Researchers aim to improve the way that physicians identify problems with a shunt system
By: Jacob Getzoff and Dr. Jenna Koschnitzky, HA Director of Research Programs
Shunt placement is the most common treatment for those living with hydrocephalus, but complications within a shunt system can develop over time. Persistent headaches, vomiting, and drowsiness are all signs that a shunt system may not be functioning properly. While these symptoms are associated with shunt dysfunction, the symptoms could also be indicative of an illness or disorder not related to the shunt. This poses a challenge for our community and for physicians. In addition, when the symptoms are related to the shunt system, the symptoms do not tell physicians which part of the shunt is not functioning properly.
In many cases, diagnostic imaging, such as CT scans or X-rays, is performed to rule in or rule out shunt dysfunction. These imaging tests expose patients to radiation, and many times these tests indicate that the shunt is in fact working properly. Although a working shunt is good news for a patient with hydrocephalus, unnecessary radiation exposure is not.
Researchers at the University of Zürich asked the question, “Is there a better way to diagnose shunt dysfunction and reduce radiation exposure?” The team analyzed data from the medical records of 148 adult patients admitted for suspicion of a shunt dysfunction at the University Hospital of Zürich. They analyzed the data for commonalities between the cases that could help them optimize the diagnostic process.
The researchers found that only 46% of patients admitted had a shunt dysfunction, while the vast majority of the remaining 54% were unnecessarily subjected to radiating diagnostic procedures. After analyzing patient symptoms, they found that an abdominal cyst is highly indicative of abdominal dislocation. However, for all other types of shunt dysfunction observed, they were unable to identify any specific symptom or combination of symptoms that could reliably differentiate shunt dysfunction from other diagnoses.
While the analysis of symptoms did not show much potential for improving diagnostics, the researchers did find a relationship between why a shunt stopped working properly and how long ago the shunt was implanted (Table 1). In these adult patients, infections and abdominal dislocations were most common in the first six months, over-drainage and under-drainage were most common from six months to four years, and disconnections, kinking, and laceration were most common four years or more after shunt placement. The rate of shunt obstruction (blockage) was steady during all time periods after six months.
Using this new information, the researchers devised a decision tree to help reduce the use CT scans and X-rays in adults with symptoms of shunt dysfunction. However, the effectiveness of this decision tree still needs to be evaluated and is the subject of a subsequent study that is currently under way at the University of Zürich.
The research team consisted of José M. Spirig, Melanie N. Frank, Luca Regli, and Lennart H. Stieglitz. The full article can be found here.