Hi Rachael,
of course, the body will attempt to compensate for the loss of function. Many organs are not absolutely necessary for our survival, but the new way or level of functioning will be compromised and may lead to other complications. The new balance of thyroid hormones by medication can also be a challenge.
So a person who is "never quick enough" ( ((Endocrine - Thyroid - Follicular Epithelium|thyroid)) theme) will rely on her ((Endocrine - Pituitary Gland - Anterior Lobe|pituitary)) and ((Endocrine - Adrenal Gland - Medulla|adrenals)) and that can have implications for her ((Circulatory - System Overview|cardiovascular system)) and her ((Musculoskeletal - System Overview|musculoskeletal system)) for example.