Endo - Hyperthyroidism Flashcards
What 2 ways does TSH cause and increase in thyroid hormone
Stimulates thyroxine production
Stimulates proteolytic enzymes to eat away colloid and release bound thyroxin into circulation
What regulates thyroid production
Negative feedback of T3 and T4 on the pituitary and the hypothalamus
What happens in primary hypothyroidism?
Immune system makes anti-thyroid antibodies therefore reduces the thyroid gland output
What happens in Grave’s disease?
Autoimmune condition whereby antibodies bind to TSH receptors and cause hyperthyroidism
What are the symptoms of Grave’s disease
Sweating Flushing Palpable lymph nodes Muscle wasting Shortness of breath Breast enlargement/ gynaecomastia Weight loss Heat intolerance Tachycardia Pretibial myxoedema Smooth diffuse goitre Tremor Irritability Increased appetite Exophthalmos Insomnia Diarrhoea
What causes exophthalmos
Separate autoantibodies bind to the muscles behind the eye
What causes an increase in heart rate and palpitations?
Increased thyroid hormone to increase sensitivity to adrenaline
What causes an increase in body temperature?
Increase in BMR
What causes pretibial myxoedema
Third antibody binds to the front of the tibia
How do we treat pretibial myxoedema
Topical steroids/ local injection to reduce inflammation
What does myxoedema usually refer to
Primary hypothyroidism
What is pretibial myxoedema?
Non pitting swelling that occurs in the tibial soft tissue of Grave’s disease patients
Describe the goitre seen in Grave’s
Smooth diffuse goitre that is uniform on both sides
How do we visualise the goitre in Grave’s
Radioactive iodine
What is Plummer’s disease?
Toxic nodular goitres which secrete T4
Is Plummer’s autoimmune?
No
As a result of Plummer’s not being autoimmune, what do we not see compared to Grave’s?
We don’t see exophthalmos or pretibial myxoedema
Why does Plummer’s give us an uneven appearance of thyroid gland?
Because the normal thyroid gland shrinks as only the nodular hot thyroid secretes hormones
What can we do to treat Plummer’s?
Hot nodule can be physically removed or we can give radioiodine
What are the effects of thyroxine?
Sensitises beta adrenoreceptors to ambient levels of adrenaline and noradrenaline
Apparent sympathetic activation
Tachycardia
Palpitations
Tremors in hands
Lid lag
What is thyroid storm?
Medical emergency arising form untreated hyperthyroidism
Why is thyroid storm an emergency?
50% mortality if left untreated - but is completely treatable
What are the signs of thyroid storm?
Hyperpyrexia (>41) Tachycardia (170+)/ arrhythmia Cardiac failure Delirium/psychosis Hepatocellular dysfunction; jaundice
How do we treat thyroid storm?
Thyroidectomy - can change voice
Radioiodine -radioactive for 6 days
Drugs
