MEH - Thyroid Dysfunction Flashcards
Where does the word ‘thyroid’ come from?
Greek “oval shield”
Should a normal thyroid be felt on examination?
Nope
What is the pre-tracheal fascia?
This attaches the thyroid gland to the trachea and larynx, meaning that the thyroid moves upwards on swallowing
Describe briefly the embryology of the thyroid gland
It forms initially under the tongue, and is connected to the skin by the thyroglossal duct. It then moves down past the hyoid bone to in front of the larynx, and the thyroglossal duct closes up
What is a thyroglossal duct cyst?
The thyroglossal duct usually disappears, but it may remain and form a cyst. It will always be in the anterior part of the midline of the neck. When tongue poked out, it will be drawn in
Why can TSH levels be used as an effective screening test for hyper/hypothyroidism?
Very rare for pituitary adenoma to produce TSH and cause thyrotoxicosis, so 98% of metabolic thyroid disease is due to primary abnormality of thyroid gland itself.
What does it suggest about thyroid function if TSH is raised?
Thyroid gland is underfunctioning (hypothyroidism)
What does it suggest about thyroid function if free T4 is increased?
It is over-functioning (hyperthyroidism)
Why is there a wide range of acceptable values for TRH, TSH and T4?
They are constantly responding to the environment
Are autoimmune endocrine diseases more common in women or men?
Women - we don’t know why
What are the three goitre structures?
- diffuse
- multinodular
- single nodule
Give three points in a woman’s life at which physiological goitre may occur
- menarche
- pregnancy
- menopause
How does iodine deficiency cause goitre?
Reduced thyroxine levels lead to increased TSH, which causes generalised thyroid enlargement, usually nodular
What is multinodular goitre?
Condition of unknown cause which affects 5% of western populations. Normal thyroid function at first, although after many years some may develop hyperthyroidism
What would be the symptoms in a child with iodine deficiency?
- intellectual disability
- abnormal gait
- deaf-mutism
- short stature
- goitre
- hypothyroidism