Clinical Spectrum of Thyroid Disorders

Question 1

Symptoms of hyperthyroidism

Answer 1

General: speeding up, heating, thinning
Intolerance to heat
Fine, straight hair
Bulging eyes
Enlarged thyroid
Tachycardia
Increase SBP
Breast enlargement
Weight loss
Muscle wasting
Leg edema
Amenorrhea
Diarrhea
Tremours
Clubbing

Question 2

3 main causes of acquired hyperthyroidism

Answer 2

Grave’s disease
Toxic “hot” autonomous nodules
Thyroiditis

Question 3

Grave’s disease

Answer 3

Spontaneous autoimmune disease
Can be rapid and severe
TSH receptor stimulating autoantibodies
Hyperplastic and hyperfunctioning thyroid

Question 4

3 possible manifestations specific to grave’s disease

Answer 4

Diffuse hypervascular goiter +/- bruit
Eye bulging (orbitopathy)
Pretibial myxedema

Question 5

Thyroiditis

Answer 5

Transient
Spontaneous inflammatory condition
Damage to thyroid follicles
Leak of thyroid hormone
Hyper then hypothyroid phases
On scan, will not see increased uptake (because its just leaking the preformed hormone
Evolves and resolves over 3 months
Anti-TPO Ab is often present

Question 6

Toxic “hot” autonomous nodule

Answer 6

Spontaneous, benign hyperplasia
Focal adenoma
Over-producing thyroid hormone without need of TSH stimulation (autonomous)
Often asymptomatic/subclinical
Treatment controversies

Question 7

What happens to the thyroid hormone in the first trimester? Why?

Answer 7

Physiological hyperthyroidism

hCG is a TSH analog, so stimulates extra maternal thyroid hormone production

Question 8

2 steps in the lab diagnosis of primary thyroid dysfunction

Answer 8

Step 1: TSH (it is THE screening test for primary!)
If TSH is abnormal
Step 2: Free T4 (+/- free T3)
For low TSH should expect either normal or high normal fT4 (subclincal hyperthyroidism) or high fT4 (or fT3) (overt hyperthyroidism)

Question 9

How does overt hyperthyroidism differ between young and old ages?

Answer 9

Young: hyperadrenergic picture predominates
Old: catabolic symptoms may predominant (depression, lethargic, wasting), “apathetic hyperthyroidism”, weight loss, tachy, risk fo afib

Question 10

Treatment of overt hypertyroidism

Answer 10

Beta block if sufficient symptoms and no contraindication
Temporary reduction: thyroid blocking agens, methimazole, PTU
Permanent: radioactive iodine therapy or thyroidectomy

Question 11

Symptoms of hypothyroidism

Answer 11

Wide variability
Genera; slowing, cooling and coarsening
Thinning hair and hair loss
\+/- enlarged thyroid
Puffy face
Dry and coarse skin
Constipation
Cool extremities and swelling of the limbs
Slow beartbeat
Poor appetite
Infertility, heavy menstruation
Carpal tunnel

Question 12

Hashimoto’s thyroiditis

Answer 12

Acquired permanent hypothyroidism
Spontaneous
Slowly evolving
Antibodies against the thyroid gland lead to hypothyroidism (lymphocytic infiltration and destruction of gland)
Anti-TPO ab can be present but is non specific

Question 13

Postpartum thyroiditis

Answer 13

Onset 2-5 months post partum
Spontaneous but transient
Can be hyper and then hypothyroid or just hypo
Often depressed, fatigued, with poor concentration
Inflammation of the gland with release of thyroid hormone but no permanent damage

Question 14

Treatment of overty hypothyroidism

Answer 14

Hormone replacement with levothyroxine (synthetic T4)
Symptoms improve in 2-3 weeks
Recheck TSH in 2-3 months an then annually

Question 15

Fetus is dependent on maternal thyroid hormone until…

Answer 15

12-16 weeks gestation

Question 16

Iodine deficiency on fetus

Answer 16

Most common cause of preventable mental retardation