Dopa-Responsive Dystonia in a Ten-Year-Old Girl
A ten-year-old girl was brought with complaints of difficulty in walking and stiffness of both lower limbs, for the past six months. She also had a history of frequent falls while walking and was unable to stand for prolonged periods. Her antenatal, birth, and neonatal periods were uneventful and developmental milestones were appropriate for her age. There was no family history of similar illness. On examination, her higher mental functions were normal, speech was hypophonic; she had a gait disturbance characterized by leg stiffness, and a tendency to walk in an equinus posture, resulting in difficulty in balancing. Her tone was slightly increased in all the four limbs, with cog-wheel rigidity. Power in both upper limbs was normal and 4/5 in the lower limbs. Postural tremor and dystonia were noticed on attempted movements of the limbs. Deep tendon reflexes in all the four limbs were exaggerated with extension of both great toes (striatal toes). Clonus was absent. The sensory system and cranial nerve examination were normal. There were no cerebellar signs. In the hospital, it was found that the symptoms and signs were relatively mild in the morning during rounds, whereas, they gradually worsened as the day progressed, rendering the child almost unable to walk by evening. The peripheral blood smear study was normal. Serum electrolytes and serum Ceruloplasmin were in normal range. Slit lamp evaluation for Kayser Fleischer ring was negative. Magnetic resonance imaging (MRI brain and spine were normal. In view of the typical diurnal variation of dystonia, a therapeutic challenge with levodopa/carbidopa was tried and there was a dramatic decrease in dystonia within two days and the child's gait improved. Hence, a diagnosis of DRD was made. The child was treated with a combination of Levodopa, Carbidopa, and Trihexyphenidyl. On follow-up the child showed persistent improvement in the clinical condition. Genetic studies were planned, but could not be done due to lack of resources.