Pathophysiology Of Thyroid Dysfunction( Chemical Pathology) Flashcards

1
Q

What tests are used for thyroid function? And how do we diagnose based on them?(3)

A

1.Testing for TSH levels:
• It is decreased in hyperthyroidism.
• It is increased in hypothyroidism.
2. Total T3 and T4
3. Free T3 and T4

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2
Q

Major binding protein for T3 and T4

A

Thyroxine binding globulin

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3
Q

Most abundant binding protein for T3 and T4

A

Albumin

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4
Q

What are some of the causes of low TSH in clinically euthyroid patients?

A

Pregnancy
Subclinical hyperthyroidism
Treated hyperthyroidism( first 6 months)
Ophthalmic grave’s disease
Nonthyroidal illness
Treatment with dopaminergic drugs or high dose glococorticoids

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5
Q

What are causes of high TSH in some clinically euthyroid patients?(2)

A

Subclinical hypothyroidism
Recovery phase of nonthyroidal illness

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6
Q

Causes of hyperthyroidism, define the terms(5)

A

•Graves disease- autoimmune, TSH receptor stimulating antibodies.
•Trophoblastic- Secretion of high hCG which mimics the effects of TSH.
•Fractitious- Exogenous administration of T4.
•Iodine-induced
•Thyroiditis:-Transient phenomenon resulting from release of stored T4 from damaged thyroid gland.

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7
Q

How can we manage hyperthyroidism(NB)

A

Carbimazole
Radioiodine
Thyroidectomy

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8
Q

What provides the best indicator for thyroid status in the early months of hyperthyroidism treatment?

A

Free T4

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9
Q

What are some of the causes of hypothyroidism?

A

IATROGENIC:
-Radioactive iodine
-Thyroidectomy
CONGENITAL:
-Iodine deficiency
SECONDARY
-Hypopituitarism
-Hypothalamic dysfunction
Hashimoto’s thyroiditis
Atrophic thyroiditis
Post-partum thyroiditis

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10
Q

Management of hypothyroidism(NB)

A

T4 replacement therapy

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11
Q

What is the condition for replacing T4 in subclinical hypothyroidism

A

TSH>10mu/L

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12
Q

When are Thyroid Function Tests(TFT) unreliable?(4)

A

-Nonthyroidal illness
- Neonate
- Pregnancy
- Recovery from illness

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13
Q

What are the tests affected by hyperthyroidism?(4)

A

Hyperglycaemia
Hypocholesterolaemia
Abnormal liver function test
Hypercalcaemia

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14
Q

What are the tests affected by hypothyroidism?(3)

A

Hyponatraemia
Hypercholesterolaemia
Hyperprolactinaemia

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15
Q

What causes abnormal results ( hypothyroidism) in euthyroid patients?(3)

A

Abnormal Thyroxine Binding Globulin.
Genetic variants of albumin and pre-albumin.
Assay interference

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16
Q

What are other tests than can be taken for hypothyroidism?(3)

A

Thyroid-Releasing Hormone test
AntiTPO
TRAbs