This document discusses hypothyroidism, which occurs when the thyroid hormone level decreases. It can be congenital or acquired after age 1. Congenital hypothyroidism can lead to cretinism if untreated. Clinical manifestations include poor growth, feeding issues, constipation, dry skin, jaundice, and delayed development. Diagnosis involves tests of thyroid hormones and antibodies. Treatment is lifelong thyroid hormone replacement therapy to normalize thyroid stimulating hormone levels. Nursing care involves early identification, assisting with testing and treatment, educating parents, and ensuring proper follow up.