Hypothyroidism Flashcards
Epidemiology of hypothyroidism
F>M=6:1
Age: >40yrs
Symptoms of hypothyroidism
Appetite loss with weight gain Insensitivity to cold Constipation Fatigue and lethargy Low mood Menorrhagia
Signs of hypothyroidism
Cold hands Bradycardic Slow-relaxing reflexes Dry hair and skin Puffy face Goitre Ascites Periorbital oedema
Myedema coma
When hypothyroidism left untreated
Features:
- Looks hypothyroid
- Hypothermia
- Hypoglycaemia
- Heart failure: bradycardia and ↓BP
- Coma and seizures
Causes of hypothyroidism
Atrophic thyroiditis Hashimoto’s thyroiditis Iodine deficiency - simple goitre Drugs: carbimazole, amiodarone, lithium Congenital: thyroid agenesis
Post surgical: after radio-iodine or thyroidectomy
Atrophic Thyroiditis
Thyroid antibodies +ve: anti-TPO, anti-TSH
Lymphocytic infiltrate → atrophy
Associations:
- Pernicious anaemia
- Vitiligo
Hashimoto’s disease
TPO ab +ve
Atrophy + regeneration → goitre
May go through initial thyrotoxicosis phase
Thyroperoxidase role
Catalyses oxidations steps of:
- iodine activation
- iodination of tyrosine residues
- coupling
Ix
Thyroid and cardiac exam
Basic obs
Bloods - TFTs, FBC
Antibodies - TPO, TSH
TFTs
High TSH
Low T3/T4
Which thyroid hormone is the active form
T3
Tx of hypothyroidism
Levothyroxine
- Clinical improvement takes ~2wks
Precipitants of myxoedema coma
Radioiodine
Thyroidectomy
Pituitary surgery
Infection, trauma, MI, stroke
Mx of myxoedema coma
Bloods: TFTs, FBC, U+E, glucose, cortisol Correct any hypoglycaemia T3/T4 IV slowly Hydrocortisone 100mg IV Tx hypothermia and heart failure
de Quervain’s thyroiditis - subacute thyroiditis
Associated with decreased iodine uptake
Diffuse painful goitre
Preceding viral URTI common - Coxsackie virus
Thyrotoxicosis → hypo→ eu
Tx - self limiting
