Thyrotoxicosis (E&M) Flashcards
Define thyrotoxicosis.
Symptoms caused by excessive circulation of thyroid hormones
Caused by conditions that lead to hyperthyroidism
What are some causes of thyrotoxicosis? (6)
- Grave’s disease
- toxic multinodular goitre (Plummer’s)
- toxic adenoma
- malignancy
- amiodarone-induced
- thyroiditis - de Quervain’s, postpartum, drug-induced, acute/infectious
What groups does thyrotoxicosis happen more commonly in? (2)
- F>M
- Grave’s disease present at 20-30y
What is Grave’s disease?
Presence of TSH-Rc stimulating autoantibodies –> hyperthyroidism due to loss of negative feedback
Absence of eye signs does not exclude diagnosis
What are some types of thyroid malignancy causing thyrotoxicosis? (5)
- papillary (60%)
- follicular (25%)
- medullary (5%)
- lymphoma (5%)
- anaplastic (rare)
What is de Quervain’s thyroiditis?
Viral thyroiditis - painful dysphagia and pyrexia
Hyperthyroid –> hypothyroid –> euthyroid
What is a thyroid storm?
Acute exacerbation of hyperthyroidism that results in a life-threatening hypermetabolic state
What may a thyroid storm be triggered by? (3)
- surgery
- trauma
- infection
What type of diabetes can trigger thyroid storm?
T1DM - DKA as it is acute stress on body
What are the clinical features of a thyroid storm? (6)
- hyperpyrexia >41C
- hypertension
- tachycardia
- jaundice
- severe N&V
- confusion and agitation/syncope
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
What is the most common cause of hyperthyroidism in countries with sufficient iodine intake?
Grave’s disease
What are the clinical features of general hyperthyroidism? (14)
- 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)
What are some Grave’s disease specific clinical features? (3)
- exophthalmos
- pretibial myxoedema
- thyroid acropachy - clubbing of fingernails
What are the two kinds of goitre (enlarged thyroid)?
- 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
What are some risk factors for hyperthyroidism? (7)
- Fx autoimmune thyroid disease
- female sex
- tobacco use
- high iodine intake
- lithium therapy
- radiation
- stress
What are the first-line investigations for hyperthyroidism? (6)
- 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
What would TFTs show in primary hyperthyroidism?
- high T3/T4
- low TSH
If anti-TSH receptor antibody is present, what does it mean?
Grave’s disease
(anti-TSH receptor antibodies very sensitive and specific for Grave’s)
(anti-TPO positive in 70%)
What does diffuse uptake throughout enlarged gland on radioactive iodine uptake scan mean?
Grave’s disease
What does multinodular gland with single hot nodule, patchy uptake on radioactive iodine uptake scan mean?
Toxic multinodular goitre
Treated with radioiodine therapy
What does diffuse uptake with single cold nodule on radioactive iodine uptake scan mean?
Thyroid cancer
What does no uptake on radioactive iodine uptake scan mean?
de Quervain’s (viral) thyroiditis
Or other thyroiditis (drug-induced, postpartum etc)
What is the disease course and presentation of de Quervain’s viral thyroiditis like?
Initially hyperthyroid and have painful tender goitre and dysphagia after a viral (flu-like) illness, then hypothyroid after, then resolves –> euthyroid
How is de Quervain’s (viral) thyroiditis managed?
Self-limiting, and can be managed conservatively e.g. NSAIDs
How do thyroid cancers show up on scintigraphy?
Cold spots
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
How do we manage symptoms in hyperthyroidism?
Propranolol (beta blocker) - for tachycardia and tremor
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)
What is the first-line management for Grave’s disease?
Carbimazole (inhibits TPO) - give for 12-18 months then reassess
When is carbimazole (anti-thyroid drug for Grave’s) contraindicated?
Early pregnancy
When is propylthiouracil the treatment of choice for Grave’s disease? (2)
- first trimester pregnancy
- thyroid storm
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
When do we do radioactive iodine ablation for hyperthyroidism?
If resistant to anti-thyroid drugs
Also for toxic multinodular goitre
What 2 conditions is radioactive iodine ablation the definitive treatment for?
- Grave’s disease
- toxic multinodular goitre
What do patients need to know about radioactive iodine ablation?
- cannot conceive for 6 months
- avoid contact with pregnant women or children
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
How do we treat toxic multinodular goitre?
Radioiodine therapy
How is de Quervain’s (viral) thyroiditis managed?
Self-limiting, and can be managed conservatively e.g. NSAIDs
When is potassium iodide used in hyperthyroidism?
Thyroid storm
Shrink thyroid prior to surgery
What are some complications of hyperthyroidism? (5)
- high output cardiac failure
- AF
- sight-threatening complications of Grave’s orbitopathy
- hyperlipidaemia
- myxoedema coma
What can thyroid hormone over-replacement lead to?
Bone loss and tachycardia
