Hypothyroidism (myxoedema) Flashcards
1
Q
What are the symptoms of hypothyroidism?
A
- Tiredness
- Sleepy
- Lethargic
- Decreased mood
- Cold intolerance
- Increased weight
- Constipation
- Menorrhagia
- Hoarse voice
- Decreased memory/cognition
- Dementia
- Myalgia
- Cramps
- Weakness
2
Q
What are the signs of hypothyroidism?
A
- BRADYCARDIC
- Dry thin hair/skin
- Yawning
- Cold hands
- Ascites
- Round puffy face/double chin/obese
3
Q
How is hypothyroidism diagnosed?
A
- Raised TSH
- Low T3 and T4
- Raised cholesterol and triglyceride
- Macrocytosis
4
Q
What are the causes of primary autoimmune hypothyroidism?
A
- Primary atrophic hypothyroidism
- Hashimoto’s thyroiditis
5
Q
What is Hashimoto’s thyroiditis?
A
- Hashimoto’s thyroiditis, also known as chronic lymphocytic thyroiditis, is the most common cause of hypothyroidism in the United States.
- It is an autoimmune disorder in which antibodies directed against the thyroid gland lead to chronic inflammation.
6
Q
What are the other causes of primary hypothyroidism?
A
- Iodine deficiency
- Post-thyroidectomy or radioiodine treatment
- Drug-induced
- Anti-thyroid drugs
- Amiodarone
- Lithium
- Iodine
- Subacute thyroiditis
7
Q
What are the causes of secondary hypothyroidism?
A
- Not enough TSH - very rare
8
Q
What are some hypothyroidism’s associations?
A
- Other autoimmune diseases
- T1DM
- Addisons
- Turners syndrome
- Down’s syndrome
- Cystic fibrosis
- Primary biliary cholangitis
- Ovarian hyperstimulation
- Genetic
9
Q
What are the problems in pregnancy with hypothyroidism?
A
- Eclampsia
- Anaemia
- Prematurity
- Decreased birthweight
- Stillbirth
- Post partum bleeding
10
Q
How is hypothyroidism treated?
A
- Levothyroxine
- Review dose at first 12 weeks
- Check TSH yearly once normal
- Treat the patients symptoms not the blood level but try and keep TSH levels at >0.5mu/L
- Thyroxine’s half life is 7 days so wait 4 week before checking TSH to see if a dose change is right
- Small changes in serum free T4 have a logarithmic effect on TSH
- Enzyme inducers increase the metabolism of levothyroxine
11
Q
How does amiodarone cause both hyper and hypothyroidism?
A
- Amiodarone is high in iodine and is structurally like T4
- 2% of users will get significant thyroid problems from it
- Hypothyroidism can be caused by iodine excess
- T4 is release is inhibited
- Hyperthyroidism may be caused by a destructive thyroiditis causing hormone release
12
Q
How are amiodarone induced thyroid problems treated?
A
- Glucocorticoids - when radioiodine uptake is undetectable
- Thyroidectomy may be needed is amiodarone cannot be discontinued
- Check TFTs every 6 months when on amiodarone
- Amiodarone has a half life of 80 days so problems may persist after withdrawal
13
Q
What is myxoedema coma?
A
- The ultimate hypothyroid state before death
14
Q
What is subclinical hypothyroidism?
What risks do they carry?
A
- When TSH is elevated but T3 and T4 are still in normal range
- There is a risk of progression to clinical hyopthyroidism
- The risk doubles when thyroid peroxidase antibodies are present
- The risk is also increased in men
15
Q
How is subclinical hypothyroidism managed?
A
- Confirm that raised TSH is persistent (recheck in 2-4 months)
- Recheck the history and if any non-specific symptoms are present such as depression then consider treating
- Treat if:
- TSH >10mu/L
- Positive for thyroid autoanitbodies
- Past (treated) Grave’s
- Other organ specific autoimmunity as they are more lielly to progree to clinical hypothyroidism, such as
- Diabetes (type 1)
- Myesthenia gravis
- pernicious anaemia
- vitiligo
- If symptoms improve after 6 months, continue, if not then discontinue
- If patients do not fall into any of the above categories, then monitor TSH yearly
