AKT-2533

A mother brings her 9-year-old son who has been vomiting for the last day. He reports that since he was 4 years old he has had vomiting episodes 6 to 10 times a year every 4 to 8 weeks. The episodes last for around a day and no clear trigger has been found. He is a well and happy child who is able to eat, drink and gain weight appropriately between these episodes.

He has been thoroughly investigated previously and he has been diagnosed with cyclical vomiting syndrome (CVS).

He has now developed a new symptom associated with his attacks where he complains of abdominal pain, headache, and a sensitivity to light and noise.

What is the most likely cause of this new set of symptoms?