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TABLE 135.4 SIGNS AND SYMPTOMS OF SHUNT INFECTION IN PATIENTS WITHOUT WOUND INFECTION Change in sensorium Irritability Fever Vomiting Adbominal pain Shunt obstruction Adapted with permission from Odio C, McCracken GH, Nelson JD CSF shunt infections in pediatrics: a seven-year experience Am J Dis Child 1984;138:1103–1108 The peritoneal portion of the shunt may become infected through the shunt mechanism or via a primary peritoneal infection Peritoneal infection can result in loculated, cystic pools of infection around the terminal portion of tubing (pseudocysts) These infections may be indolent in their presentation, and the shunt tap from the reservoir may not show evidence of infection Shunt nephritis is a rare but serious complication of ventricular–atrial shunts Renal deposition of antigen–antibody complexes leads to complement activation, which damages the renal tissue Unfortunately, the child with an infected CSF shunt may present with nonspecific signs and symptoms ( Table 135.4 ) Children commonly develop symptoms of shunt malfunction, such as lethargy or irritability Meningismus is not often present Infection may also manifest as abdominal complaints, such as pain or vomiting, especially when the infection involves the distal catheter tip Fever is not always present in patients with shunt infections and is uncommonly the only sign As previously mentioned, infection is most common within a few months of the shunting procedure, is uncommon after months, and is rare more than year afterward These rules are less applicable in patients with gram-negative infections, which can occur later after shunt placement Children with gram-negative infections are more often bacteremic, if not septic appearing A wound infection overlying any portion of the shunt mechanism can manifest as erythema and tenderness or swelling along the shunt tract or over the reservoir A reddened tract of skin paralleling the shunt tubing from the head to chest is often detected and is virtually diagnostic of shunt infection In the absence of overlying infection, aspiration of a small amount of CSF from the shunt system should be performed to identify the presence of a bacteriologic