[17] Thyrotoxicosis Flashcards
What is thyrotoxicosis?
The clinical effect of increased T4, usually from gland dysfunction
What are the symptoms of thyrotoxicosis?
Diarrhoea ↑ appetite but ↓ wt. Sweats, heat intolerance Palpitations Tremor Irritability Oligomenorrhoea ± infertility
What are the hand signs of thyrotoxicosis?
Fast/irregular pulse
Warm, moist skin
Fine tremor
Palmar erythema
What are the face signs of thyrotoxicosis?
Thin hair
Lid lag
Lid retraction
What are the neck signs of thyrotoxicosis?
Goitre or nodules
What are the graves specific signs of thyrotoxicosis?
Opthalmopathy
Dermaopathy
Thyroid acropachy
What are the opthamology signs of Graves?
Exopthalmos Opthalmoplegia, especially up-gaze palsy Eye discomfort and grittiness Photophobia and decreased acuity Chemosis
What are the dermopathy signs of Graves?
Pre-tibial myxoedema
What investigations should be done in thyrotoxicosis?
Bloods
Antibodies
Isotope scan
Eye testing
What may be found on bloods in thyrotoxicosis?
Decreased TSH, increased T3/4
Increased calcium
Increased LFTs
What antibodies should be checked for in thyrotoxicosis?
TSH receptor
TPO
What may be found on isotope scan in thyrotoxicosis?
Increased in Graves’
Decreased in thyroiditis
What should be done on eye testing in thyrotoxicosis?
Acuity
Fields
Movements
What % of cases of thyrotoxicosis is caused by Graves?
60%
What is the male:female ratio of Graves?
M:F = 1:9
What age is Graves disease most common?
40-60 years
What are the clinical features of Graves disease?
Diffuse goitre with increased iodine uptake
Opthalmopathy and dermopathy
What are the triggers for Graves disease?
Stress
Infection
Childbirth
What other conditions is Graves disease associated with?
T1DM
Vitiligo
Addison’s
What are the other causes of thyrotoxicosis?
Toxic multinodular goitre
Toxic adenoma
Thyrotoxic phase of thyroiditis
Drugs
What happens in a toxic multinodular goitre?
An autonomous nodule develops on a background of an multinodular goitre
Where are toxic multinodular goitres common?
Elderly
Iodine deficient areas
What does the iodine scan show in a toxic multinodular goitre?
Hot nodules
What is a toxic adenoma?
A toxic hot nodule producing T3 and T4
What conditions can cause a thyrotoxic phase of thyroiditis?
Hashimotos
De Quervain’s
Subacute lymphocytic thyroiditis
What drugs can cause thyrotoxicosis?
Thyroxine
Amiodarone
What is involved in the medical management of thyrotoxicosis?
Symptomatic management
Anti-thyroid drugs
What can be used in the symptomatic management of thyrotoxicosis?
Beta blockers, e.g. propanolol 40mg/6 hours
What anti-thyroid drug can be used in thyrotoxicosis?
Carbimazole
What is the mechanism of action of carbimazole?
Inhibits TPO
How should the dose of carbimazole be determined?
Titrate according to TFTs
Completely block, and replace with thyroxine
How long should carbimazole be given in Grave’s disease?
12-18 months
What % of patients relapse after 12-18 months of carbimazole treatment in Graves disease?
50%
What should be done if a patient relapses after 12-18 months in Graves disease?
Surgery or radioiodine
What are the side effects of carbimazole?
Agranulocytosis
What is involved in the radiological management of thyrotoxicosis?
Radio-iodine
What happens following radioiodine treatment for thyrotoxicosis?
Most become hypothyroid
What are the contraindications to radioiodine treatment in thyrotoxicosis?
Pregnancy
Lactation
What is involved in the surgical management of thyrotoxicosis?
Thyroidectomy
What are the potential adverse effects of thyroidectomy?
Recurrent larygneal nerve damage leading to voice hoarseness
Hypoparathyroidism
Hypothyroidism
What are the features of a thyroid storm?
↑temp Agitation, confusion, coma Tachycardia, AF Acute abdomen Heart failure
What are the precipitants of a thyroid storm?
Recent thyroid surgery or radio-iodine
Infection
MI
Trauma
How is a thyroid storm managed?
- Fluid resuscitation + NGT
- Bloods: TFTs + cultures if infection suspected
- Propranolol PO/IV
- Digoxin may be needed
- Carbimazole then Lugol’s Iodine 4h later to inhibit thyroid
- Hydrocortisone
- Rx cause