7. Thyroid disease- Hypothyroidism and Goitre Flashcards
what are hypothyroidism
term used to describe inadequate output of thyroid hormones by the thyroid gland
what is the most common cause of hypothyroidism
- in the developed world
- in the developing world
- Hashimoto’s thyroiditis
2. iodine deficiency
what is Hashimoto’s thyroiditis caused by
- autoimmune inflammation of the thyroid gland
- associated with antithyroid peroxidase (anti-TPO) antibodies and antithyroglobulin antibodies
- initially it causes a goitre after which there is atrophy of the gland
What are other causes of hypothyroidism
Hashimoto’s thyroiditis
iodine deficiency
all of the treatments for hyperthyroidism
name the common drugs that have the potential to cause hypothyroidism
carbimazole Propylthiouracil radioactive iodine thyroid surgery lithium amiodarone
what are the central causes of (secondary hypothyroidism) and why is it caused
pituitary gland fails to produce enough TSH
- associated with lack of other pituitary hormones such as ACTH
- tumours
- infection
- vascular
- radiation
what are the common symptoms of hypothyroidism
Cold intolerance
hoarse/deep voice
constipation
myalgia and muscle weakness
Weight gain fatigue/ lethargy dry skin coarse hair and hair loss fluid retentions (oedema, pleural effusion, ascites) heavy or irregular periods
What would primary hypothyroidism investigations show
- site of pathology
- TSH
- T3 and T4
- Thyroid glad
- high
- low
what would secondary hypothyroidism investigations show
- site of pathology
- TSH
- T3 and T4
- pituitary gland
- Low
- Low
What is the treatment for hypothyroidism
oral levothyroxine (synthetic T4)
- dose is titrated till normal TSH levels are normal
- if TSH levels are high then the dose is too low and needs to be increased
- if TSH is too low then the dose is too high and needs to be reduced
What is the normal formulation of thyroxine, how often is it given and what are the side effects
mostly 100-125 mcg per day
once daily
no side effects
monitor dose with TFT
why do you use T4 and not T3
T4 is produced 100 mcg a day
T3 is produced 30 mcg but 80% of this is made from T4-T3 conversion and only 20% is from thyroidal production
what can overdosing of thyroxine cause
AF or osteoporosis
If the patient still has symptoms of hypothyroidism then the dose should be increased by what increments
25 mcg steps
what kind of patients should be prescribed thyroxine at low dose of 25mcg and increased slowly every 4 week and why
elderly patients and those with known ischaemic heart disease
higher dose may worsen angina or precipitate myocardial infarction
which carcinoma of the thyroid is an inherited condition and is associated with adrenal tumour and hyperparathyroidism
medullary cell carcinoma
What are the other red flag symptoms if someone was to present with a lump in the throat
dysphagia neck pain hoarseness history of radiation to neck family history of thyroid cancer
how would you investigate a palpable goitre
carry out an ultrasound followed by a fine needle aspiration (FNA) of the lump
what are the most common types of thyroid carcinomas (cancer arising in the epithelial tissue of the skin or in the lining of internal organs)
o Papillary carcinoma 70% o Follicular carcinoma 20% o Anaplastic carcinoma 3% o Lymphoma 2% o Medullary cell carcinoma 5%
Where do medullary cell carcinomas usually arise from
the C cells in the thyroid
how do you usually treat thyroid cancer
with surgery (total thyroidectomy or lobectomy) post-operative radioactive iodine treatment (selected treatment) thyroid hormone suppression (to suppress TSH so that tumour growth is not stimulated
what is a goitre
simply means an enlarged thyroid
what diseases can cause a diffuse goitre
o Graves diseases
o Hypothyroidism (hashimoto)
o Colloid goitre (euthyroid)
o Iodine deficiency drugs (lithium etc)
are thyroid nodules common with age
yes they are
o 30-60% of normal thyroids have nodules at autopsy
