Hi. My 4 year old son was just diagnosed with a Coronary Artery Fistula. It is 1.3 millimeters in size. My doctor is awaiting other opinions at the moment since this is a rare condition. My son has had a full blood panel, blood gasses, chest x-ray and evaluated by an ENT for tonsils or adenoid abnormality. All the tests showed everything was good and within normal limits. However, his temperature seems to drop significantly at night time. It drops to 95 degrees. Tonight, I noticed 1 ear was 95 and was ear was 96 degrees. It was probably because the way he was sleeping. Although, it is still really low at night. A few times, his coloration looked off, almost a bluish color. His coronary doctor said the discoloration wouldn t be because of his heart since the blood pumping in that area was good and not blue. I was wondering why his temperature drops so significantly at night and also if surgery is needed for a fistula so small in size?