Introduction:

Paroxysmal dyskinesia in children are of three types 1.PKD  2.PNKD 3.PED Most of them are channelopathies. We hereby report two siblings who presented with isolated PED as a manifestation of pyruvate dehydrogenase deficiency.

Case Vignette:

A 7yr old boy born to non-consanguineous parents presented with history of dystonia of both lowerlimb on exertion from 3yrs of age and right upperlimb for past 6months. Each episode occurs on playing for long time and lasts for about 30minutes to recover. His younger brother 5years old has similar dystonia of both lower limbs alone for past one year and last for 5minutes only.

Birth and developmental history of both were normal. On examination no neurological deficit.

Basic blood investigation were normal. Serum lactate was raised. MRI brain showed bilateral globus-pallidus hyperintensity in both of them. CSF glucose levels was normal. A trial of levodopa didn’t show any benefit. Oral thiamine supplementation grossly reduced the frequency and severity in both the children. Genetic confirmation in the form of whole exams sequencing for the siblings and parents were sent.

Conclusion:

Clinical presentation of isolated PED, positive family history, raised serum lactate, bilateral globus-pallidus hyperintensity, dramatic response to thiamine all favours a firm possibility of pyruvate dehydrogenase deficiency in these case. This case is presented for its rarity and expands the spectrum of PDH deficiency disorders and one should not miss out a treatable condition.