Some years back I was learning to fly the mighty Wessex at the RAF school of Air Traffic Control.
On my first night circuit I suffered a hydraulic failure so I called "*** PAN, PAN, PAN, hydraulic failure, request runway 36 for immediate landing!"etc.
The answer came back from ATC "Aircraft calling PAN - wait out. Callsign calling for rejoin - say again details?"
My instructor to ATC "We didn't say practice, you know!"
ATC: " Oh, in that case clear to land!"
Ah, yes, the school of excellence
Sorry, that was off topic. I think that PAN is sufficient to alert ATC, followed by an explanation of the problem when asked to pass details. An ambulance can always be requested by the crew to meet the a/c.