Endocrine

Thyrotoxicosis

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Pathology

Increased T3 and/or T4 (usually both) due to excess production causing increased basal metabolic rate and multiple end-organ effects

Aetiology

Primary: Autonomous thyroid in multinodular goitre or autoimmune 
hyperthyroidism (Graves’ Disease) 
Secondary: Thyrotroph pituitary tumour, thyroiditis from drugs (e.g. 
amiodarone), infections, post-partum, radiation, inappropriate use   
of thyroxine medications

Signs

Fine tremor, tachycardia, warm moist skin, palmar erythema, hair loss, muscle wasting/ weakness, brisk reflexes, signs of congestive cardiac failure
Graves’ Disease: May have neck swelling and eye signs, proximal myopathy, 
pre-tibial myxoedema, thyroid acropachy
Eye Signs: Exophthalmos, proptosis, ophthalmoplegia

Symptoms

Anxiety, hyperactivity, sweating, heat intolerance, palpitations, weakness, weight loss, increased stool frequency, pruritus, oligo/amenorrhoea 

Investigations

Bloods: Thyroid function tests (TFTs): Increased T4,  Increased T3, Decreased 
TSH , Antithyroid peroxidase (TPO) antibodies, TSH receptor (TRAb) 
antibodies (Graves’ Disease) 
Imaging: ultrasound thyroid, thyroid uptake scan

Treatment

Medical: Symptomatic treatment with beta blockers (Propranolol) and 
anti-thyroid drugs (Carbimazole, Propylthiouracil) 
Radiation: Radioiodine therapy
Surgery: Thyroidectomy

Prognosis

Usually good. Can cause exacerbation of pre-existing heart failure or arrhythmias
Atrial fibrillation, heart failure, osteoporosis

Key Facts

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Key References

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