Complications of Therapies for Medulloblastomas in Children

Complications After Surgery

• Postoperative hematoma: Hematomas in the posterior fossa may be rapidly life-threatening and should be evacuated immediately if they are large and/or are causing symptoms.
• Acute hydrocephalus: Hydrocephalus may result from cerebellar swelling or obstruction of CSF pathways by blood products or residual tumor.  If it is symptomatic, immediate ventriculostomy placement should be performed.
• Infection/meningitis: Bacterial meningitis as well as aseptic meningitis should be ruled out in patients who are febrile, excessively irritable, or have meningismus.
• Vascular injury: There can be injury to the PICA, vertebral artery, or transverse sinus during the surgery that can result in swelling and/or a stroke.
• Cranial nerve injury: Injury to the cranial nerves during the tumor’s removal may result in abducens palsy, facial weakness, hearing loss, or vocal cord paralysis.
• Brainstem injury: Injury to the brainstem can cause cranial nerve palsy and/or hemiparesis.
• Pseudomeningocele and/or CSF leak: When either of these occurs, hydrocephalus must be ruled out.
• Cerebellar injury: Injury to the cerebellum from surgery can cause ataxia, dysmetria, or nystagmus.
• Refractory nausea/vomiting: These can arise when the area postrema is irritated or injured by the surgery.

Posterior Fossa Syndrome (a.k.a. Cerebellar Mutism)

• Onset postoperative days 1–4: Posterior fossa syndrome typically develops 1–4 days after surgery, even when patients demonstrate normal speech immediately after their surgery.
• Multiple signs: The syndrome includes mutism, emotional lability, and possibly other neurological deficits.
• Mutism is typically transient: The mutism resolves after several weeks, although not always completely. Although previously the posterior fossa syndrome was described as a temporary phenomenon, more recent studies have noted that personality changes and language disorders may persist for extended periods of time or permanently (24). Neuropsychological testing will be able to document sequelae and lead to recommendations for therapy as well as other interventions to maximize school performance.
• Unclear pathophysiology: Multiple etiologies have been proposed, but none have been definitively proven (25).