance Imaging head and
Electroencephalography were normal in association with normal haemto-biochemistry profile. The family
recorded a video for one episode of his abnormal movement. The doctor set a challenge of 20 meters racing.
He excited the patient then started the race with the attendance of the parents and the nurse. Few seconds
after the end of the race the development of the abnormal movement was judged by the parents and nurse
who all agreed on the provocation test.
Conclusion Paroxysmal exercise-induced dyskinesia is the commonest primary episodic movement
disorder which has its negative effect on the quality of life. The diagnosis and management are mainly
clinical. It is of paramount importance to use simple tests (exercise test) and save the patient unnecessary
worries and side effects of medications.