Thyroid Disorders Flashcards
Causes of hypothyroidism and associated general features:
- Hashimoto’s: most common developed world, autoimmune, transient thyrotoxicosis acute phase, 5-10 times more common in women
- Subacute (De Quervain’s) thyroiditis: painful goitre and raised ESR
- Riedel thyroiditis: fibrous tissue displacement, painless goitre
- Postpartum
- Drugs: lithium, amiodarone
- Iodine deficiency: most common developing world
Causes of hyperthyroidism:
- Grave’s disease
- Toxic multinodular goitre
- Drugs: amiodarone
Typical symptoms of hypothyroidism:
- cold intolerance
- weight gain
- lethargy
- dry, anhydrous, yellowish skin
- non-pitting oedema
- dry scalp
- loss of lateral aspect of eyebrow
- constipation
- menorrhagia
- decreased deep tendon reflexes
- carpal tunnel syndrome
Typical symptoms of hyperthyroidism:
- heat intolerance
- weight loss
- restlessness
- palpitations
- increased sweating
- pretibial myxoedema
- thyroid acropachy: clubbing
- diarrhoea
- oligomenorrhea
- anxiety and tremor
TSH and Free T4 in Thyrotoxicosis
- low TSH
- High T4
TSH and Free T4 in Primary Hypothyroidism
- high TSH
- low T4
TSH and Free T4 in Secondary Hypothyroidism
- low TSH
- low T4
TSH and Free T4 in sick euthyroid syndrome
- low/normal TSH
- low T4
TSH and Free T4 in subclinical hypothyroidism
- high TSH
- normal T4
TSH and Free T4 in poor compliance with thyroxine
- high TSH
- normal T4
Risk factor for Grave’s
smoking
Specific features of Grave’s disease
- eye signs (30%): exophthalmos, diplopia, ophthalmoplegia
- pretibial myxoedema
- thyroid acropachy
- autoantibodies: TSH receptor stimulating Ab (90%), anti-thyroid peroxidase Ab (75%)
Management of Grave’s disease
- propranolol to block adrenergic effects
- ATD titration (start carbimazole 40mg), 12-20 months
- block and replace (thyroxine when euthyroid), 6-9 months
- radioiodine (contra in pregnancy and <16yo)
What is Hashimoto’s associated with?
autoimmune disease, T1DM, Addison’s , pernicious anaemia
Secondary hypothyroidism causes:
- pituitary failure
- Down’s
- Turner’s
- Coeliac’s
Management of hypothyroidism:
- 50-100mcg levothyroxine od
- reduce to 25mcg od in elderly >50yo and ischaemic HD
- if changing dose, TFTs in 8-12 weeks
- increase dose by 25-50mcg in pregnancy
ADR of levothyroxine
- hyperthyroidism
- reduced bone mineral density
- worsening angina
- AF
Signs of congenital hypothyroidism:
- prolonged neonatal jaundice
- delayed mental and physical milestones
- short stature
- puffy face, macroglossia
- hypotonia
Screening for congenital hypothyroidism
at 5-7 days with heel prick test
Specific features in Hashimoto’s
- goitre firm non-tender
- anti-thyroid peroxidase and anti-thyroglobulin Ab
- assocaited with development of MALT lymphoma, coeliac, T1DM, vitiligo
Hormone profile, clinical features causes and treatment of primary hyperparathyroidism:
Hormones: -increased PTH -increased calcium -reduced phosphate -urine calcium: creatinine CR >0.01 -diagnose with technetium - MIBI subtraction scan Features: -may be asymptomatic -bones, stones, abdominal groans and psychic moans -polydipsia, polyuria -recurrent abdominal pain (peptic ulcers, constipation, pancreatitis) -changes to emotional state -pepperpot skull Causes: -solitary adenoma -hyperplasia -multiple adenoma -parathyroid carcinoma Treatment: -total parathyroidectomy -conservative if calcium <0.25mmol/L above upper limit and >50yo and no end organ damage -calcimimetic agents e.g. cinacalcet
Indications for surgery in primary hyperparathyroidism:
- increased serum calcium
- hypercalciuria
- reduced creatinine clearance
- episode of life threatening hypercalcaemia
- nephrolithiasis
- <50yo
- neuromuscular syndrome
- reduced bone mineral density
Hormone profile, clinical features and causes of secondary hyperparathyroidism:
Hormones: -increased PTH -increased phosphate -reduced calcium -reduced vit D Features: -bone disease -osteitis fibrosa -soft tissue calcifications Causes: -parathyroid gland hyperplasia -almost always in setting of chronic renal failure
Indications for surgery in secondary hyperparathyroidism:
- bone pain
- persistent pruritus
- soft tissue calcifications