Bilateral hypoxic-ischaemic thalamic lesions in newborns

Bilateral hypoxic-ischaemic thalamic lesions are a rare type of neonatal encephalopathy with characteristic but often misinterpreted clinical features. This article describes history, clinical and diagnostic findings in a preterm and a term infant with hypoxic-ischaemic thalamic lesions after severe and abrupt intrauterine hypoxia. Both neonates presented with absent suckling and swallowing whereas other cranial nerves were unaffected. Characteristic findings in both newborns were profound muscular hypotonia and weak facial expressions together with feeding difficulties and frequent episodes of aspiration pneumonias. The term infant died at the age of 14 weeks following presumed aspiration pneumonia, the preterm infant, however, has developed severe extrapyramidal cerebral palsy. Absent suckling and swallowing with otherwise normal cranial nerve function appears to be characteristic of a bilateral hypoxicischaemic lesion of the thalamus. Animal experiments suggest that these lesions originate from a short but total ischaemia as it can be observed in cord prolapse or total placental abruption. Specific findings may initially be absent on ultrasound examination. Hence, magnetic resonance imaging of the brain should be performed on all patients with characteristic clinical symptoms even if the ultrasound scan is unremarkable. Evidence of bilateral ischaemic lesions of the thalamus usually indicates a poor prognosis.