A Silent Killer

Google the words Silent Killer and the website that pops up first says:

Many diseases are silent killers in that they are silent (no symptoms or only vague symptoms), and that they are deadly. There are a number of diseases that are known as “silent killers” because they gradually consume you without causing any serious symptoms in the early stages. Regular medical checkups and early diagnosis of unexplained or vague symptoms can safe your life . . .