21. Hypothyroidism

Question 1

Outline the aetiology of hypothyroidism

Answer 1

Congenital = athyreosis, thyroid dysgenesis, dyshormonogenesis

Acquired = prematurity, hashimoto’s thyroiditis, hypopituitarism, trisomy 21

Question 2

What are the signs and symptoms of hypothyroidism?

Answer 2

• prolonged neonatal jaundice
• widely opened posterior fontanelle
• poor feeding
• hypotonia
• dry skin
• inactivity
• sleepiness
• slow feeding
• little crying
• constipation

Question 3

How would you investigate Hypothyroidism?

Answer 3

Bloods = high TSH, low T4

Thyroid Abs = anti-thyroid peroxidase Abs, antithyroglobulin Abs

X-ray L wrist + hand = examine ossification centre

Question 4

How would you manage hypothyroidism?

Answer 4

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

Question 5

What are the complications of hypothyroidism?

Answer 5

Goitre

Depression

HF

Coma

Question 6

Outline Hashimotos

Answer 6

Autoimmune

NON PAINFUL Goitre

Anti-thyroid peroxidase, anti-Tg Ab

More common in women

Question 7

Outline Sub acute - De-Quervains hypothyroidism

Answer 7

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

Question 8

Outline congenital hypothyroidism

Answer 8

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

Question 9

Outline pendreds syndrome

Answer 9

Autosomal recessive

Bilateral sensorineural deafness

Mild hypothyroidism

Goitre

Def in organification of iodine = dyshormogenesis

Treat = hormone replacement