Hyperthyroidism (Thyrotoxicosis) Flashcards
Graves, subclinical hyperthyroidism, Thyroid storm, De Quervain's thyroiditis
What is thyrotoxicosis?
Thyrotoxicosis is the clinical, physiological, and biochemical state that occurs when tissues are exposed to excess thyroid hormone
What is the difference between hyperthyroidism and thyrotoxicosis?
Hyperthyroidism refers to the condition where there is an overactivity of the thyroid gland, leading to thyrotoxicosis.
Thyrotoxicosis is the result of excess thyroid hormones in the tissues, regardless of the cause
What is the most common cause of hyperthyroidism?
Graves disease
What is Graves’ disease, and what is its pathophysiology?
Graves’ disease is an autoimmune disorder where IgG antibodies stimulate the TSH receptors on the thyroid gland, causing overproduction of thyroid hormones (T3 and T4), resulting in hyperthyroidism
What is the primary difference between primary and secondary hyperthyroidism in terms of TSH and T3/T4 levels?
Primary hyperthyroidism
= ↓ TSH ↑ Free T3/T4
due to thyroid overproduction
Secondary hyperthyroidism
= ↑ TSH ↑ or normal Free T3/T4
due to excessive TSH stimulation
What are the general symptoms of hyperthyroidism?
(1) Weight loss despite increased appetite
(2) Frequent, loose bowel movements
(3) Sweating and heat intolerance
(4) Goitre
(5) Tremors, muscle weakness
(6) Sleep disturbances
(7) Anxiety, and depression
If the goitre is tender and painful. What does this mean?
Suggests de Quervain’s thyroiditis
= an inflammation of the thyroid often following a viral infection
What is the triad of Graves’ disease?
- Hyperthyroidism
- Ophthalmopathy (exophthalmos)
- Dermopathy (pretibial myxoedema)
What is Graves’ ophthalmopathy?
Eye changes like
(1) upper eyelid retraction
(2) lid lag
(3) exophthalmos
What is pretibial myxoedema?
Swelling on the shins
What are the common thyroid autoantibodies in Graves’ disease?
(1) Anti-TPO
(2) Anti-thyroglobulin
(3) TSH receptor antibodies
What are the thyroid hormone levels in primary hyperthyroidism?
↓ TSH, ↑ Free T3/T4
What are the thyroid hormone levels in secondary hyperthyroidism?
↑ TSH, ↑ or normal Free T3/T4
What is Exophthalmos?
buldging eyes
What are the most common investigations for diagnosing hyperthyroidism?
Thyroid function tests
Thyroid autoantibodies
When shouldn’t you check thyroid hormones
Dont check when sick (pneumonia etc) as levels will be wrong
What is the appearance of graves disease like?
smooth symmetrical goitre, looks like butterfly
What is the 1st line treatment for graves disease and its function?
Carbimazole
= Inhibits thyroid peroxidase
What is the 1st line treatment for graves disease if you’re in 1st trimester pregnancy?
PTU (Propylthiouracil)
What is the role of β-blockers in hyperthyroidism treatment?
Provide symptomatic relief
(e.g., anxiety, tremors)
treatment of thryotoxicosis!!!
What is the management for Graves’ eye disease?
Mild cases
= Topical lubricants
Severe cases
= Steroids, radiotherapy, or surgery
When is Radioiodine used?
- Completely or partially destroy thyroid function
- 1st choice treatment for relapsed Graves’ disease and nodular thyroid disease
- High risk of hypothyroidism when used in Graves’ disease
when is thyroidectomy used?
Useful when radioiodine is contraindicated in pregnancy but will leave a scar
What are the potential complications of thyroidectomy?
(1) Recurrent laryngeal nerve palsy (hoarseness)
(2) Hypothyroidism
(from removal of thyroid tissue)
(3) Hypoparathyroidism
(due to parathyroid gland damage)
What is the management of graves’ disease in order?
(1) Carbimazole
(1) If 1st trimester pregnancy
= PTU (Propylthiouracil)
(3) Radioiodine
1st choice treatment for relapsed Graves’ disease and nodular thyroid disease
(4) Thyroidectomy
= Used if radioiodine is contraindicated in pregnancy or above treatments not effective
How do you manage subclinical hyperthyroidism?
Subclinical hyperthyroidism is characterised by a
(1) suppressed TSH level
(2) with normal T3/T4 levels
Management is usually observational
What is a thyroid storm
Thyroid storm is a life-threatening complication with
(1) hyperpyrexia
(2) severe tachycardia
(3) restlessness
(4) cardiac failure
(5) liver dysfunction
What is the mangement for a thyroid storm?
- High dose propylthiouracil (PTU)
- Beta-blockers (eg, propranolol)
- Potassium iodide and hydrocortisone
- IV fluids and possibly inotropes
- Treat the underlying cause
How long does it generally take for the thyroid blood test results to change following a change in therapy?
6-8 weeks, given the long half life of T4
What pattern of thyroid blood tests would you expect in subclinical hyperthyroidism?
- Low/suppressed TSH
- Upper normal range T3 and T4
Where is the best place to manage a patient with a thyroid storm?
HDU / ITU
What pattern of thyroid function tests would you expect with Grave’s disease?
- Elevated T3 and T4
- low or suppressed TSH
What is the role of steroids in a thyroid storm?
To block the conversion of T4 to T3
What should a patient on Carbimazole do when they notice a sore throat?
Stop taking medication and get an urgent blood test
What is the main side effect / symptom to warn patients on anti-thyroid medication about?
Sore throat/ Agranulocytosis
What is the treatment
(other than thyroid blocking medications)
available to people with subclinical hyperthyroidism and complications such AF or Osteoporosis?
Ablation therapy
A 42-year-old woman is seen in the thyroid clinic for her Graves’ disease. She complains of eye discomfort and grittiness. The endocrinologist suggests some lifestyle changes.
Which of the following is a complication of thyroid eye disease?
A. Anterior uveitis
B. Optic neuropathy
C. Optic neuritis
D. Blepharospasm
E. Enophthalmos
Explain why?
B - Optic neuropathy
= can lead to vision loss
A 34-year-old woman presented with anxiety and palpitations.
Examination showed a bilateral tremor in her hands and diffuse eye lid retraction with some periorbital swelling. There was also a non-tender mass in the anterior midline of the neck.
Which blood test is most likely abnormal in this condition?
Thyroid-stimulating immunoglobulin
When would ‘De Quervain’s thyroiditis’ be the most likely diagnosis?
(1) Tender goitre
(2) Symptoms of thyrotoxicosis
= weight loss, sweating, palpitations, tremors
(3) Low TSH, low free T4
= initial hyperthyroid phase
(4) Can progress to hypothyroidism
What is the hallmark feature of
De Quervain’s thyroiditis?
tender goitre (painful thyroid gland)
= often associated with a recent viral infection
A 40-year-old woman with known Grave’s disease has been unwell over the past week with a severe chest infection. She had recently been started on treatment with Carbimazole.
She is also experiencing agitation, confusion, fevers, palpitations, tachycardia, and vomiting.
On examination, she is jaundiced, clinically dehydrated and auscultation of the chest reveals bibasal crackles.
What is the most likely diagnosis?
Thyroid storm
A 40-year-old man presents with weight loss, increased appetite and anxiety. On examination, he has exophthalmos.
What laboratory finding would best support the most likely underlying diagnosis?
TSH receptor-stimulating antibodies
What are the main complications of hyperthyroidism?
- Atrial fibrillation
- HF
- Osteoporosis
- Thyroid storm
- Graves’ ophthalmopathy
= Eye problems like exophthalmos and vision loss - Myopathy
What is a toxic Multinodular Goitre?
Occurs in those >50 with numerous firm nodules in the goitre
A 25-year-old woman presents to primary care two months after the delivery of her healthy second child. She reports that she has been having a lot of anxiety in the last two weeks, with increasing intensity and duration. She has also been struggling to sleep much more than after her first birth and has lost a significant amount of weight over the last few weeks. On examination, she has a fine tremor and her heart rate is elevated at 94. Her past medical history is significant for T1DM which is well controlled. She has chosen not to breastfeed.
Given the likely diagnosis, which of the following treatment options is most appropriate?
Propranolol
When is propranolol combined with carbimazole in hyperthyroidism treatment?
When rapid symptom control
(eg, tachycardia, tremors, anxiety, palpitations)
is needed alongside thyroid hormone reduction
A 30 year old woman arrives at her General Practitioners with a 2 month history of a painless fullness in the neck, tachycardia and a rash on the anterior aspects of both lower legs. On examination, she has a fine tremor and a diffuse goitre
What is the most likely cause of the patient’s symptoms?
Graves disease
A 28-year-old woman has a background of Grave’s disease and is on treatment with carbimazole. She has presented to the Emergency Department with a flu-like illness and fever
What is the most important initial blood test?
FBC
Subclinical hyperthyroidism is diagnosed. What is the next best step?
Repeat thyroid function tests in 3–6 months
A 36-year-old man presents following some routine blood tests which reveal
(1) thyroid-stimulating hormone (TSH) level of 0.1 mIU/L
(reference range: 0.4-4.0 mIU/L)
(2) normal free thyroxine (T4) level
He is otherwise well in himself and physical examination is unremarkable.
What is the most likely diagnosis based on these findings? and explain why
Subclinical hyperthyroidism
= decreased TSH level with normal free T4 levels
Why is Propylthiouracil (PTU) preferred over carbimazole in the management of thyroid storm?
PTU is preferred in thyroid storm because it inhibits both thyroid hormone synthesis and the conversion of T4 to T3, which is essential for rapid management
What would a thyroid function test look like in a person who had a thyroid storm complication?
Elevated T3 + T4
Low TSH
Contraindications for Radioactive Iodine Treatment include what?
- Pregnancy
- Graves’ ophthalmopathy
- Thyroid storm)
- Breastfeeding
- Young children
A 37-year-old woman presents with sweating, palpitations, tachycardia and acute confusion.
On examination she is warm to touch, has an irregular pulse, a heaving apex, evidence of pulmonary oedema and a smooth symmetrical swelling of the anterior neck.
What is the most appropriate initial management of this patient?
IV propanolol
What is the management for thyrotoxic storm in order?
Symptom control =
(1) IV propanolol
(2) IV digoxin if propanolol is contraindicated (e.g. asthma, low BP)
Reduce thyroid activity =
(1) Propylthiouracil
(2) Lugol’s iodine (administered 4 hours after propylthiouracil)
(3) IV hydrocortisone
A 30-year-old female presents to the emergency department with a one-day history of nausea, abdominal pain and confusion. She has a past medical history of hyperthyroidism and is currently five months pregnant. Her husband says that recently she has not been very compliant with her medications and stopped taking them altogether a few days ago.
Observations show a heart rate of 150, blood pressure of 135/80 and a temperature of 38.8 degrees. The patient has a set of blood tests which show very high T3 and T4 levels and a low TSH. Her other blood tests including inflammatory markers are normal.
Based on the presentation and the deranged thyroid function tests, the patient is diagnosed with a thyrotoxic storm.
What is the most appropriate antithyroid medication to prescribe? and explain why it isn’t propylthiouracil???
Carbimazole
= Carbimazole is to treat a thyrotoxic storm after 16 weeks gestation whereas propylthiouracil is to treat a thyrotoxic storm during the first 16 weeks of gestation
What is the difference between Subclinical hypothyroidism and Subclinical hyperthyroidism?
hypothyroidism = ↑TSH, normal fT4/3
hyperthyroidism = ↓TSH, normal fT4/3
A 45-year-old female presented with symptoms of tremor, palpitations and weight loss. On assessment by her doctor there appeared to be neck swelling. Upon investigation by an ultrasound scan, a toxic multinodular goitre was demonstrated.
What would nuclear scintigraphy show in this case?
Patchy uptake
A 45-year-old female is being seen in the endocrinology clinic. She was referred to following complaints over the past month of always feeling very hot, sweating constantly and experiencing palpitations. The endocrinologist had requested blood tests to investigate the underlying cause.
(1) Thyroid-stimulating hormone
(TSH) 0.2 mU/L (0.5-5.5)
(2) Free thyroxine
(T4) 34 pmol/L (9.0 - 18)
(3) TSH receptor stimulating antibodies = Positive
What further findings would support the likely diagnosis?
Pretibial myxoedema
Exophthalmos is a specific feature of what? and what does it associate with?
Exophthalmos is a specific feature of Grave’s disease rather than generic hyperthyroidism
= Diplopia and eye pain
“Antibodies stimulating the thyroid-stimulating hormone receptor”
What does this describe?
Graves disease
A patient with toxic multinodular goitre (TMNG) presents with nodular neck swelling and patchy uptake on nuclear scintigraphy, confirming the diagnosis. What is the correct first-line treatment?
Radioactive iodine therapy
De Quervain’s thyroiditis other name
Subacute
What are the four phases of subacute thyroiditis?
- Hyperthyroid phase (3–6 weeks)
= Painful goitre, raised ESR - Euthyroid phase (1–3 weeks)
- Hypothyroid phase
= weeks to months - Recovery phase
= Thyroid function normalises
What is a key finding on thyroid scintigraphy in subacute thyroiditis?
Globally reduced uptake of iodine-131, indicating thyroid inflammation and hormone leakage
During which phase of subacute thyroiditis does hypothyroidism occur?
Phase 3
In a thyroid storm, should PTU or a β-blocker be given first?
Both are given, but PTU is given first if the patient is haemodynamically stable, while a β-blocker is given first if there is life-threatening tachycardia or arrhythmias
What antibody is most commonly associated with Graves disease?
TSH receptor stimulating antibodies
A 58-year-old woman presents to the emergency department with confusion. She is found to have a raised temperature, tachycardia and is hypotensive. After further investigation, she is found to be in a thyrotoxic storm.
Given her presentation what is the best first-line treatment?
Beta-blockers, propylthiouracil and hydrocortisone
= mentions hypotension so hydrocortisone is given too
A 55-year-old female presented with frequent sweating, palpitations and diarrhoea. She also reported losing 3 kilograms over the past month. She has a history of atrial fibrillation.
What is the most likely cardiac sequela of her condition?
High output cardiac failure
Nuclear scintigraphy shows diffusely and increased activity with a decreased background. What does this suggest?
Graves Disease
A 65-year-old man is brought to the emergency department. Collateral history reveals two days of worsening shortness of breath, cough, and green, purulent sputum. Since these symptoms began, he has also become increasingly confused.
He has a history of paroxysmal atrial fibrillation (AF), Grave’s disease and hypertension.
His temperature is 42ºC, blood pressure is 176/95mmHg, heart rate is 140 beats per minute, respiratory rate is 31 breaths per minute and oxygen saturation is 95% on room air. On examination, his hands are sweaty and his pulse is irregularly irregular.
(1) What is the above describing and how do you know?
(2) What is the definite management for this condition?
(1) Thyroid storm
- Fever (42ºC)
- Tachycardia (140 bpm)
- Irregularly irregular pulse - Suggests atrial fibrillation
- Confusion
- Increased respiratory rate (31 bpm) and worsening shortness of breath
(2) beta-blockers, propylthiouracil and hydrocortisone
What drugs precipitate agranulocytosis?
Both Carbimazole and PTU
A patient presents with postpartum thyroiditis. Her Blood results show: Increased T3 + T4
Decreased TSH
What is the most appropriate treatment?
Propranolol
A 43-year-old female has been diagnosed with Grave’s disease, her most prominent symptoms include; weight loss, heat intolerance and a tremor, the latter of which is impacting her work as a waitress. The doctor has started her on a course of carbimazole for Grave’s disease but after 3 days she is dissatisfied with the effects, what else could she be prescribed for symptom control?
Beta-blockers
A 26-year-old female attends an outpatient appointment having recently been diagnosed with Grave’s disease. This is typically characterised by three unique signs. Along with thyroid eye disease, what other signs are they?
Thyroid acropachy & pretibial myxoedema
