FN: Hypothyroidism

Question 1

Epi

Answer 1

4/1000/yr
Sex: F»M = 6:1
Age: >40yrs

Question 2

Symptoms

Answer 2

Letheragy
Cold intolerance
reduced appetite and weight ain
constipation
Menorrhagia
reduced mood

Question 3

Signs

Answer 3

Cold hands
Bradycardic
Slow-relaxing reflexes
Dry hair and skin
Puffy face
Goitre
Myo[athy, neruopathy
Ascites
Myxoedema
1. SC tissue swelling in severe hypothyroidism
2. Typically around eyes and dorsum of hand

Question 4

Causes

Answer 4

Primary
Post surgical
Secondary

Question 5

Primary causes

Answer 5

Atrophic thyroiditis (commonest UK)
Hasimoto's thyroiditis
Subacute thyroiditis (e.g. post-partum)
Post De Quervains thyroiditis
Iodine deficiency (commonest worldside)
Drugs: carbimazole, amiodarone, lithium
Congenital: thyroid agenesis

Question 6

Post-surgical

Answer 6

thyroidectomy

Radioioding

Question 7

Secondary

Answer 7

Hypopituitarism (v.rare cause)

Question 8

Atrophic thyroiditis

Answer 8

1. Thyroid antibodies +ve: anti-TPO, anti-TSH
2. Lymphoctic infiltrate –> atrophy (no goitre)
3. Associations

Question 9

Atrophic thyroiditis associatinos

Answer 9

Pernicious anaemia
Vitiligo
Endocrinopathies

Question 10

Hasimotos thyroiditis

Answer 10

TOP +ve
Atrophy + regeneration –> goitre
May go through initial thyrotoxicosis phase
May be euthyroid or hypothyroid

Question 11

Investigations

Answer 11

1. Raised TSH, reduced T3/T3
2. Raised MCV ± normochromic anaemia
3. raised triglyceride + raised cholesterol
4. Hyponatraemia (SIADH)
5. raised CK if assoc. myopathy
6. Abs: TPO, TSH

Question 12

Treatment

Answer 12

Levothyroxine

1. titrate to normalise TSH
2. Enzyme inducers raised thyroxine metabolism
3. Clinical improvement takes - 2wks

Check for other AI disease e.g. addison’s PA

Question 13

Myxoedema Coma features

Answer 13

looks hypothyroid
Hypothermia
Hypoglycaemia
HEart failure: bradycardia and reduced BP
Coma and seizures

Question 14

Myxoedema Coma precipitants

Answer 14

1. radioiodine
2. Thyroidectomy
3. Pituitary surgery
4. Infection, trauma, MI, stroke

Question 15

Myxoedema Coma management

Answer 15

Bloods: TFTs, FBC, U+E, glucose, cortisol
Correct any hypoglycaemia
T3T4 IV slowly (may ppt. myocardial ischaemia)
Hydrocortisone 100mg IV
Treat hypothermia and heart failure