Hypo + Hyperthyroidism Flashcards
What are the TSH and T4 levels in Graves Disease?
TSH low
T4 high
What are the TSH and T4 levels in primary hypothyroidism?
TSH high
T4 low
What is the TSH and T4 levels in primary hyperthyroidism?
TSH low
T4 high
What is the TSH and T4 levels in secondary hyperthyroidism?
TSH high
T4 high
What is the TSH and T4 levels in secondary hypothyroidism?
TSH low
T4 low
Which antibodies are responsible for Graves’ disease?
TSH receptor antibodies
Which conditions have anti-tpo antibodies? (2)
Graves’ disease
Hashimotos thyroiditis
Which 3 conditions have anti-tg antibodies?
Graves
Hashimotos
Thyroid camcer
Which 2 antibodies are present in Hashimotos thyroiditis?
Anti-tpo
Anti-tg
Diffuse high uptake is seen on radioactive iodine scan. What does this suggest?
Graves
Focal high uptake is seen on a radioactive iodine scan. What does this suggest?(2)
Toxic multinodulae goitre
Adenomas
Cold areas are seen on a radioactive iodine scan. What does this suggest?
Thyroid cancer
What is secondary hyperthyroidism usually caused by?
Pituitary adenoma
What is sub clinical hyperthyroidism?
where the thyroid hormones (T3 and T4) are normal and thyroid-stimulating hormone (TSH) is suppressed (low). There may be absent or mild symptoms.
What are the causes of hyperthyroidism? (4)
GIST
• G – Graves’ disease • I – Inflammation (thyroiditis) • S – Solitary toxic thyroid nodule • T – Toxic multinodular goitre
What are 4 types of thyroiditis?
○ De Quervain’s thyroiditis
○ Hashimoto’s thyroiditis
○ Postpartum thyroiditis
○ Drug-induced thyroiditis
What type of thyroidism does thyroiditis cause?
Initial period of hyperthyroidism
Followed by hypothyroidism
What are the nodules in solitary toxic thyroid nodules usually?
Benign adenoma
When is toxic multinodular goitre most common?
Over 50 yo
In what conditions is thyroid function regularly tested in? (4)
○ Type 1 diabetes
○ Other autoimmune disease
○ New onset AF
○ Depression and anxiety
What triad of symptoms is seen in thyroid storm?
Fever
Tachycardia
Delirium
What management is used in thyroid storm? (5)
• Beta blockers, anti-arrhythmics
• Fluids
• Thioamides = typically propylthiouracil, which has antithyroid effects and reduces conversion of T4 to T3
• Corticosteroids = reduce conversion of T4 to T3
• Lugol’s iodine
What is Lugols iodine and when is it typically used?
Aqueous iodine oral solution
Usually 4hrs after anti thyroid therapy in a thyroid storm
What are some symptoms of hyperthyroidism? (15)
• Anxiety and irritability
• Sweating and heat intolerance
• Tachycardia
• Weight loss
• Fatigue
• Insomnia
• Frequent loose stools - diarrhoea
• Sexual dysfunction
• Brisk reflexes on examination
• Fine tremor
• Palpitations
• Amenorrhoea
• Gynaecomastia (in men)
• Change in mood
Hair loss
What is pretibial myxoedema and when is it seen?
○ a skin condition caused by deposits of glycosaminoglycans under the skin on the anterior aspect of the leg (the pre-tibial area). It gives the skin a discoloured, waxy, oedematous appearance over this area. It is specific to Grave’s disease and is a reaction to TSH receptor antibodies.
What signs are seen specifically in Graves’ disease?
Exophthalmus
Pretibial myxoedema
Thyroid acropachy (hand swelling and finger clubbing)
Thyroid bruit
What is the first line treatment of hyperthyroidism?
Carbimazole
What are the 2 regimes available for Carbimazole?
• Block and replace = give at sufficient levels to block endogenous T3/T4 then give levothyroxine
• Dose titration = given alone, then dose adjusted to give normal levels of TSH
What is a side effect of Carbimazole? What is a side effect of propylthiouracil? And what is a side effect of both of these drugs?
Carbimazole = pancreatitis
Propylthiouracil = severe liver reactions
Both = agranulocytosis (look out for sore throat)
When is propylthiouracil used instead of Carbimazole? (3)
○ Intolerant/allergic to carbimazole
○ Pregnant/planning on pregnancy in 6months
○ A history of pancreatitis
What are the rules for radioactive iodine treatment? (3)
• Women must not be pregnant or breastfeeding and must not get pregnant within 6 months of treatment
• Men must not father children within 4 months of treatment
• Limit contact with people after the dose, particularly children and pregnant women
What is a side effect of radioactive iodine treatment for hyperthyroidism?
Hypothyroidism - need levothyroxine
What is used to manage symptoms of hyperthyroidism?
Beta blockers
Usually propranolol as it’s non selective
What are some complications of a thyroidectomy? (3)
Hypothyroidism
Hypocalcaemia as can get parathyroid glands on accident
Recurrent laryngeal nerve injury - hoarse voice
What is primary hypothyroidism?
Primary hypothyroidism = thyroid behaves abnormally and produces inadequate thyroid hormones. Negative feedback is absent, resulting in increased production of TSH. TSH is raised, and T3 and T4 are low.
What is secondary hypothyroidism?
Secondary hypothyroidism (central hypothyroidism) = where the pituitary behaves abnormally and produces inadequate TSH, resulting in under-stimulation of the thyroid gland and insufficient thyroid hormones. TSH, T3 and T4 will all be low.
What is the most common cause of hypothyroidism in the developed world? Developing world?
Developed = Hashimotos thyroiditis
Developing = iodine deficiency
What 2 drugs can cause hypothyroidism?
Lithium - inhibits thyroid hormone production
Amiodarone
What are some causes of secondary hypothyroidism? (5)
• Tumours (e.g., pituitary adenomas)
• Surgery to the pituitary
• Radiotherapy
• Sheehan’s syndrome (where major post-partum haemorrhage causes avascular necrosis of the pituitary gland)
• Trauma
What is Sheehan’s syndrome?
where major post-partum haemorrhage causes avascular necrosis of the pituitary gland
What are some symptoms of hypothyroidism? (10)
• Weight gain
• Fatigue
• Dry skin
• Coarse hair and hair loss
• Fluid retention (including oedema, pleural effusions and ascites)
• Heavy or irregular periods
• Constipation
• Cold intolerance
• Menstrual irregularities
• Reduced libido
What are some signs of hypothyroidism?(6)
• Hair loss (particularly the outer 3rd of eyebrow)
• Dry skin
• Goitre
• Bradycardia
• Myxoedema
• Delayed relaxation phase of deep tendon reflexes
What is the management of hypothyroidism?
Oral levothyroxine is the mainstay of treatment of hypothyroidism. Levothyroxine is a synthetic version of T4 and metabolises to T3 in the body.
What is TSH result if the levothyroxine dose is too high? Too low?
Too high = TSH will be low
Too low = TSH will be high
What can be used if levothyroxine is not tolerated?
Liothyronine sodium is a synthetic version of T3 and is very rarely used under specialist care where levothyroxine is not tolerated.
What is the presentation of myxoedema coma? (4)
○ Hypotensive
○ Hypothermic
○ Bradycardic
○ Cognitive decline
What is the management of myxoedema coma? (3)
○ IV levothyroxine
○ Electrolyte imbalances and hypothermia should be addressed
○ IV hydrocortisone may be needed unless hypopituitarism is ruled out as cause
What is the triad of signs for Hashimotos thyroiditis?
Hypothyroidism
Goitre
Anti-tpo
What chromosomes are associated with Hashimotos thyroiditis?
2 and 8
What are the 3 phases of de quervains thyroiditis?
• Thyrotoxicosis
• Hypothyroidism
• Return to normal
What is the management of de quervains thyroiditis? (3)
It is a self-limiting condition, and supportive treatment is usually all that is necessary. This may involve:
• NSAIDs for symptoms of pain and inflammation
• Beta blockers for the symptoms of hyperthyroidism
• Levothyroxine for the symptoms of hypothyroidism
