Thyroid Gland Flashcards
What level of TSH will you find in a patient with primary hypothyroidism, where the thyroid gland has been destroyed by the immune system?
a High TSH
b Low TSH
c Normal TSH
a
Describe the control of thyroid activity.
What medication do we use to treat primary hypothyroidism? How do we know when the dose is enough?
levothyroxine
increase dose until TSH falls to normal
Name an autoimmune disease that results in hypothyroidism.
Hashimotos
Describe Graves’ Disease
Describe the presentation of Grave’s Disease.
What causes exophthalmus in Graves’ disease?
Other antibodies bind to muscles
behind the eye and cause exophthalmos
can cause blindness
What is this?
Exophthalmos
What causes pretibial myxoedema in Graves’ disease?
Other antibodies cause pretibial myxoedema (hypertrophy)
What do we call the swelling (non-pitting) that
occurs on the shins of patients with Graves’ disease: growth of soft tissue?
Pretibial myxoedema
What is this?
Pretibial myxoedema
How would a radioactive iodine-reuptake scan of a Graves’ thyroid gland appear?
Diffuse goitre of moderate size and uniform radioiodine uptake
What is Plummer’s disease?
How does a pt with plummer’s disease present differently to a pt with Graves’
*NO pretibial myxoedema
*NO exophthalmos
How would a radioactive iodine-reuptake scan of a toxic nodular thyroid gland appear?
not smooth uptake
What effects does thyroxine have on the sympathetic nervous system?
Describe the presentation of a pt with hyperthyroidism?
*Weight loss despite increased appetite
*Breathlessness
*palpitations, tachycardia
*Sweating
*Heat intolerance
*Diarrhoea
*Lid lag and other sympathetic features
How do we diagnose and treat a thyroid storm?
- Medical emergency : 50% mortality untreated
- Blood results confirm hyperthyroidism
What is a thyroid storm characterised by?
What are the 3 treatment options for hyperthyroidism?
- surgery
- radioiodine
- drugs
What are the 4 classes of drugs used to treat hyperthyroidism?
- The thionamides (thiourylenes; anti-thyroid drugs)
- propylthiouracil (PTU)
- carbimazole (CBZ) - Potassium Iodide
- Radioiodine
- β-blockers
What effect does Potassium iodide bring about in regards to hyperthyroidism?
Wolff-Chakoff effect
Name 2 thionamides and what conditions we can use this drug to treat.
propylthiouracil
carbimazole
Graves’
Toxic thyroid nodule/toxic multinodular goitre
Describe the synthesis of thyroid hormone.
- Iodine is transported into the follicular cell via NaI co-transporter (I, 2Na)
- Na transported back out via NaKATPase
- I- transported across apical membrane into colloid
- Thyroperoxidase iodises tyrosine residues of thyroglobulin, making MIT and DIT.
- coupling reaction maing T3, rT3, T4
- Iodinated thyroperoxidase endocytoses back into follicular cell
- peroxidases cleave the T3 and T4
- exocytoses back into circulation
