Presentation and management of hypo/hyperthyroidism Flashcards
What are the most common endocrine disorders?
Thyroid diseases
How many times greater are there females with thyroid disease than males?
5-10 fold
What are the prevalence of hyperthyroidism, hypothyroidism and goitre?
- Hyperthyroidism 2.5% prevalence
- Hypothyroidism 5%
- Goitre 5-15%
What are examples of thyroid autoimmunity?
- Focal thyroiditis and/or positive TPO and thyroglobulin antibodies
- Postpartum thyroiditis
- Autoimmune hypothyroidism
- Graves’ disease
What are examples of autoimmune hypothyroidism?
- Hashimoto’s thyroiditis
- Atrophic thyroiditis
What happens in Graves’ disease?
Thyroid associated ophthalmopathy
What is found in almost all patients with autoimmune hypothyroidism?
Thyroglobulin and thyroid peroxidase (TPO) antibodies
Where are thyroglobulin and thyroid peroxidase (TPO) antibodies also found?
- Also present in 75% Graves’ patients
- Low levels present in healthy individuals at risk of thyroid or other autoimmune disease
What mediates the destruction of thyroid cells?
Cytotoxic (CD8+) T cell-mediated
What is goitre?
- Palpable & visible thyroid enlargement
- Variety of causes
- Commonly sporadic or autoimmune
- Endemic in iodine deficient areas
- Thyroid tries to compensate and goes through hyperplastic change
Define hyperthyroidism
excess of thyroid hormones in blood
What are the 3 mechanisms for increased thyroid hormone?
- overproduction thyroid hormone
- leakage of preformed hormone from thyroid
- ingestion of excess thyroid hormone
What are causes of hyperthyroidism?
- Common
- Graves’ disease (75- 80% of all
cases) - Toxic multinodular goitre
- Toxic adenoma
- Congenital hyperthyroidism
- Thyroiditis
(subacute/silent/postpartum)
- Graves’ disease (75- 80% of all
Which drugs could cause hyperthyroidism?
- Iodine
- Amiodarone
- Lithium?
- Radiocontrast agents
What are clinical features of hyperthyroidism?
- Wt loss
- Tachycardia
- Hyperphagia
- Anxiety
- Tremor
- Heat intolerance
- Sweating
- Diarrhoea
- Lid lag + stare
- Menstrual disturbance
- Heavy periods
What are the specific signs of Graves’?
- Diffuse goitre
- Thyroid eye disease (infiltrative)
- Pretibial myxoedema
- Acropachy
What is a sign of MNG?
Multinodular goitre
What is a sign of adenoma?
Solitary nodule
What are the investigations for hyperthyroidism?
- Thyroid function tests to confirm biochemical hyperthyroidism
- Diagnosis of underlying cause important because treatment varies
- Clinical history, physical signs usually sufficient for diagnosis
- Supporting investigations
What is most commonly on thyroid function tests for hyperthyroidism?
TSH supressed, T3, T4 elevated in primary hyperthyroidism
(In secondary hyperthyroidism high free T4, high free T3 but inappropriately high TSH)
What is the treatment for hyperthyroidism?
- Antithyroid drugs (course or long-term)
- Radioiodine (131)I
- Surgery (partial, subtotal thyroidectomy)
Define hypothyroidism
Thyroid hormones levels abnormally low
What are the 3 types of hypothyroidism?
- Primary (>99%)
- absence / dysfunction thyroid gland
- most cases due to Hashimoto’s thyroiditis - Secondary/ tertiary
pituitary / hypothalamic dysfunction
What are causes of adult PRIMARY hypothyroidism?
● Hashimoto’s thyroiditis
● Thyroidectomy
● Iodine deficiency
What are causes of adult SECONDARY/TERTIARY hypothyroidism?
- Pituitary disease
- Hypothalamic disease
What are drugs that cause hypothyroidism?
- Iodine
- Lithium
- Thionamides
What are causes of child hypothyroidism?
● Neonatal hypothyroidism
● Resistance to thyroid hormone
● Isolated TSH deficiency
What are clinical features of hypothyroidism?
● Weight gain
● Fatigue
● Dry, rough skin
● Menstrual disturbance
● Constipation
● Cold intolerance
What would thyroid investigations of primary hypothyroidism show?
● Increased TSH usually decreased free T4, decreased T3
● T4/ T3 may be below normal in positive titre of TPO antibodies in Hashimoto’s
What would thyroid investigations of secondary/tertiary hypothyroidism show?
TSH inappropriately low for reduced T4 / T3 levels
What is the treatment for hypothyroidism in young adults?
- usual full replacement of 100µg - titrate according to TSH
- Requirements vary according to cause eg. higher doses in thyroid ablation
How would you monitor treatment in hypothyroidism?
- Dose titrated until TSH normalises
- T4 half-life is long – check levels 6-8 weeks after dose adjustment
- In secondary/ tertiary hypothyroidism TSH will always be low, T4 is monitored
