When to to treat progressive hydrocephalus?
The treatment of hydrocephalus has risk. The benefit versus risk must be considered in each patient. Treatment is probably indicated for symptomatic hydrocephalus and for clinically silent hydrocephalus if associated with: (1) a significant increase in ventricular size between two ultrasounds; (2) a slowly progressive ventriculomegaly as detected by ultrasound during a 4-week period; and (3) a moderately increased ventricular size as detected by ultrasound during a 2-week period.

Acetazolamide (100 mg/kg per day) reduces cerebrospinal fluid production by 50%. The combination of acetazolamide and furosamide reduces CSF production by 100%. Neonates on acetazolamide should have serial renal ultrasounds because of the possibility of nephrocalcinosis. The potential toxic effects of acetazolamide on myelination should be discussed with parents before the initiation of treatment. A clinical trial demonstrated the use of these drugs to be ineffective.

Serial lumbar punctures probably work by creating a conduit between the lumbar subarachnoid space and the subcutaneous space. Cerebrospinal fluid leaks through the conduit and is reabsorbed in the subcutaneous space. The risk of serial lumbar puncture is infection.

Direct ventricular drain can be achieved by ventricular taps or the incertion of a catheter into the ventricle. Ventricular taps are seldom done because of the high risk of infection and tissue injury due to multiple taps. Ventricular shunt to an external container is preferred to ventricular taps when direct ventricular drain is needed.

Ventroperitoneal shunt is the definite treatment of progressive posthemorrhagic hydrocephalus. The major risk is infection and shunt malfunction. Ventriculoperitoneal shunt is probably contraindicated until a neonate weighs more than 1500 grams or if a previous lumbar puncture demonstrates cerebrospinal fluid with an increased level of protein (>300 mg), red cells (>1000 cells/mm), or evidence of infection. These treatment options for progressive hydrocephalus are often combined to achieve maximal benefit (Figure 254.1).