Thyroid Disorders and Thyroid in Pregnancy Flashcards
What happens in the thyroid axis?
Hypothalamus -> TRH -> AP -> TSH -> thyroid -> T3 and T4.
T3/4 have negative feedback effect on the pituitary gland and hypothalamus
What would happen to TSH levels if you under-active thyroid?
TSH would be raised as you have less T3/4 being produced and so no negative feedback.
What does low TSH indicate?
Low TSH indicates an over-active thyroid
Lots of T4 and T3 is being produced and so there is more negative feedback on the pituitary and less TSH.
What are the main functions of T3/4?
- Food metabolism.
- Protein synthesis.
- Increased sympathetic action e.g. CO and HR.
- Heat production.
- Needed for growth and development.
What are 5 causes of hypothyroidism?
- Autoimmune thyroiditis e.g. Hashimoto’s and atrophic thyroiditis.
- Post-partum thyroiditis.
- Iatrogenic - thyroidectomy.
- Drug induced e.g. carbimazole, amiodarone, lithium.
- Iodine deficiency.
What are 3 antibodies that would be present in someone with autoimmune thyroiditis?
1) TPO (Thyroid peroxidase)
2) Thyroglobulin
3) TSH receptor
What are examples of each type of hypothyroidism?
1) Transient: Post-partum thyroiditis
2) Iatrogenic: Thyroidectomy, Radioiodine therapy
3) Drugs: Carbimazole, Lithium, Amiodarone
What are main symptoms of hypothyroidism?
1) Menorrhagia - heavy bleeding
2) Obesity/weight gain
3) Malar flush
4) Tiredness/fatigue
5) Declining energy levels, depression
6) eye brows loss, dry skin and hair
7) Intolerance to cold
8) GOITRE (Swelling of the thyroid gland)
What are the main things to test for in hypothyroidism?
1) Thyroid Antibodies
2) TFT –> T3/4 low, TSH will be higher
How is hypothyroidism managed?
Levothyroxine
What are two of the main causes of hyperthyroidism?
1) Grave’s Disease
2) Toxic Adenoma
What is thyrotoxicosis and what are some of the main causes?
Def: Excess thyroid levels from possible causes
1) Increased production e.g. Graves, Adenoma
2) T3/4 leakage from follicular damage
3) Ingestion
4) Thyroiditis
5) Drug induced
What is the pathophysiology of Grave’s disease?
AI disease
1) TSH receptor antibodies stimulate thyroid hormone production
2) Hyperthyroidism
Give 5 symptoms of Grave’s disease that don’t include ophthalmopathy signs.
(See Hyperthyroidism signs)
- Weight loss.
- Increased appetite.
- Irritable.
- Tremor.
- Palpitations.
- Goitre.
- Diarrhoea.
- Heat intolerance.
- Malaise.
- Vomiting.
What are 5 non-opthalmopathic signs of Grave’s disease
- Tachycardia.
- Arrhythmias e.g. AF.
- Warm peripheries.
- Muscle spasm.
- Pre-tibial myxoedema (raised purple lesions over the shins).
- Thyroid acropachy (clubbing and swollen fingers).
What are 5 opthalmopathic signs of Grave’s disease?
- Exophthalmos (bulging eyes).
- Lid lag stare.
- Redness.
- Conjuctivitis.
- Pre-orbital oedema.
- Bilateral.
- Extra-ocular muscle swelling.
What histological signs does Grave’s disease present?
Lymphocyte infiltration
Thyroid follicle destruction
What are 3 methods of treatment for Grave’s disease?
1) Surgery (Thyroidectomy)
2) Anti-thyroid drugs (Carbimazole)
3) Radioiodine drugs
How does carbimazole treat Grave’s disease and what is a potential side effect of taking it?
Targets thyroid peroxidase to prevent T3/T4 being produced
- Agranulocytosis
What are potential complications of a thyroidectomy?
- Bleeding.
- Hypocalcaemia.
- Hypothyroidism.
- Recurrent laryngeal nerve palsy.
How do radioiodine drugs work in treating Grave’s disease?
Thyroid hormone production is decreased, as radioiodine drugs emit beta particles destroying thyroid follicles
What are the 5 metabolical changes that occur in pregnancy?
- Increased EPO, cortisol and N. Adrenaline
- High CO.
- High cholesterol and triglycerides.
- Pro thrombotic and inflammatory state.
- Insulin resistance.
What are 6 syndromes found in gestational periods?
1) Gestational Diabetes
2) Pre-eclampsia
3) Obstetric cholestasis
4) Gestational thyrotoxicosis
5) Postnatal depression
6) Post-partum thyroiditis
At what week are T4 and foetal thyroid follicles synthesised?
Week 10
