A 7-year-old child with severe perinatal hypoxic-ischemic encephalopathy presents with new-onset ataxia, intention tremor, and dysarthria over 3 days. MRI shows increased T2 signal in the subthalamic nuclei bilaterally. What is the most likely diagnosis?

• A Bilateral striatal necrosis (HIE-related) ✓
• B Dentatorubral-pallidoluysian atrophy
• C Acute necrotizing encephalopathy
• D Acute cerebellar ataxia

Explanation

In term neonates with severe acute HIE, injury characteristically affects the basal ganglia, thalami, perirolandic cortex, and subthalamic nuclei. This produces a delayed-onset movement disorder with ataxia, tremor, and dysarthria, often emerging days to weeks after the insult. MRI showing bilateral subthalamic and basal ganglia changes is characteristic. Acute cerebellar ataxia is post-infectious and symmetric without subthalamic lesions.

Reference: Nelson Textbook of Pediatrics, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.