I have no idea w/ the medical system in KSA, though it could be quiet similar for all GCC. The best thing to do is to inform your HR Manager in the company regarding your illness, and explain to them that it is not harmful and contagious for them, if they have no objection on that, they can be of great help to you and it should be written clearly on the category of the application form for medical that you are an Engineer and the nature of your work is that of an Engineer. Good Luck!