Endocrinology: Thyroid Disease Flashcards
Outline the pathophysiology of hyperthyroidism.
Graves = autoAbs activate thyrotropin receptors that increase hormone production
Toxic multinodular goitre = nodules that secrete hormone
Toxic adenoma = single nodule producing hormone
Ectopic tissue = metastatic follicular thyroid cancer
Outline the aetiology of hyperthyroidism.
Graves
Toxic multinodular goitre
Toxic adenoma
Ectopic thyroid disease
Iodine excess
What are the signs and symptoms of hyperthyroidism?
Diarrhoea
Weight loss
Increased appetite
Over-active
Sweats
Heat intolerance
Palpitations
Tremor
Oligomenorrhoea
Thin hair
Lid lag
Goitre
How would you investigate Hyperthyroidism?
Bloods = TSH secreting tumour – high TSH, high T4, hyperthyroidism – low TSH, high T4
Thyroid Abs = anti-thyroid peroxidase Abs, antithyroglobulin Abs
Isotope scan = iodine
How would you manage hyperthyroidism?
Beta blockers = control of symptoms
Carbimazole 20-40mg/24hr PO for 4 wks, reduce according to TFTs every 1-2 months
- SE: agranulocytosis (monitor WBC count)
Radioiodine = most pts become hypothyroid
Thyroidectomy = risk of damage to recurrent laryngeal N, hypoparathyroidism, hypothyroid
What are the complications of hyperthyroidism?
HF
Angina
AF
Osteoporosis
Opthalmopathy
Gynaecomastia
Outline the pathophysiology of hypothyroidism
Primary = prob with gland itself = autoimmune, not secreting (high TSH, low T3/4)
Secondary = pituitary problem = lesion (low TSH, low T3/4)
Congenital = dysgenesis (high TSH, low T3/4)
Outline the aetiology of hypothyroidism.
Congenital = maldescent (remains as lingual mass or unilobular gland), thyroid dysgenesis, dyshormonogenesis, iodine def, pit tumour, congenital sheehan syndrome, craniopharyngioma
Acquired = prematurity, hashimoto’s thyroiditis, hypopituitarism, trisomy 21, iatrogenic
What are the signs and symptoms of hypothyroidism?
- Tired, lethargic
- Low mood
- Cold intolerance
- Dec appetite but increased weight, slow feeding
- Constipation
- Menorrhagia
- Hoarse voice
- Dec memory, cognition, intellectual impairment (LD)
- Dementia
- Cramps
- Bradycardia
- Round puffy face, course facies, large tongue
- Prolonged neonatal jaundice
- Widely opened posterior fontanelle
- Hypotonia
- Pale, cold, mottled, dry skin
- Little hoarse crying
- Failure to thrive
How would you investigate Hypothyroidism?
Bloods = high TSH >20 mU/L, low T4
Thyroid Abs = anti-thyroid peroxidase Abs, antithyroglobulin Abs
X-ray L wrist + hand = examine ossification centre
How would you manage hypothyroidism?
Levothyroxine - 1.6mcg/Kg/day
Aim TSH: 0.5-2.5 mU/L
Preg = increase by at least 25-50 micrograms levothyroxine
NEONATE = Levothyroxine - 15mcg/kg/d, adjust by 5mcg every 2w to typical dose of 20-50mcg
<2ys = 5mcg/kg/d, adjust 10mcg every 2-4w
> 2ys = 50mcg, adjust 25mcg every 2-4w
SE = ◦ Arrhythmia (cardiac disease, severe, >50 - starting dose 25mcg, dose slowly titrated) ◦ Hyperthyroidism ◦ Reduced bone mineral density ◦ Worsening angina ◦ AF
Advice = take 45-1hr mins before breakfast (morning), can only drink water with tablet
If forget to take dose - take 2 tablets the next day
Also monitor TFT every 8-12 weeks
What are the complications of hypothyroidism?
Goitre
Depression
HF
Coma
Delayed puberty
Shorter in height
Developmental delays
Outline Hashimotos
Autoimmune
NON PAINFUL Goitre
Anti-thyroid peroxidase, anti-Tg Ab
More common in women
Outline Sub acute - De-Quervains hypothyroidism
Follows a viral infection
Typically presents with hyperthyroidism
- Phase 1 = hyper, PAINFUL goitre, raised ESR
- Phase 2 = euthyroid
- Phase 3 = hypothyroidism
- Phase 4 = thyroid structure/function back to normal
Investigations
• Reduced uptake on iodine 131-scan
Management
• Self limiting
• Pain = aspirin, NSAIDs
• Steroids
Outline congenital hypothyroidism
If not Dx and treated in the first 4 weeks it causes irreversible cognitive impairment
Prolonged neonatal jaundice
Delayed mental + physical milestones
Short stature
Puffy face, macroglossia
Hypotonia
Screened using heel prick test
