Are people with severe hypertension admitted to the ICU?

That depends on the situation, but the ICU would be the place to treat hypertensive emergencies because ICU's are equipped with the nurses to deal with high blood pressure in an emergency. Untreated high blood pressure that can lead to strokes and even death. In the ICU, nurses administer and titrate (adjust) medications to lower blood pressure. Patients with IV medications must be monitored closely and carefully with a heart monitor in the critical care setting.

Usually yes since they need very close monitoring of their pulse and blood pressure. In addition, they often initially need continuous IV medications to slowly bring their blood pressure down. The immediate danger to very high blood pressure is heart attack and the type of stroke that results in bleeding in the brain. As the blood pressure is lowered slowly, the neurological function needs to be monitored since a too rapid decrease can result in a stroke caused by lack of adequate blood pressure (the brain may become accustomed to a high blood pressure and hasn't adjusted fast enough).