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Flashcards in PBL 3 - Hypothyroidism Deck (13)
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1

What are the causes of hypothyroidism? (7)

1. Autoimmune (90%)
a. Hashimoto's thyroiditis
b. Spontaneous atrophic hypothyroidism

2. Iatrogenic
a. Radioactive iodine treatment
b. Thyroidectomy
c. Other thyroid drugs

3. Transient thyroiditis

4. Iodine deficiency

5. Congenital
a. Thyroid aplasia

6. Infiltrative
a. Amyloidosis
b. Sarcoidosis

7. Secondary hypothyroidism
a. TSH deficiency

2

Describe the pathophysiology of hypothyroidism. (3)

1. Insufficient thyroid hormones

2. Effect of decreased thyroid hormones:
a. Decreased metabolism
b. Myxoedema

3. Mexoedematous coma
a. Carbon dioxide retention and coma
b. Fluid and electrolyte imbalance
c. Hypothermia

3

Describe the symptoms of hypothyroidism. (9)

1. Weight gain

2. Facial features:
a. Purplish lips
b. Malar flush
c. Periorbital oedema
d. Loss of lateral oedema

3. Cold intolerance
4. Fatigue
5. Dry skin
6. Dry hair
7. Menorrhagia
8. Depression
9. Psychosis

4

Describe the clinical signs of hypothyroidism. (10)

What is the pnemonic?

"BRADYCARDIC":

Bradycardia
Reflexes slow (hyporeflexia)
Ataxia (cerebellar)
Dry, thin hair/skin
Yawning/drowsy/coma
Ascites and non-pitting oedema
Round, puffy face
Defeated demeanour
Immobile/ileus
Chronic heart failure

5

List the investigations that can be done for hypothyroidism. (2)

1. TSH levels
2. Free serum T4 levels

6

Define Hashimoto's thyroiditis.

Chronic inflammation of the thyroid gland due to the formation of antibodies against normal thyroid tissue

7

Describe the pathophysiology of Hashimoto's thyroiditis. (2)

1. Total destruction of the thyroid due to an immunological process

2. Autoantibodies are produced and act against the thyroid
a. Anti-thyroid peroxidase (anti-TPO) Ab
b. Anti-nuclear factor
c. Anti-TSH receptor antibodies

8

Describe the treatment of hypothyroidism. (1)

What are the side effects? (2)

What are the contraindications? (3)

Levothyroxine

SIDE EFFECTS:
Increased risk of osteoporosis
Atrial fibrillation

CONTRAINDICATIONS:
PPIs
Ferrous sulphate
Calcium supplements

9

List 5 causes of congenital hypothyroidism.

Thyroid dysgenesis, e.g.
-Abnormal TSH receptor

Dyshormonogenesis, e.g.
-Thyroid peroxidase
-Thyroglobulin
-Sodium iodide symporter
-Pendrin

10

What is Pendred syndrome?

Congenital hypothyroidism due to abnormalities in pendrin

11

Describe the clinical features of congenital hypothyroidism (cretinism). (9)

Coarse facial features
Macroglossia
Large fontanelles
Umbilical hernia
Mottled/cool/dry skin
Developmental delay
Pallor
Myxoedema
Goitre

12

What is hypothyroidism associated with? (6)

Other autoimmune diseases, e.g.
-T1DM
-Addison's disease
-Pernicious anaemia
-Vitiligo

Genetic disorders, e.g.
-Down's syndrome
-Turner's syndrome

13

What do you call iodine induced hypothyroidism?

Wolff Chaikoff effect