Complications of Therapies for Shunt Infections in Children
Overall complication rate 6%: Less than 6% of patients who require shunt extraction and EVD placement are prone to suffer noninfectious complications (131).
Loculated hydrocephalus:Patients who have experienced shunt infection with associated ventriculitis can develop loculated hydrocephalus. These patients can be a challenge to manage due to inadequate drainage of all the compartments filled with CSF. Sometimes these cases require more than one system; however, an effort should be made to minimize the use of shunt hardware when communicating isolated compartments. Endoscopy with fenestration of these pockets of fluid can be one solution for isolated compartments that decreases the need for additional ventricular catheters.
Seizure disorders: Infection can cause serious damage of the brain cortex, often leading to seizure disorders that may require antiseizure medications.
Intellectual impairment: Shunt infection early in life can lead to cognitive impairment later, especially in patients with spina bifida (107).
Malposition of catheter: The insertion of catheters at depths that are too deep or too shallow can be avoided by careful premeasurement of the desired depth of catheter insertion. The use of a stylet will direct the catheter into place and can be useful for insertion of catheters into cysts that need to be drained. Careful preoperative planning and evaluation of imaging studies are needed, however, to determine if this procedure is safe for a particular patient. Some favor drilling a new bur hole to avoid placing a new catheter into an infected surgical wound. However, evidence suggests that there is no difference in management, and the old proximal catheter tract can be used, thereby avoiding a new trajectory with its known complications. Endoscopic placement of catheters has proved to reduce the complication rates associated with malposition or inadvertent injury to vascular and neural structures, especially in those patients with slit or loculated ventricles. However, these disposable endoscopes are not widely available, and their cost can be a significant burden in developing countries. Some surgeons prefer to insert the catheter without the stylet using the tract of the shunt that has been just removed, considering it will slide without resistance into the ventricular cavity. CSF flow should always be checked, and if there is any doubt, imaging should follow to verify the catheter’s position (131).
Vascular injury and hemorrhage: When removing a proximal catheter, the proximity of its tip to the choroid plexus should be taken in consideration. When there is concern for choroid plexus entanglement with the catheter, a stylet can be inserted into the catheter’s lumen and the Bovie cautery instrument is used to deliver short bursts of coagulation to the stylet as it is removed, checking for CSF flow and catheter release. This technique should be avoided in a catheter whose tip dwells in parenchyma, especially near the basal ganglia or striatum or when the tip is near a vasculature structure. If, upon catheter extraction, there is evidence of bloody CSF, the EVD catheter is inserted, and irrigation with warm saline is usually sufficient to arrest the bleeding from the choroid plexus. Evidence of hemorrhage after placement of EVD is not infrequent, with one study citing up to 33% of hemorrhagic episodes after the catheters have been inserted; however, most of these bleeds are not clinically significant (101).
Abdominal injury and distal shunt failure: Abdominal adhesions frequently develop with severe CSF shunt infections. Their presence can complicate reinsertion of a catheter into the peritoneal cavity and increase the risk for bowel injury during insertion. The adhesions can be so severe as to preclude future use of the peritoneal cavity for CSF drainage.
Metabolic complications of antibiotics: Complications associated with antimicrobial therapy depend on the dosage, length of treatment, and associated pathologies. Renal, bone marrow, and cochlear toxicity should be monitored according to the antimicrobial agent used.
Loss of IV access: Patients can develop complications related to long-term need for IV access, especially in the small child.