Hypothyroidism

Question 1

Define Hypothyroidism?

Answer 1

The clinical syndrome resulting from insufficienct secretion of thyroid hormones

Question 2

What are the two types of Hypothyroidism?

Answer 2

Primary Hypothyroidism (decreased thyroid hormone production) - 95%
Secondary Hypothyroidism - 5% of cases

Question 3

What is the aetiology of Primary Hypothyroidism?

Answer 3

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 4

What is the aetiology of Secondary Hypothyroidism?

Answer 4

Pituitary and Hypothalamic Disease - Resulting in reduced TSH and TRH and, hence, reduced stimulation of thyroid hormone production

Question 5

What is the epidemiology of Hypothyroidism?

Answer 5

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

Question 6

What is the onset of Hypothyroidism?

Answer 6

Insidious Onset

Question 7

What are the presenting symptoms of Hypothyroidism?

Answer 7

Cold intolerance 
Lethargy 
Weight gain
Reduced appetite
Constipation
Dry skin
Hair loss
Hoarse voice 
Mental slowness 
Depression
Cramps
Ataxia 
Paraesthesia 
Menstrual disturbance 
Myxoedema coma

Question 8

What is the menstrual disturbance in Hypothyroidism?

Answer 8

Irregular cycles

Menorrhagia

Question 9

How does myxoedema coma occur in Hypothyroidism?

Answer 9

Severe Hypothyroidism usually seen in the elderly

Question 10

What are some of the associated symptoms with Myxoedema Coma with Hypothyroidism?

Answer 10

Hypothermia 
Hypoventilation
Hyponatraemia 
Heart Failure 
Confusion
Coma

Question 11

What sort of things do we ask for the history of Hypothyroidism?

Answer 11

History of surgery or radioiodine therapy for hyperthyroidism
Personal/family history of other autoimmune conditions (e.g. Addison’s, type 1 Diabetes Mellitus_

Question 12

What are the signs of Hypothyroidism on the hands?

Answer 12

Bradycardia

Cold Hands

Question 13

What are the signs of Hypothyroidism on the Head/Neck/Skin?

Answer 13

Pale puffy face
Goitre 
Oedema 
Hair Loss
Dry Skinn
Vitiligo

Question 14

What are the signs of Hypothyroidism on the chest?

Answer 14

Pericardial effusion

Pleural effusion

Question 15

What are the signs of Hypothyroidism on the abdomen?

Answer 15

Ascites

Question 16

What are the Neurological signs of Hypothyroidism?

Answer 16

Slow relaxation of reflexes

Signs of carpal tunnel syndrome

Question 17

What bloods might you do for Hypothyroidism and what might you see?

Answer 17

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

Question 18

What is the chronic management plan for Hypothyroidism?

Answer 18

Levothyroxine (25-200 mcg/day)

• Rule out underlying adrenal insufficiency before starting thyroid hormone replacement
• Thyroid hormone replacement in the context of adrenal insufficiency can precipitate an Addisonian crisis
• Adjust dose based on clinical picture and TFTs

Question 19

What is the management plan for Myxoedema Coma?

Answer 19

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

Question 20

What are the possible complications for Hypothyroidism?

Answer 20

Myxoedema coma
Myxoedema madness (psychosis with delusions and hallucinations or dementia)

Question 21

What is the prognosis for patients with Hypothyroidism?

Answer 21

Lifelong levothyroxine is required

Myxoedema coma mortality = 80%