Should i be concerned that my 4 year old has started snoring (adult type snoring) a couple days ago?

Sleep disorder: Sleep disordered breathing is one possible cause. There may be enlarged tonsils and/or adenoids disrupting airflow. A virtual consult may be helpful to you and your physician in reviewing findings.

Some basics: The tonsils & adenoids of kids grow slightly faster than they do up to 6-8 yrs. They then stabilize & become less prominent until the teens/adulthood when they have regressed. Snoring during any URI is common in many from 4-10. If you note any pause in breathing >10 sec this may be part of a sleep apnea problem that would need attention. Sleep apnea is a common reason for tonsil removal in kids.