Hypothyroidism Flashcards
Hypothyroidism can be c____ or acquired
congenital
Thyroid hormone is essential for d____ and f______ of the b____ and b___
development and functioning of the brain and body
Undiagnosed hypothyroidism can cause problems with n_____ and i_____ d_____ in children
neurodevelopment and intellectual disability
True of false: congenital hypothyroidism is screened for?
True
During newborn blood spot screening test
What is the most common cause of acquired hypothyroidism?
Autoimmune thyroiditis (AKA Hashimoto’s thyroiditis)
Which antibodies is Hashimoto’s thyroiditis associated with?
Anti-Thyroid Peroxidase (anti-TPO) antibodies and Antithyroglobulin Antibodies
Hashimoto’s thyroiditis is associated with other autoimmune conditions, particularly…
T1DM and Coeliac disease
What are symptoms of hypothyroidism?
Fatigue and low energy
Weight gain
Poor growth
Poor school performance
Constipation
Dry skin
Hair loss
Cold intolerance
Menorrhagia (heavy periods)
What are some signs of hypothyroidism
Bradycardia
Slow reflexes
Cold hands
Goitre (in Hashimoto’s and iodine deficiency)
Pretibial myxoedema
What investigations are there for hypothyroidism?
Full thyroid function blood tests (TSH, T3 and T4)
Thyroid ultrasound
Thyroid antibodies
How do you manage hypothyroidism?
Levothyroxine, once daily
Dose titrated depending on thyroid function tests and symptoms.
Who is most at risk of hypothyroidism?
Women, ageing and postpartum
What is the most common cause of hypothyroidism in the developed world?
Hashimoto’s thyroiditis (autoimmune)
What are the most common causes of hypothyroidism in the developing world?
Iodine deficiency and postpartum thyroiditis
What is the mechanism of postpartum thyroiditis?
Same as Hashimoto’s thyroiditis, autoimmune. Present during pregnancy. However, resolves itself within 1 year of symptoms..
How does amiodarone (anti-arrhythmia medication) affect thyroid function?
Amiodarone has high iodine content and can prevent conversion of T4 to T3 (more active state). Leads to hypothyroidism despite high/normal levels of T4.
Can also cause inflammation of thyroid gland itself, initially causing release of thyroid hormone (hyperthyroidism) but then progresses to hypothyroidism due to damaged tissue.
What is De Quervain’s thyroiditis?
Inflammation of thyroid gland, perhaps due to coxsackie virus.
Initial stage, release store thyroid hormones causing hyperthyroidism.
As inflammation resolves, thyroid’s ability to produce hormones impaired leading to transient hypothyroidism.
Thyroid function normally returns as gland recovers.
Secondary _____ can also cause hypothyroidism
hypopituitarism
Hypothalamus fails to produce enough TRH to stimulate the pituitary gland to produce TSH.
What are the TSH and T4 levels in primary hypothyroidism (Hashimoto’s thyroiditis)?
High TSH
Low T4
What are the TSH and T4 levels in secondary hypothyroidism?
Low TSH
Low T4
What are the TSH and T4 levels in subclinical hypothyroidism?
High TSH
Normal T4
Those with hypothyroidism will commonly also have _____
anaemia
Why is anaemia associated with hypothyroidism?
Hypothyroidism slows down overall metabolic activity in the body which includes bone marrow’s production of erythropoietin so fewer RBCs produced.
Also can cause changes to iron absorption.
Can also cause menorrhagia so more blood loss.
What is a complication of hypothryoidism?
Myxoedema coma
