The episodes may be proceeded by intense headache and abdominal pain and are usually self-limiting.

However, other symptomsnamely joint pain, intense headache, insomnia and an extreme degree of prostrationlast for a variable period; usually for about five to seven days.

Despite the pain, he continued with the piece and refused to seek medical treatment for the resulting bump and intense headache which followed.

Yet now she found she couldn't keep her eyes open to read the entries - and she started developing alarmingly intense headaches.

That was when those who had taken the supplement reported 34 per cent less intense headaches and 42 per cent less nausea.