Hypothyroidism Flashcards
The thyroid gland wraps around the cricoid cartilage. But which vertebrae does the thyroid gland align with?
1 - C1-C2
2 - C2-C3
3 - C5-T1
4 - T2-T4
3 - C5 -T1
Label the image below using these labels:
- thyroid cartilage
- cricoid cartilage
- right lobe of thyroid gland
- isthmus
- left lobe of thyroid gland
- trachea
1 - cricoid cartilage
2- right lobe of thyroid gland
3 - trachea
4 - isthmus
5 - left lobe of thyroid gland
6 - thyroid cartilage
In order for thyroid hormones triodothyronine (T3) and thyroxine (T4) to have an affect at tissue throughout the body there are 3 stages of the positive feedback loop. These are essentially the stages that result in T3 and T4 being secreted and reaching the target tissue. Which of the following is NOT one of these stages?
1 - hypothalamus signals the pituitary gland
2 - T3 and T4 in the blood signal only the hypothalamus as part of the negative feedback loop
3 - pituitary gland signals the thyroid gland
4 - triiodothyronine (T3) signalling in tissue and thyroxine (T4) signalling in the circulation
2 - T3 and T4 in the blood signal only the hypothalamus as part of the negative feedback loop
- T3 and T4 signal both the hypothalamus and pituitary gland
There are 3 common thyroid tests that are conducted, namely thyroid stimulation hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4). What are the normal levels of TSH secretion?
1 - 0.3 - 3.5 mU/L
2 - 0.3 - 7.5 mU/L
3 - 1.3 - 5.5 mU/L
4 - 3.5 - 7.5 mU/L
1 - 0.3 - 3.5 mU/L
There are 3 common thyroid tests that are conducted, namely thyroid stimulation hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4). What are the normal levels of FT4 secretion?
1 - 1 - 2.5 pmol/L
2 - 1.5 - 2.5 pmol/L
3 - 10 - 25 pmol/L
4 - 100 - 250 pmol/L
3 - 10 - 25 pmol/L
There are 3 common thyroid tests that are conducted, namely thyroid stimulation hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4). What are the normal levels of FT3 secretion?
1 - 0.5 - 3.5 pmol/L
2 - 3.5 - 7.5 pmol/L
3 - 35 - 75 pmol/L
4 - 350 - 750 pmol/L
2 - 3.5 - 7.5 pmol/L
What is the prevalence of hypothyroidism?
1 - 4/100
2 - 4/1000
3 - 4/10,000
4 - 4/100,000
2 - 4/1000
Is hypothyroidism more common in men or women?
- women
- especially aged >40 y/o
Hypothyroidism is a lack of thyroid hormones and can be primary (thyroid related) or secondary (hypothalamus/pituitary gland) related. Which of the following is NOT a symptom of hypothyroidism?
1 - cold intolerance (where lots of clothes)
2 - weight loss
3 - facial puffiness
3 - tiredness and fatigue
4 - low mood
5 - heavy menstrual periods (impaired ovarian follicular development)
6 - hoarse voice
7 - myalgia and weakness
2 - weight loss
- patients typically gain weight
Hypothyroidism is a lack of thyroid hormones and can be primary (thyroid related) or secondary (hypothalamus/pituitary gland) related. Which of the following is NOT a clinical sign of hypothyroidism?
1 - tachycardia
2 - reflex reduced (hypo reflexia)
3 - ataxia
4 - dry/thin hair
5 - cold hands
6 - ascites
7 - round puffy face
8 - goitre
9 congestive cardiac failure
1 - tachycardia
- typically causes bradycardia
- severe cases it can cause coma or stupor (near unconsciousness)
Although rare what is a sign that can may be detected on patients legs in Hashimotos disease?
1 - cellulitis
2 - dermatitis herpetiformis
3 - pretibial myxoedema
4 - all of the above
4 - all of the above
- caused by a build up of glycosaminoglycans in the dermis and subcutis of the skin can be seen in Graves disease (hyperthyroidism)
Primary hypothyroidism is when there is a dysfunction of the thyroid causing low thyroid hormones. Which of the following is NOT a cause of primary hypothyroidism?
1 - autoimmunity
2 - infection (thyroiditis)
3 - drug interactions
4 - congenital hypothyroidism
5 - iodine deficiency
6 - under active pituitary gland
7 - post hyperthyroidism treatment
6 - under active pituitary gland
- secondary hypothyroidism
- but is very rare
Primary hypothyroidism is when there is a dysfunction of the thyroid causing low thyroid hormones. Which of the following is the leading cause of primary hypothyroidism worldwide (but not in the UK)?
1 - autoimmunity
2 - infection (thyroiditis)
3 - drug interactions
4 - congenital hypothyroidism
5 - iodine deficiency
6 - post hyperthyroidism treatment
5 - iodine deficiency
Primary hypothyroidism is when there is a dysfunction of the thyroid causing low thyroid hormones. What is a common cause of hypothyroidism where no goitre is present?
1 - autoantibodies against TSH
2 - lymphocytes infiltrate the thyroid causing atrophy
3 - adenoma causing a reduction in thyroid hormone release
4 - overactive pituitary gland
2 - lymphocytes infiltrate the thyroid causing atrophy
Thyroid peroxidase (TPO) is an enzyme expressed mainly in the thyroid where it is secreted into colloid. TPO oxidizes iodide ions to form iodine atoms and then allows the formation of thyroxine (T4) or triiodothyronine (T3) through the addition of iodine molecules. If antibodies against TPO are produced, what can this lead to?
1 - Cushing disease
2 - Hashimoto thyroiditis
3 - Addison’s disease
4 - Graves disease
2 - Hashimoto thyroiditis
- most common cause of primary hypothyroidism in countries where iodine is fortified in foods
- destroy thyroid function
- TPO antibodies are not present in healthy thyroid
- if TPO antibodies are present suggest autoimmune disease (commonly hypothyroidism)
Primary hypothyroidism is when there is a dysfunction of the thyroid causing low thyroid hormones. This can be caused by autoantibodies against Thyroid peroxidase (TPO) or thyroglobulin, meaning no or low thyroid hormones, which is called Hashimoto thyroiditis. Do these patients typically have a goitre?
- yes
- hyperplasia and hypertrophy of follicular cells to try and increase thyroid hormone secretion
- eventually thyroid function stops though
Autoimmunity is a common cause of hypothyroidism. Which of the following are associated with autoimmune hypothyroidism?
1 - Addisons disease (low cortisol)
2 - T1DM
3 - Pernicious anaemia
4 - all of the above
4 - all of the above
In a patient with primary hypothyroidism, would we see high or low thyroid stimulating hormone (TSH) levels?
- LOW TSH
no negative feedback means hypothalamus and pituitary gland go into overdrive - increased thyrotropin releasing hormone and TSH
In a patient with primary hypothyroidism, would we see high or low levels of thyroxine (T4) and triiodothyronine (T3)?
- T3 and T4 will both be low
- issue is with thyroid so it doesn’t respond to increases thyroid stimulating hormone
In a patient with secondary hypothyroidism (affecting the hypothalamus or pituitary gland), would we see a high or thyroid stimulating hormone (TSH)?
- TSH and/or thyrotropin levels (TRH) can be low
- ultimately causes low T3 and T4
In a patient with secondary hypothyroidism (affecting the hypothalamus or pituitary gland), would we see a high or thyroxine (T4) and triiodothyronine (T3)?
- T3 and T4 will be low because TSH and/or thyrotropin levels (TRH) can be low
If a patient presents with high levels of thyroid stimulating hormone and lower levels of T3 and T4, what blood test can help determine if it is primary or secondary hypothyroidism?
1 - TFTs
2 - LFTs
3 - Renal Function
4 - Thyroid auto-antibodies
4 - Thyroid auto-antibodies
- if thyroid peroxidase or thyroglobulin auto antibodies are present suggest primary cause such as Hashimoto disease
What is the 1st line treatment for a young and health patient diagnosed with hypothyroidism?
1 - Levothyroxine
2 - Carbimazole
3 - Propylthiouracil
4 - Teriparatide
-1 - Levothyroxine
- synthetic thyroxine (T4)
- titrate as appropriate to maintain normal TSH levels
- dosage needs to be reduced in elderly or IHD patients
Levothyroxine is the 1st line medication for hypothyroidism. However, if the dose is too high, does this cause an increase or decrease in TSH?
- reduced TSH
- negative feedback from T3 and T4 will induce a reduced TSH
- low TSH can exacerbate hypothyroidism further
Which medication should be stopped or carefully monitored for its risk of causing hypothyroidism?
1 - Verapamil
2 - Adenosine
3 - Bisoprolol
4 - Amiodarone
4 - Amiodarone
- similar structure to T4
- can cause hypothyroidism and low TSH
Which of the following medications should be carefully monitored due to its effect on inhibiting thyroidal iodine uptake, iodotyrosine coupling, altering thyroglobulin structure, and thyroid hormone secretion, resulting in hypothyroidism and goiter formation?
1 - Lithium
2 - Adenosine
3 - Bisoprolol
4 - Ramipril
1 - Lithium
Which 2 of the following is hypothyroidism associated with?
1 - Down syndrome
2 - Ulcerative colitis
3 - Irritable bowel syndrome
4 - Turners syndrome
1 - Down syndrome
4 - Turners syndrome
