Disclosures: Stephanie Miller, DO: Nothing to disclose

Case Description: The patient presented with intractable headache without focal deficits and was found to have a large pilocytic astrocytoma in her fourth ventricle causing cerebellar and brainstem mass effect. She underwent suboccipital craniotomy and complete resection of the tumor. Postoperative course was complicated by hydrocephalus requiring endoscopic third ventriculostomy, bilateral abducens nerve palsy, bradykinesia, ataxia, tone fluctuations, and dysarthria. Initially she was ambulatory and able to communicate verbally. She developed progressive cerebellar mutism, significant extremity weakness, truncal hypotonia, and ambulatory dysfunction peaking by postoperative day 8-9 and was diagnosed with posterior fossa syndrome (PFS). Cognition seemed spared as she communicated coherently through eye gaze. Gradual motor function recovery started around 5 weeks. After 8 weeks, she began to have slowed dysarthric vocalizations with prompting.

Setting: Tertiary care pediatric hospital.

Patient: 15-year-old girl with low grade pilocytic astrocytoma and obstructive hydrocephalus.

Assessment/Results: On discharge to an outpatient rehabilitation day program around 4 months, MRI was notable for central medulla signal changes. By 6 months, she was ataxic but ambulating with minimal assistance with a walker and sitting unsupported for 15 minutes.

Discussion: Classically PFS is a constellation of postoperative signs and symptoms including mutism, ataxia, emotional lability, behavioral abnormalities, and cranial nerve palsies without MRI findings. This patient’s presentation was consistent with PFS as her strength returned to baseline with persistent ataxia and dysarthria; however, her recovery was notably inconsistent with most published cases of PFS due to significantly prolonged motor recovery time. Interestingly, she eventually demonstrated brain stem involvement on MRI. In hindsight, the authors theorize that some of the patient’s symptoms may not have been purely PFS but rather Wallerian degeneration into the brainstem due to the temporal relationship with gradual loss and recovery of motor function.

Conclusion: Diagnostically, temporary mutism and tetraparesis postoperatively can be PFS but other anatomic factors should be considered.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/prolonged-tetraparesis-in-posterior-fossa-syndrome-a-case-report/