What is secondary hypertension symptoms

When in the following circumstances should be carefully examined to determine whether the secondary hypertension: (1) patients on the full buck poor response to treatment (including diuretics, and the triple drug use to a maximum dose); (2) in patients with good control of blood pressure before, but now control poor; (3) sudden hypertension; (4), or hypertension and more young people over the age of the elderly hypertensive emergencies; (5) the known secondary hypertension symptoms and signs.