clinical thyroid disease - hypothyroidism Flashcards
What are the three main parts of the thyroid gland
Right lobe, left lobe and the isthmus
How is the release of T3 and T4 stimulated
TRH is released from the hypothalamus and travels to the anterior pituitary where it stimulates the release of TSH which then goes to the thyroid gland and stimulates the release of T3 and T4
What causes the negative feedback in the release of T3 and T4
T3 and T4 on the anterior pituitary and the hypothalamus
What is the normal TSH level
0.35-4.5
What are the symptoms of hypothyroidism
Fatigue/lethargy
Cold intolerance
weight gain
weakness, arthralgia and myalgia
constipation
irregularities in menstruation
depression
dry skin and reduced hair
thyroid pain
What are the signs of hypothyroidism that are seen on examination
Course dry skin/ hair and hair loss
Oedema including swelling of the eye balls and puffy face
Hoarseness in the voice or deepening
Goitre
Bradycardia and diastolic hypertension
Delayed relaxation of deep tendon reflexes
Paraesthesia caused by carpal tunnel
What is carpal tunnel syndrome
Pressure on the nerves in the wrist that can cause paraesthesia and numbness in the hands and fingertips
What tests are done for hypothyroidism suspicion
Bloods :
TFT - thyroid function tests - T4 and TSH
Full blood count
HbA1c - to check for diabetes
Which gender is hypothyroidism more common in
Women
What are the congenital causes of of hypithyroidism
Agenesis / maldevelopment
Issues with production of hormones
What is the most common cause of primary hypothyroidism
Hashimatos autoimmune thyroid disease
What drugs can cause primary hypothyroidism
Antithyroid drugs, amiodarone, lithium and interferon
What is the link between iodine and hypothyroidism
Chronic iodine deficiency can cause hypothyroidism - iodine is required for the production of T3 and T4
What are causes of secondary.tertiary hypothyroidism
Pituitary tumour
Craniopharyngioma
Post pituitary surgery or radiotheraoy
What is the treatment for hypothyroidism in adults less than 65
Start levothyroxine at 1.6micrograms per kg per day