The onus is on you to notify the relevant people. The ATSB are not going to contact your DAME to let them know you have been involved in an accident! If they need medical records then they will approach CASA and that is usually only if it is a fatal accident. If the pilot has survived then it would be expected that they would tell the investigators about any relevant medical history. CASA would not be contacting a DAME to let them know you have been involved in an accident. Their interest only extends as far as any rule breaches. If you don't report an injury suffered during an aircraft accident then they have already got you on one.