Neurodegenerative Diseases USMLE Step 1 Practice Question
A 2-month-old male presents with progressive head circumference enlargement, persistent vomiting, and irritability. Vital signs show HR 145 bpm, RR 38/min, BP 92/58 mmHg, temperature 37.2°C. Head circumference increased 2 cm in 2 weeks. Fontanelle is tense and bulging. MRI demonstrates cystic dilation of the fourth ventricle, cerebellar vermis hypoplasia, and enlarged posterior fossa. No seizures have occurred. Which diagnosis best explains these findings?
Answer choices
- AChiari I malformation
- BDandy-Walker malformationCorrect answer
- CChiari II malformation
- DHoloprosencephaly
- ESyringomyelia
- FMega cisterna magna with enlarged posterior fossa but intact cerebellar vermis
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