Thyroid disease Flashcards
Describe the different classifications and causes of hyperthyroidism and what would be seen on a thyroid function test?
Primary: Pathology within the thyroid.
- Toxic multinodular goitre
- Toxic adenoma (solitary nodule)
- High T3/4 low TSH
Secondary: Over activity secondary to increased circulating TSH or thyroid stimulating immunoglobulins.
Graves disease: (most common cause)
- Autoimmune condition
- TSI’s stimulated thyroid gland.
- Small to moderate firm goitre.
- Exopthalamus (50%)
- High T3/4 Low TSH.
- Presence of auto antibodies.
Pituitary adenoma (v rare)
- High TSH
- High T3/T4
- Low TRH
Iatrogenic:
Amiodarone, Lithium, exogenous iodine (too much thyroxine)
Describe the classical symptoms of a patient with hyperthyroidism?
Mood:
- Irritability.
- Agitation and difficulty sleeping.
- Anxiety.
Energy:
- Proximal weakness.
- Resting fine tremor.
- Heat intolerance
Metabolism:
- Increased hunger
- Weight loss
Cardiac:
- AF
Reproductive:
- Ammenorrhoea/Oligmenorrhoea
- Lack of libido
Bowels:
- Diarrhoea
Discuss how thyroid disease is investigated?
- Thyroid function tests.
- Neck swelling = US scan
- Antibody testing for Graves and Hashimotos
Graves: TSI
Hashimotos: Anti TPO
What are the specific antibodies found in Grave’s disease?
Thyroid stimulating immunoglobulin (TSI) also known as:
Thyroid stimulating hormone receptor antibody (TRAb)
Describe the medical management of hyperthyroidism?
Symptomatic relief for palpitations can be given with beta blockers.
Carbimazole: Blocks the actions of TPO
- Titrate dose according to T3/T4 levels
- Treat for 12-18 months
- Can cause agranulocytosis
Describe the non pharmacological management of hyperthyroidism?
Options if there has been failed medical management.
Radioactive Iodine:
- Increased uptake by the ‘hot spots’
- Often causes iatrogenic hypothyroidism.
Surgery: Thyroidectomy
Can often cause:
- Hypoparathyroidism
- Hypothyroidism
- May cause recurrent laryngeal nn damage (hoarse voice)
Which thyroid disease are MALT lymphomas associated with?
Hashimoto’s thyroiditis.
List the common causes of hypothyroidism?
Primary hypothyroidism: 4 I’s Immune, Iatrogenic, Iodine deficiency, Infiltration. Low T3/T4 and low TSH.
Autoimmune hypothyroidism
Hashimoto’s thyroiditis
- Associated with a goitre
- Anti-thyroid peroxidase (anti-TPO) antibodies or anti-thyroglobulin antibodies.
Atrophic thyroiditis
- No goitre
- Most common cause in the UK
Iatrogenic
- Drugs: Carbimazole, amiodarone, lithium.
- Radioactive iodine
- Radiotherapy or surgery.
Iodine deficiency
- Most common cause worldwide
- Large nodular goitre
Infiltration of the thyroid:
- Amyloidosis, sarcoidosis and haemochromatosis.
Secondary hypothyroidism:
Hypopituitarism:
- Neoplasm, infiltrative, infection and radiotherapy.
Hypothalamic disorders
- Neoplasms and trauma.
- Low T3/T4, low TSH and low TRH.
Describe the classical symptoms of hypothyroidism?
Mood:
- Difficulty concentrating.
Appearance:
- Dry skin
- Hair loss
- Myxoedema (face hands and feet)
Energy:
- Tiredness + Lethargy
- Cold intolerance + cold peripheries
Metabolism:
- Weight gain despite decreased hunger
Bowels:
- Constipation
Reproductive:
- Reduced libido
- Mennorhagia ———> Oligmoennorhagia/ammenorhagia
Cardiac:
- Bradycardia
Complications:
- Carpal Tunnel syndrome
- Serious cavity effusions
How is hypothyroidism treated?
Usually treated with replacement T4 aka thyroxine (levothyroxine)
Titrate dose to normalise TSH
Note enzyme inducers will increase the metabolism.
What is the morphology of a nodular goitre?
It is different to the goitres seen in Grave’s and Hashimoto’s disease which are smooth and diffuse (aka swellings of the thyroid.
Multinodular goitres can sometimes be associated with hyperthyroidism.
Nodular goitres are lumpy.
May be a single nodule or multinodular.
What is a major complication of hypothyroidism?
Myxoedema Coma
- Looks hypothyroid
- Hypothermia
- Hypoglycaemia
- Heart failure: bradycardia and low BP
- Coma and seizures
Describe the precipitating factors of a myxoedema coma?
Precipitants:
- Radioiodine
- Thyroidectomy
- Pituitary surgery
- Infection, trauma
Describe the management of a myxoedema coma?
- Bloods: TFTs, FBC, U+E, glucose, cortisol
- Correct any hypoglycaemia
- T3/T4 IV slowly (may ppt. myocardial ischaemia) Hydrocortisone 100mg IV
- Treat hypothermia and heart failure
What are the potential causes of nodular goitres and what are the pathological consequences?
Multinodular Goitres: Often unknown cause.
Can be toxic aka causing symptoms of hyperthyroidism.
Nodular Goitres:
- Cyst
- Adenoma
- Malignancy
