Christiane Licht, Roland Weisser, Christian Schlögl
Maladjustments and failures of programmable ventriculo-peritoneal shunts have been reported in patients encountering powerful electromagnetic fields, e. g. MRI. By the means of the case this study shows an easy maladjustment of a Codman-Hakim programmable valve also by small magnetic fields form everyday hospital life. We describe the case of a 53year old man treated for hydrocephalus with a programmable Codman-Hakim shunt valve. During his hospitalization in Forensic Psychiatry the patient's valve pressure setting changed randomly during despite frequent reprogramming and surveillance. We found that the elctromagnetic locking mechanism of common hospital doors had a strong enough magnetic field to unintentionally change the patient's shunt setting. We assume that already weak magnetic fields (<100 mT) may change the pressure settings of Codman-Hakim shunt valves.