Graves' disease Flashcards
How can thyrotoxic storm manifest?
Abdominal pain
Infective colitis, or possibly pseudomembranous colitis, following antibiotic treatment should be considered and diabetic ketoacidosis can present with sweating, pyrexia and abdominal pain. Must also rule out acute pancreatitis/perforated viscus.
Which types of hyperthyroidism usually present with painful midline neck lump?
Hashimotos thyroiditis and de Quervain’s subacute thyroiditis are usually painful
How do beta blockers help with hyperthyroidism?
Beta blockers will inhibit peripheral conversion of T4 to T3 (active form).
True or false: In thyroid crisis you should do a radioisotope investigation of the thyroid urgently.
Radioiodine can precipitate/worsen thyroid crisis but can be useful for later management (possible focal hot nodule or diffuse uptake).
Which of these are triggers for a thyroid crisis?
- Thyroid surgery
- Infection
- Type 2 diabetes mellitus
- Myocardial infarction
- Diabetic ketoacidosis
- Radioactive iodine administration
- Hip replacement
- Thyroid surgery
- Infection
- Myocardial infarction
- Diabetic ketoacidosis
- Radioactive iodine administration
- Hip replacement
Type 2 diabetes has not been shown to be a precipitants of thyroid crisis but the type 1 diabetes complication DKA does.
Name some eye signs of thyroid disease.
proptosis and conjunctival oedema
Which of these are symptoms of thyrotoxicosis?
- Anorexia (loss of appetite)
- Heat intolerance
- A distorted body image
- Dysphagia (difficulty swallowing)
- Oligo- or amenorrhoea (i.e. few / no periods)
- Polyuria & polydipsia
Heat intolerance
Oligo or amenorrhoea
Other: thyrotoxicosis causes weight loss with hyperphagia (increased appetite). Goitres rarely cause dysphagias. Type 1 diabetes should be excluded in a young person with weight loss.
Define Graves’ disease.
Graves’ disease is an autoimmune thyroid condition associated with hyperthyroidism. TSH receptor antibodies cause the hyperthyroid syndrome.
How common is Graves’ disease?
In iodine sufficient parts of the world: 0.2-1.3%
Graves is the most common cause of hyperthyroidism
Usually seen in women aged 30-50yrs
In areas of iodine deficiency and endemic goitre: toxic multinodular goitre
What is the pathophysiology of Graves’ disease?
Autoimmunity - anti-TSH receptor antibodies stimulate the thyroid and cause hormone overproduction and hypertrophy of thyroid follicular cells
Other thyroid antibodies can also occur antithyroglobulin (Tg), antithyroid peroxidase (TPO) and antibodies to NaI transporter
What are the clinical features of Graves’?
Eye signs - exophthalmos, ophthalmoplegia
Pretibial myxoedema
Thyroid acropathy - triad of: digital clubbing, soft tissue swelling of hands and feet, periosteal new bone formation.
Signs and symptoms:
- heat intolerance
- sweating
- weight loss
- palpitations - AF/SVTs
- irritability
- scalp hair loss
- generalised proximal muscle weakness
- menstrual irregularities, gynaecomastia, ED
- tremor
- tachycardia, wide pulse pressure
- diffuse goitre
- orbitopathy - bilateral proptosis, lid retraction, inflammation, diplopia.
- cardiac flow murmur - from increased flow of blood through heart valves
What are the risk factors for Graves’ disease?
- FH of AI thryoid disease
- female sex - x4-9 more common
- tobacco use
- high iodine intake
- biological/cytokine therapies
- radiation
- radioiodine therapy for benign nodular goitre
- stress
What investigations would you do for Graves’ disease?
- TSH - suppressed <0.01 mIU/L
- T4 - elevated (good for monitoring therapy)
- Total T3/T4 or FT3/FT4 ratio - high compared to thyroiditis. May be helpful to distinguish Graves’ from toxic nodular goitre.
- Radioactive iodine or technetium-99 uptake scan - diffuse uptake
- Anti-TSHr, anti-TPO - positive
- Thyroid US - large, highly vascular, diffuse
- CT/MRI scan of orbit - shows muscle thickening
How do you manage Graves’?
Aim to normalise thyroid function by antithyroid meds, radioactive iodine ablation or surgery, depending on patient.
- Symptomatic therapy - propranolol - normalises peripheral thyroid hormone levels [alternatively: CCB]
- Antithyroid drugs (1st line) - PTU/carbimazole/ thiamazole - given for 12-18 months with aim of achieving remission. Start with higher doses then titrate to lower maintenance.
- Radioactive iodine - reserved for patients who prefer these approaches. Although NICE recommends this first line, but this is CI in thyroid orbitopathy.
- Surgery - for those planning pregnancy or with large goitres
- Orbitopathy - stop smoking, lubricant eye drops, IV methylprednisolone, immune modulation (MMF) and immunosuppression
- Dermopathy - topical corticosteroids
Which of these (1) is seen in all thyrotoxicosis cases, not just Graves?
- Proptosis
- Periorbital oedema
- Lid retraction and lid lag
- Diplopia due to extraocular muscle dysfunction
- Grittiness with increased tear production
Lid retraction and lid lag
All others are seen in Graves’ only
What is shown on each radioisotope scan?
What is shown?
Pretibial myxoedema - non pitting oedema
What eye signs are shown?
Lid retraction
Mild proptosis
Mild chemosis
