Thyroid Disease

Hyperthyroidism

Thyrotoxicosis is a syndrome caused by excess thyroid hormones in the body. However, it’s usually caused by a sudden release of these stored hormones rather than gland overactivity.

Presentation:

• Weight loss

• Diarrhoea

• Tachycardia/AF

• Palpitations

• Oligo/Amenorrhoea

• Heat intolerance

• Hair loss

• Irritability

• Muscle weakness

• Insomnia

Features suggestive of Grave’s disease - Exophthalmos, Ophthalmoplegia, Periorbital oedema, Pretibial Myxoedema (waxy skin)

Causes:

• Grave’s disease - Most common - Autoimmune production of TSH receptor antibodies, which mimic TSH and stimulate its receptors, leading to primary hyperthyroidism

• Toxic multinodular goitre

• Solitary toxic adenoma

• Acute thyroiditis (e.g. De Quervain’s) - painful goitre

• Drugs - Amiodarone, Lithium

• Choriocarcinoma

Complications - Thyroid storm, AF, HF, Osteoporosis, Upper airway obstruction if large goitre, Corneal ulcers/visual loss

Management:

• B-blocker (e.g. propranolol) for symptomatic relief

• Carbimazole or Propylthiouracil - titration-block or block and replace regimens

  • SE to remember for Carbimazole is Agranulocytosis

N.B. Propylthiouracil better option in early pregnancy.

Radioactive iodine is another medical option, but should be avoided in those with Grave’s eye disease as it many worsen it.

Thyroidectomy is an option if compression or malignancy is suspected. Complications of this are:

• Hypoparathyroidism (hypocalcaemia)

• Recurrent laryngeal nerve damage (hoarse voice)

• Hypothyroidism - will require Levothyroxine

Hypothyroidism

Presentation:

• Weight gain

• Constipation

• Bradycardia

• Menorrhagia

• Cold intolerance

• Loss of lateral 1/3 of eyebrow

• Memory loss

• Puffy face

• Fluid retention (edema, pleural effusions, ascites)

Causes:

• Iodine Deficiency - Most common

• Hashimoto’s Thyroiditis - Autoimmune inflammation of thyroid, associated with anti-TPO, anti-thyroglobulin, and anti-TSH receptor.

• Drugs - Amiodarone, Lithium

• Post-hyperthyroid treatment - Carbimazole, Radioactive iodine, Thyroidectomy

• Hypopituitarism (less TSH) - due to tumour, infection, radiation, sheehan syndrome

Investigations:

• Primary - Low TH, High TSH

• Secondary - Low TH, Low TSH

Management - Levothyroxine

Sick Euthyroid

This is where there are low TH levels in patients who are ill/starved, but are normally euthyroid.

This occurs in periods of illness or starvation, as the body enters a catabolic state in which breaks down it’s own proteins for energy. When the stores for energy run out, the body then stops producing as many proteins. One of these proteins are the THs, therefore leading to a deficiency.

It’s managed by treating the underlying cause.