Hypothyroidism

Question 1

Define hypothyroidism

Answer 1

Clinical syndrome resulting from insufficient secretion of thyroid hormones

Question 2

Aetiology of primary hypothyroidism

general, 5 acquired, 2 congenital

Answer 2

(decreased thyroid hormone production)

Acquired
Hashimoto’s thyroiditis (autoimmune)
Iatrogenic (post surgery, radioiodine, hyperthyroid medication)
Severe iodine deficiency 
Iodine excess (Wolff-Chaikoff effect)
Thyroiditis

Congenital
Thyroid dysgenesis
Inherited defects in thyroid hormone biosynthesis

Question 3

Aetiology of secondary hypothyroidism

2

Answer 3

(5% of cases)

Pituitary & hypothalamic disease
Resulting in reduced TSH & TRH —> reduced stimulation of thyroid hormone production

Question 4

Epidemiology of hypothyroidism

prevalence, gender, age, location

Answer 4

0.1-2% of adults
6x more common in FEMALES
Most common age of onset > 40 yrs
Iodine deficiency seen in mountainous areas (e.g. Himalayas)

Question 5

Presenting symptoms of hypothyroidism

18

Answer 5

Insidious onset

Cold intolerance
Lethargy
Weight gain
Reduced appetite 
Constipation
Dry skin
Hair loss
Hoarse voice
Mental slowness
Depression
Cramps
Ataxia
Parasthesia
Menstrual disturbance (irregular cycles, menorrhagia)
History of surgery or radioiodine therapy for hyperthyroidism
Personal/FH of other autoimmune conditions (e.g. Addison’s, T1DM)
Myxoedema coma (when severe - usually seen in elderly)

Question 6

Presenting symptoms of myxoedema coma

6

Answer 6

hypothermia
hypoventilation
hyponatraemia 
heart failure
confusion
coma

Question 7

Signs of hypothyroidism on physical examination

5 groups

Answer 7

Hands
Head/neck/face
Chest
Abdomen
Neurological

Question 8

Signs of hypothyroidism on physical examination - hands

2

Answer 8

Bradycardia

Cold hands

Question 9

Signs of hypothyroidism on physical examination - head/neck/skin
(6)

Answer 9

Pale puffy face
Goitre
Oedema 
Hair loss
Dry skin
Vitiligo

Question 10

Signs of hypothyroidism on physical examination - chest

2

Answer 10

Pericardial effusion

Pleural effusion

Question 11

Signs of hypothyroidism on physical examination - abdomen

Answer 11

Ascites

Question 12

Signs of hypothyroidism on physical examination - neuro

2

Answer 12

Slow relaxation of reflexes

Signs of carpal tunnel syndrome

Question 13

Investigations for hypothyroidism

4

Answer 13

TFTs
FBC - may show normocytic anaemia
U&Es - may show low sodium
Cholesterol - may be high

Question 14

Management of hypothyroidism

2

Answer 14

Chronic

Myxoedema coma

Question 15

Management of hypothyroidism - chronic

1.3

Answer 15

Levothyroxine
25-200mcg/day
Rule out underlying adrenal insufficiency before stating thyroid hormone replacement —> can precipitate Addisonian crisis
Adjust dose based on clinical picture & TFTs

Question 16

Management of hypothyroidism - myxoedema coma

6

Answer 16

Oxygen
Rewarming
Rehydration
IV T4/3
IV hydrocortisone
Treat underlying cause (e.g. infection)

Question 17

Complications of hypothyroidism

2

Answer 17

Myxoedema coma

Myxoedema madness

Question 18

Prognosis of hypothyroidism

2

Answer 18

Lifelong thyroxine required

Myxoedema coma mortality = 80%