Hyperthyroidism is the condition that occurs due to excessive production of
thyroid hormone by the
thyroid gland.
]Thyrotoxicosis is the condition that occurs due to excessive thyroid hormone of any cause and therefore includes hyperthyroidism.
Some, however, use the terms interchangeably. Signs and symptoms vary between people and may include irritability, muscle weakness, sleeping problems, a
fast heartbeat,
heat intolerance,
diarrhea,
enlargement of the thyroid, and
weight loss.
Symptoms are typically less in the old and during
pregnancy. An uncommon complication is
thyroid storm in which an event such as an
infection results in worsening symptoms such as confusion and a
high temperature and often results in death. The opposite is
hypothyroidism, when the thyroid gland does not make enough thyroid hormone.
Attention-deficit hyperactivity disorder (ADHD) is considered to have a biologic basis, but the precise cause is unknown. It is one of the neurodevelopmental abnormalities observed frequently in children with generalized resistance to thyroid hormone, suggesting that thyroid abnormalities may be related to ADHD.