There are distinct clinical situations in which the various methods of treatment are generally used: 1. Medical therapy may be used in the circumstance of an infected, but functioning shunt. However, once a shunt is shown to be malfunctioning, it must be treated surgically to correct both the malfunction and the infection. 2. The one combination therapy that continues to treat the hydrocephalus while obeying surgical principles to remove an infected prosthesis is that of immediate shunt replacement. However, this mode of therapy has worked infrequently. 3. The form of combined surgical and medical therapy that allows time to sterilize the CSF in the absence of a foreign body in situ is that of delayed replacement following removal of the infected shunt. However, this method temporarily discontinues the treatment of hydrocephalus. 4. External ventricular drainage removes the foreign body and continues to treat the hydrocephalus; however, this therapy places the patient at increased risk for more virulent infection. With these points in mind, an algorithm for the treatment of shunt infection can be developed as depicted in Figure 8. Using this common sense approach, most circumstances commonly encountered in the practice of pediatric neurosurgery are dealt with, and the best hope of cure is obtained.