Flashcards in Thyroid diseases Deck (31)
4 main Thyroid function tests
TSH [most influential]
- Low= hyperthyroidism, secondary hypothyroidism
- High= Primary hypothyroidism
Used to measure thyroid functioning.
- Anti-thyroid peroxidase
- TSH receptor antibody [TRAB]
TSH receptor antibodies
Antibodies directed against the TSH receptor
- Can stimulate or block the receptor
Amount is measured to assess function of the thyroid.
- Blocking TRAb= hypothyrodism, such as Hashimoto's
- Stimulating TRAb= Graves'
Anti-thyroid peroxidase antibody
- Raise antibodies indicate...
Antibodies that target thyroid peroxidase
Thyroid peroxidase enzyme facilitates the addition of iodine into thyroglobulin.
Raised antibodies indicate
- Graves' disease
- Hashimoto's thyroiditis
- Nodular goitre
- Thyroid carcinoma
Causes of hyperthyroidism 
Autoimmune [Graves' disease]
Toxic multinodular goitre
Hyperthyroidism symptoms 
High temperature/ Heat intolerance
Increased sweating, thirst
Sweaty, moist skin
Goitre with bruit
Ophthalmoplegia [muscle paralysis around the eye]
- Most common cause of hyperthyroidism
- Mainly in women, 30-50 yrs
- Thyroid eye disease [20%]
- Goitre with bruit
- Family history of thyroid/ endocrine disease
- TSH receptors are overstimulated in the thyroid [high TSH-receptor antibody].
Investigating Graves' disease
Prevalence of thyroid autoantibodies.
Thyroid uptake scan will show diffuse distribution.
Thyroid function results
- Low TSH
- High FT4, FT3
Graves' disease medical treatment
Dosage can start high then get titrated down.
- High dose maintained whilst administering thyroxine.
- 1/3 cured
- The rest relapse
- Used to treat hyperthyroidism
- Kills thyroid cells
- Close contact with others
- Contraindicated in thyroid eye disease
- Pregnancy [4-6 months wait at least]
- Airport security
Surgery that partial removes the thyroid
- Treats hyperthyroidism [Graves]
Requires medical therapy
- Must be euthyroid before surgery
- Neck scar
- Hypothyroidism [thyroid hormones given life-long]
- Vocal cord palsy.
Placental beta-human chorionic gonadotrophin [hCG] is released in the first trimester.
- hCG has similiar structure to TSH
- Reduces TSH levels and stimulates thyroid hormone productions
Hyperthyroidism risk increases when
- Pregnant with twins
- Has severe hyperemesis
Thyroid eye disease
Autoimmune condition that targets orbital tissue around the eyes
- Especially extra-ocular muscles.
Mainly associated with Graves' disease
- Confirmatory feature.
Thyroid eye disease
- Presentation 
- Protrusion of the eyes
- Can cause inability to close eyes and lead to ulcerated corneas
Itchy/ dry eyes
Compression of the optic nerve can lead to colour blindness
Inflammation of the conjuctiva
Thyroid eye disease treatment 
- IV methylprednisolone
- Oral prednisolone
- Relieve compression
Benign tumour of the thyroid that can secrete excess T3
- Causing hyperthyroidism
- Cancer must be excluded
- Fine needle-aspiration biopsy
- Short term medical initially
Enlargement of thyroid due to iodine deficiency.
Thyroid enlarges to absorb more iodine.
Toxic multi-nodular goitre
Presence of multiple adenomas on the thyroid.
- Nodules can secrete excess thyroid hormones causing hyperthyroidism
Investigation will show thyroid uptake scan with patchy appearance.
- Uptake more [darker] in nodules.
- Initially medically, to control symptoms [beta-blockers]
- Curative= radioiodine.
A life-threatening increase in thyroid hormone effects.
- Incomplete hyperthyroidism treatment.
- Untreated hyperthyroidism
- High fever
- Arrhythmia, tachycardia
- Vomiting, diarrhoea
- Ionorganic iodine
- Anti-thyroid drugs [carbimazole, propylthiouracil]
- Beta blockers
- IV fluids
Triggers of thyroid storm 
Acute/ severe illness/ infection
Conditions associated with thyroid disease
- Autoimmune 
Other autoimmune conditions
- T1 diabetes
- Pernicious anaemia
- Addison's disease [hypoadrenalism]
- Premature ovarian failure
- Coeliac disease
- Symptoms 
Weight gain [despite no change in diet and physical activity]
- Signs 
Diffuse hair loss
Carpel tunnel [compression of the median nerve]
- attack on thyroid gland.
Autoimmune primary hypothyroidism
Most common cause of hypothyroidism.
Autoantibodies block TSH receptors
- Also inhibits peroxidase
- Reduced FT4, FT3, high levels of TSH.
Primary autoimmune hypothyroidism with the presence of goitre
- Contain lymphocytic infiltration
Autoimmune hypothyroidism without goitre or lymphocytic infiltration.
Caused by accumulation of glycosaminoglycans in interstitial.
Very severe, can lead to death/ coma
Self-limiting thyroid disease characterised by initial hyperthyroidism then hypothyroidism.
- Lasts 1-2months
- Does not respond to anti-thyroid drugs
- Cold isotope scan [uptake reduced]
Longer hypothyroid phase
- 4-6 months
- Mostly normal within a year