Say you had food poisoning and have constant stomach aches and need to use the toilet every 10minute, what would happen give that you provide proper medical certificates etc...
In the case of most Board Developed Courses, if your appeal is upheld you will receive your examination mark or your assessment mark for the examination, whichever is the greater.
Assuming all the medical information is accurate and they grant you special consideration they will remove your exam mark from the moderation process for your cohort. Then they will do the moderation process and slot you in where you would fit e.g. say you were ranked 3rd and 2 marks behind 2nd then you will be moderated to 2 marks behind 2nd. If that gives you a better result than including your exam they will go with that but if including your exam mark would give you the better result then you won't get the special consideration (because you didn't need it).
I have seen this happen a number of times. One year we had one student who literally threw up before three exams but he only got special consideration for one exam - why because his exam marks for the other two exams gave him a better result.