A system for monitoring an implantable medical device. The system includes an implantable therapeutic substance delivery device for delivering a therapeutic substance, along with a temperature sensor and an indicator device. The delivery device includes a housing maintaining a reservoir for containing the therapeutic substance. Further, the delivery device includes a fill port assembly having a port chamber in fluid communication with the reservoir and including a septum fluidly sealing the chamber. The temperature sensor is associated with the fill port assembly. Finally, the indicator device is adapted to indicate presence of a needle within the port chamber based upon information from the temperature sensor.
