Talk to Pediatric Endocrinologist on High Bp In 13 Years Old Teen

My younger brother who is 13 years old, height 5’9, weight 96 kgs which is obeese, his bp raises to 160/100, sometimes following when he eats something salty, or even when he gets angry or emotional. However i had taken him to cardiologist, paeds nephrologist, they said that his kidney and heart are well, show him to peads endocrinologist otherwise this is obesity related, my question was that this high bp of 145-150/95 every few days recurring, is it really something solely caused by obesity or is it an underlying issue.