At my airline we will contact an outfit called medilink in the USA and give them conditions of your ilness, questions and details are written on a form we carry. A doctor will consider ttt evidence and decide if the condition is serious enough to warrant diversion. Apparently they have saved the company tens of thousands by allowing flighrs to continue when in the past the Captain might have chosen to divert.

We had a pax who had an epelectic fit and the advice was keep going but we had medical.staff on board as passengers who had given him some care and were able to knowledgeably use the medical kit if need be. Can not remember the contents bit some stuff you need to know what you are doing with it.

Oddly enough when we got to the Cannaries he refused to be looked at by paramedics and just wanted to get to the hotel bar for a drink.

I guess he had paid to go on holiday and not to hospital and had probably previously suffered from fits so.was not unduly concerned.

I would imagine in yyou case food poisoning is something often seen and as long as you remain consiouse and not showing signs of shock etc

I think EK uses that service too, there is a handset on the galley wall near the ML2 door on their A380s that has a "medlink" sticker on it.

Medlink
 

A lot of airlines use medlink and the service is very good but the chances of having a medical professional on the aircraft are very high.

Both the medical diversions that I have had to carry out resulted in an immediate diversion on the advice of a doctor who was one of the passengers and I had no time to call medlink due to the urgency of the situation and the proximity of diversion options. ( one heart attack one stroke ).

Interestingly the cabin crew made the correct diagnosis before the doctor had the chance to examin the ill person.