Thyroid Disease Flashcards
What is alemtuzumab?
An anti-CD52 monoclonal antibody
What is the effect of of alemtuzumab?
Depletes autoreactive lymphocytes rapidly causing immune suppression followed by B cell recovery leading to B cell mediated autoimmunity
What are the most common side effects of alemtuzumab?
Autoimmune disease – graves disease, ITP, haemolytic anaemia, anti GBM GN
How does biotin cause spurious TFTs?
Excess of biotin occupies the binding sites in the assay causing falsely elevated levels of T3 and T4 and falsely low TSH
What types of thyroid dysfunction are caused by amiodarone?
Hypothyroidism (most common)
Amiodarone-induced thyrotoxicosis type 1 (increased denovo thyroid hormone synthesis)
Amiodarone-induced thyrotoxicosis type 2 (destructive thyroiditis)
How does amiodarone cause thyroid dysfunction?
Inhibits conversion of T4 to T3
Toxic to thyroid follicular cells
Iodine effect (high iodine content)
What is the treatment for amiodarone induced thyrotoxicosis?
Prednisolone and carbimazole
What is the difference in timing between AIT type 1 and AIT type 2?
AIT type 1 more common in early phase
AIT type 2 more common in late phase
Which is more common AIT type 1 or 2?
AIT type 2
Are thyroid autoantibodies positive in AIT?
May be positive in type 1
Which responds more quickly to prednisolone AIT type 1 or 2?
Type 2
What are the endocrine side effects of CTLA4 inhibitors (ipilimumab)?
Hypophysitis and hypothyroidism
What are the endocrine side effects of PD-1 inhibitors (pembrolizumab, nivolumab)?
Hypo or hyperthyroidism
What are the endocrine side effects of lithium?
Hypothyroidism, parathyroid hyperplasia, nephrogenic diabetes insipidus
What is the mechanism of action for lithium causing hypothyroidism?
Inhibits pinocytosis
What are predisposing factors to lithium hypothyroidism?
Female
Age > 40
Presence of TPO antibodies
Duration of use
Which drugs increase thyroid binding proteins?
Oestrogen, SERM, methadone, heroin, mitotane, 5FU
Which drugs decrease thyroid binding proteins?
Androgen, glucocorticoids, niacin
What are the causes of primary hyperthyroidism?
Graves’ disease Toxic MNG Toxic adenoma Early thyroiditis Drugs Excess iodine Excess thyroxine Hyperemesis gravidarum Hydatidiform mole
What are the pathognomonic signs of Graves disease?
Diffuse goitre
Thyroid eye disease
Peritibial myxoedema
Acropachy (clubbing)
What are the signs of thyroid eye disease?
Bilateral proptosis
Periorbital oedema
Scleral injection
Lid retraction
In which graves disease patients is radioactive iodine contraindicated?
Patients with severe thyroid eye disease – will exacerbate
What is the differential diagnosis for primary hypothyroidism?
Hashimoto’s thyroiditis Post radioiodine therapy Post thyroidectomy Subacute thyroiditis Drugs Neck irridation Riedel’s thyroiditis (rare) Thyroid infiltration e.g. amyloid (rare) Congenital hypothyroidism
What diseases is subclinical hyperthyroidism associated with?
Cardiovascular disease (AF, CCF, CAD), bone loss, fractures, dementia
