Management of Hydrocephalus due to Posterior Fossa Tumors in Children

Initial Management at Presentation

There is some controversy about initial management. The authors’ preferences are listed below.

• Removal of tumor: It is preferable to excise the tumor during a planned operating theatre time. If the child’s condition deteriorates between the time of admission and the planned surgery time, it is best to proceed to emergency surgical excision of the tumor, rather than temporize with EVD, which often proves inadequate.
• Shunt or ETV if tumor resection cannot be performed: If removal of the tumor is not possible due to operational issues, then it is preferable to place a ventricular shunt first or perform an ETV, and then perform the tumor resection a day or two later. This applies to inoperable infiltrating brainstem tumors.

Adjunctive Therapies

Medications

• Steroids: On admission, most neurosurgeons would begin the administration of dexamethasone (IV preferably). For life-threatening cerebral edema, a child weighing less than 35 kg can initially be given 16.7 mg and then 3.3 mg every 3 hours, while a child weighing 35 kg or more is initially given 20.8 mg and then 3.3 mg every 2 hours (20).
• Acetazolamide: This agent is of limited use. It may have some place in gaining time while waiting for an operating room to become available. Electrolytes and ABGs should be monitored.
• Mannitol: Mannitol is used in cases of acute deterioration on the way to the operating room for emergency treatment. It is administered IV, 0.25 – 1.5 or 2 g/kg over 30 – 60 minutes. It can be repeated, if necessary, 1 – 2 times after 4 – 8 hours (20).

Follow-up

• Watch closely in perioperative period: Close neuromonitoring and VS are necessary. Patients with posterior fossa pathologies are at high risk for acute deterioration, due to the limited space and proximity to the brainstem. The level of consciousness and usual neurological signs are important, but mainly for supratentorial lesions. Pupil diameter and reaction to light are not expected to alter in infratentorial pathologies until the late stages. More critical are the VS (heart rate, blood pressure) and respiratory pattern.