Thyrotoxicosis Flashcards
What is thyrotoxicosis.
The clinical effect of excess thyroid hormone, usually from gland hyperfunction.
What are the symptoms of thyrotoxicosis. (16)
Diarrhoea. Weight loss (if very high, paradoxical weight gain in 10%). Over active. Sweats. Heat intolerance. Palpitations. Tremor. Irritability. Labile emotions. Oligomenorrhoea and infertility.
Rarely: Psychosis. Chorea. Panic. Itch. Alopecia. Urticaria.
What are the clinical signs of thyrotoxicosis. (8)
Fast pulse (AF, SVT, VT rare). Warm moist skin. Fine tremor. Palmar erythema. Thin hair. Lid lag. Lid retraction. There may be goitre, thyroid nodules or bruits depending on the cause.
What are the specific signs of graves’ disease. (4)
Exophthalmos.
Ophthalmoplegia.
Pretibial myxoedema.
Thyroid acropachy (extreme manifestation, with clubbing, painful finger and toe swelling and periosteal reaction in limb bones).
What do you see on the TFTs in a patient with thyrotoxicosis. (2)
Low TSH (suppressed). High T3 and T4.
What may be seen on the blood results of a patient with thyrotoxicosis. (5)
There may be a mild normocytic anaemia. Mild neutropenia (in Graves). Raised ESR. Raised calcium. Raised LFTs.
What other tests should you do in a patient with thyrotoxicosis. (4)
Check thyroid autoantibodies.
Isotope scan if the cause is unclear (to detect nodular disease or subacute thyroiditis).
If ophthalmopathy test visual fields and eye movements.
What are the causes of thyrotoxicosis. (6)
Graves' disease. Toxic multinodulat goitre. Toxic adenoma. Ectopic thyroid tissue. Exogenous. Other (Subacute de Quervain's thyroiditis, drugs, postpartum, TB).
What is the prevalence of graves.
0.5%.
What proportion of hyperthyroid cases are due to graves.
2/3rds.
What is the female:male ratio for graves.
9:1.
What is the typical age of onset of graves. (2)
40-60.
Younger if there is a maternal family history.
What is the cause of grave’s disease.
Circulating IgG autoantibodies binding to and activating G protein coupled thyrotropin receptors.
What is the aetiology of graves. (3)
Smooth thyroid enlargement.
Increased hormone production (raised T3).
React with orbital autoantigens.
What are some triggers for grave’s disease. (3)
Stress.
Infection.
Childbirth.
What are some associations of graves. (3)
Vitiligo.
T1DM.
Addison’s.
Who is toxic multinodular goitre often seen in. (2)
Elderly.
In iodine deficient areas.
What is toxic multinodular goitre.
Nodules that secrete thyroid hormones.
What is the treatment for toxic multinodular goitre.
Surgery is indicated for compressive symptoms from the enlarged thyroid (dysphagia or dyspnoea).
What is a toxic adenoma.
A solitary nodule producing T3 and T4.
What does a toxic adenoma look like on an isotope scan. (2)
Hot.
The rest of the gland is suppressed.
What is extopic thyroid tissue.
Metastatic follicular thyroid cancer, or struma ovarii.
It is an ovarian teratoma with thyroid tissue.
What are the exogenous causes of thyrotoxicosis. (3)
iodine excess in food.
From contrast media (thyroid storm).
Levothyroxine excess causes raised T4, low T3 and low thyroglobulin.
What is subacute de Quervain’s thyroiditis.
Self-limiting post-viral with painful goitre.
What is seen in subacute de Quervain’s thyroiditis. (3)
Painful goitre.
Fever.
Raised ESR.
What is seen on the iodine uptake scan in de Quervain’s thyroiditis.
Low uptake.
What is the treatment for de Quervain’s thyroiditis.
NSAIDs.
What drugs cause thyrotoxicosis. (2)
Lithium.
Amiodarone.
What are the complications of thyrotoxicosis. (7)
Heart failure (throtoxic, cardiomyopathy, in elderly). Angina. AF (seen in 10-25%). Osteoporosis. Ophthalmopathy. Gynaecomastia. Thyroid storm.
What are some causes of a diffuse goitre. (4)
Physiological.
Graves’ disease.
Hashimoto’s thyroiditis.
Subacure (de Quervain’s) thyroiditis (painful).
What are some nodular causes of a goitre. (3)
Multinodular goitre.
Adenoma.
Carcinoma.
What is the female:male ratio for a thyroid storm.
4:1.
What are the symptoms of a thyroid storm. (11)
Fever. Agitation. Confusion. Coma. Tachycardia. AF. Diarrhoea and vomiting. Goitre. Thyroid bruit. Acute abdomen (exclude a surgical cause). Heart failure. Cardiovascular collapse.
What are the precipitants of a thyroid storm. (4)
Recent thyroid surgery. Recent radioiodine. Infection. MI. Trauma.
What tests should you do in a patient with thyroid storm. (3)
TSH.
Free T4 and T3.
Confirm with technetium uptake if possible.
Do not wait for a positive diagnosis to treat.
What are the principles of treatment of thyroid storm. (3)
Counteract peripheral effects of thyroid hormones.
Inhibit thyroid hormone synthesis.
Treat systemic complications.
How do you treat a thyroid storm. (6)
IV fluids.
If no contraindications and good CO give propanolol.
High dose digoxin may be needed.
Antithyroid drugs (carbimazole).
Hydrocortisone IV.
Treat suspected infections with co-amoxiclav.
How do you treat thyrotoxicosis. (3)
Drugs (beta blockers such as propanolol for rapid control of symptoms; antithyroid meds: titrate carbimazole or total block replace).
Radioiodine (most become hypothyroid post treatment).
Thyroidectomy (carries risk of damage to recurrent laryngeal nerve).
What is the risk associated with carbimazole treatment.
Agranulocytosis.
What are the features of agranulocytosis.
Very low neutrophils, can lead to a dangerous sepsis.
What is the incidence of agranulocytosis caused by ccarbimazole.
0.03%.
What are the symptoms that patients need to look out for if they are being treated with carbimazole.
If they have signs of infection (fever, sore throat, mouth ulcers, etc…).
