Hypothyroidism. In the event that the thyroid is underactive, it makes too minimal thyroid hormone, causing hypothyroidism. The body goes through vitality all the more gradually, and substance movement (digestion) in the cells eases back down. Hashimoto's thyroiditis is an immune system illness that causes most instances of hypothyroidism in children and teens.The youngster may likewise have a conspicuous expanding of the neck (goiter), as the thyroid organ gets aroused. Different side effects may rise, for example, bizarre tiredness or laziness, dry bothersome skin, expanded affectability to cold, weight gain or summed up growing, poor focus, diminished vitality, and clogging