Publication

Abstract : We read with interest the article by Saeedi et al.1 about tongue protrusion dystonia (TPD) in pantothenate kinase–associated neurodegeneration. They also highlighted other important causes of TPD, including tardive dystonia, posthypoxic encephalopathy, neuroacanthocytosis, and Lesch-Nyhan syndrome. Tongue thrusting has also been described in healthy infants with immaturity of neuromuscular function of the orofacial musculature.2 However, rhythmic tongue thrusting and persistence beyond age six months is abnormal and may serve as an early marker of dyskinetic cerebral palsy (CP).3 Here we describe an infant with TPD secondary to kernicterus. This nine-month-old boy presented with global developmental delay and repetitive movements of tongue noted since early infancy. He had a history of bilirubin encephalopathy in the neonatal period requiring exchange blood transfusion on day five of life; maximum documented serum bilirubin was 30 mg/dL. On examination, he exhibited hypotonia with intermittent dystonia involving all four limbs. He had rhythmic tongue thrusting movements (Video) which were not evident during sleep. Neuroimaging revealed bilateral globus pallidus hyperintensities. The child was characterized as evolving dyskinetic CP secondary to kernicterus and began rehabilitative measures. Kernicterus is characterized by choreoathetoid movements, upward gaze restriction, sensorineural hearing loss, and dental enamel hypoplasia.4, 5 However, all these features may not be present simultaneously. Also, the diagnosis of dyskinetic CP is often delayed because of the delayed appearance of athetosis. Rhythmic tongue thrusting, although less commonly described, is often seen in evolving dyskinetic CP and can help in early diagnosis.3 The co-occurrence of a nonprogressive clinical course, with either upward gaze restriction, sensorineural hearing loss, dental enamel hypoplasia, or classical neuroimaging findings may confirm the diagnosis.4, 5