Thyrotoxicosis (E&M) Flashcards

1
Q

Define thyrotoxicosis.

A

Symptoms caused by excessive circulation of thyroid hormones

Caused by conditions that lead to hyperthyroidism

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2
Q

What are some causes of thyrotoxicosis? (6)

A
  • Grave’s disease
  • toxic multinodular goitre (Plummer’s)
  • toxic adenoma
  • malignancy
  • amiodarone-induced
  • thyroiditis - de Quervain’s, postpartum, drug-induced, acute/infectious
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3
Q

What groups does thyrotoxicosis happen more commonly in? (2)

A
  • F>M
  • Grave’s disease present at 20-30y
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4
Q

What is Grave’s disease?

A

Presence of TSH-Rc stimulating autoantibodies –> hyperthyroidism due to loss of negative feedback

Absence of eye signs does not exclude diagnosis

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5
Q

What are some types of thyroid malignancy causing thyrotoxicosis? (5)

A
  • papillary (60%)
  • follicular (25%)
  • medullary (5%)
  • lymphoma (5%)
  • anaplastic (rare)
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6
Q

What is de Quervain’s thyroiditis?

A

Viral thyroiditis - painful dysphagia and pyrexia

Hyperthyroid –> hypothyroid –> euthyroid

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7
Q

What is a thyroid storm?

A

Acute exacerbation of hyperthyroidism that results in a life-threatening hypermetabolic state

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8
Q

What may a thyroid storm be triggered by? (3)

A
  • surgery
  • trauma
  • infection
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9
Q

What type of diabetes can trigger thyroid storm?

A

T1DM - DKA as it is acute stress on body

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10
Q

What are the clinical features of a thyroid storm? (6)

A
  • hyperpyrexia >41C
  • hypertension
  • tachycardia
  • jaundice
  • severe N&V
  • confusion and agitation/syncope
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11
Q

How do we manage a thyroid storm? (4)

A
  • high-dose propylthiouracil (followed by potassium iodide in the form of Lugol’s iodine 6h later)
  • hydrocortisone
  • IV propranolol
  • IV digoxin
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12
Q

What is the most common cause of hyperthyroidism in countries with sufficient iodine intake?

A

Grave’s disease

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13
Q

What are the clinical features of general hyperthyroidism? (14)

A
  • weight loss (despite increased appetite)
  • heat intolerance
  • palpitations
  • tachycardia
  • tremor
  • restlessness
  • anxiety
  • sweating
  • diarrhoea
  • oligo/amenorrhoea
  • loss of libido
  • hair thinning
  • onycholysis (nail separates from bed)
  • lid lag (eyelid lags behind eye’s descent as patient watches your finger descend)
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14
Q

What are some Grave’s disease specific clinical features? (3)

A
  • exophthalmos
  • pretibial myxoedema
  • thyroid acropachy - clubbing of fingernails
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15
Q

What are the two kinds of goitre (enlarged thyroid)?

A
  • diffuse goitre - autoimmune (Grave’s, Hashimoto’s), endemic (iodine deficiency), acute thyroiditis (de Quervain’s), physiological (pregnancy, puberty)
  • nodular goitre - multinodular (usually euthyroid), fibrotic goitre, solitary nodule, discrete nodule in MNG
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16
Q

What are some risk factors for hyperthyroidism? (7)

A
  • Fx autoimmune thyroid disease
  • female sex
  • tobacco use
  • high iodine intake
  • lithium therapy
  • radiation
  • stress
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17
Q

What are the first-line investigations for hyperthyroidism? (6)

A
  • TFTs - TSH, T3, T4
  • autoantibodies (anti-TSH receptor in Grave’s, anti-TPO in Hashimoto’s, anti-TG)
  • serum calcium
  • thyroid ultrasound
  • fine needle aspiration for neck lumps
  • radioactive iodine uptake scan
18
Q

What would TFTs show in primary hyperthyroidism?

A
  • high T3/T4
  • low TSH
19
Q

If anti-TSH receptor antibody is present, what does it mean?

A

Grave’s disease

(anti-TSH receptor antibodies very sensitive and specific for Grave’s)

(anti-TPO positive in 70%)

20
Q

What does diffuse uptake throughout enlarged gland on radioactive iodine uptake scan mean?

A

Grave’s disease

21
Q

What does multinodular gland with single hot nodule, patchy uptake on radioactive iodine uptake scan mean?

A

Toxic multinodular goitre

Treated with radioiodine therapy

22
Q

What does diffuse uptake with single cold nodule on radioactive iodine uptake scan mean?

A

Thyroid cancer

23
Q

What does no uptake on radioactive iodine uptake scan mean?

A

de Quervain’s (viral) thyroiditis

Or other thyroiditis (drug-induced, postpartum etc)

24
Q

What is the disease course and presentation of de Quervain’s viral thyroiditis like?

A

Initially hyperthyroid and have painful tender goitre and dysphagia after a viral (flu-like) illness, then hypothyroid after, then resolves –> euthyroid

25
How is de Quervain's (viral) thyroiditis managed?
Self-limiting, and can be managed conservatively e.g. NSAIDs
26
How do thyroid cancers show up on scintigraphy?
Cold spots
27
What are the different types of thyroid cancers? (5)
- papillary carcinoma - lymph node metastasis predominate - follicular adenoma - solitary thyroid nodules - follicular carcinoma - vascular / capsular invasion - medullary carcinoma - calcitonin raised, familial, lymphatic and haematogenous spread - anaplastic carcinoma - elderly females, local invasion, resection
28
How do we manage symptoms in hyperthyroidism?
Propranolol (beta blocker) - for tachycardia and tremor
29
What different definitive managements are there for hyperthyroidism? (3)
- anti-thyroid drugs - carbimazole (inhibits TPO), propylthiouracil, potassium iodide - radioactive iodine ablation - destruction of thyroid tissue via radioactive iodine - thyroid surgery (total thyroidectomy)
30
What is the first-line management for Grave's disease?
Carbimazole (inhibits TPO) - give for 12-18 months then reassess
31
When is carbimazole (anti-thyroid drug for Grave's) contraindicated?
Early pregnancy
32
When is propylthiouracil the treatment of choice for Grave's disease? (2)
- first trimester pregnancy - thyroid storm
33
What are some side effects of anti-thyroid drugs (carbimazole and propylthiouracil)?
Agranulocytosis + neutropenia- seek urgent medical attention if infection developed so FBC can be measured
34
When do we do radioactive iodine ablation for hyperthyroidism?
If resistant to anti-thyroid drugs | Also for toxic multinodular goitre
35
What 2 conditions is radioactive iodine ablation the definitive treatment for?
- Grave's disease - toxic multinodular goitre
36
What do patients need to know about radioactive iodine ablation?
- cannot conceive for 6 months - avoid contact with pregnant women or children
37
How do we manage a thyroid storm? (4)
- high-dose propylthiouracil (followed by potassium iodide in the form of Lugol's iodine 6h later) - hydrocortisone - IV propranolol - IV digoxin
38
How do we treat toxic multinodular goitre?
Radioiodine therapy
39
How is de Quervain's (viral) thyroiditis managed?
Self-limiting, and can be managed conservatively e.g. NSAIDs
40
When is potassium iodide used in hyperthyroidism?
Thyroid storm Shrink thyroid prior to surgery
41
What are some complications of hyperthyroidism? (5)
- high output cardiac failure - AF - sight-threatening complications of Grave's orbitopathy - hyperlipidaemia - myxoedema coma
42
What can thyroid hormone over-replacement lead to?
Bone loss and tachycardia