1. Department of Gastroenterology, Hospital Universitario Rio Hortega, Valladolid, Spain;
2. Department of Gastroenterology, Hospital de Cabueñes, Gijón, Spain;
3. Department of Gastroenterology, Hospital General Universitario de Alicante, Alicante, Spain;
4. Department of Gastroenterology, Hospital de Ciudad Real, Ciudad Real, Spain;
5. Emergency Department, Hospital Universitario Rio Hortega, Valladolid, Spain.