Why hypertension is called silent killer?

HTN: one may not show clinical symptoms when Blood pressure is elevated. Hence, called the silent killer....

Blood vessel disease: Hypertension (HTN) is called silent killer because it typically has no obvious symptoms, so many people don’t even know they have HTN. HTN develops over time and may lead to complications like higher risk of heart and kidney diseases that may be deadly if left untreated. That’s why it’s important to have your blood pressure checked regularly (how regularly depends on whether you have HTN).