Week 3 - E - Week 3 - hypo/hyper thyroidism and thyroiditis, sick-euthryoid Flashcards
Autoimmune thyroid disease is the commonest cause of primary hyper and hypo thyroidism Where do the causes for secondary hypo and hyper thyroidism arise?
Primary hypo/hyperthyrodisim is due to a problem with the thyroid gland
Secondary hypo/hyperthyroidism - They arise due to problems in the hypothalamus or the pituitary gland
When measuring hromones to test for thyroid disease, what are the hormone levels in overt (clincal) hyperthyroid disease?
TSH - low
T4/T3 - high
When measuring hormones to test for thyroid disease, what are the hormone levels in overt (clincal) hypothyroid disease?
TSH - high (compensting for low T4/T3)
T4/T3 - low (failing thyroid gland)
What are the hormone levels in both secondary hypo and hyper thyroidism?
Hyperthyroidism - TSH is high and T4/T3 is high
Hypothyroidism - TSH is low and T4/T3 is low
What is one cause of secondary hyperthyroidism? (thyrotropinoma) What is one cause of secondary hypothyroidism?
Secondary hyperthyroidism - a rare pituitary tumour that secretes TSH - known as a TSH oma (or thyrotropinoma)
Secondary hypothyroidism - pituitary gland failure
What is the difference between overt (clinical) and subclinical thyroid disease?
Overt thyroid disease is defined as the clincal syndrome with associated hormones elevated and decreased
Subclinical thyroid disease is defined as thyroid hormones (T3/4) within normal range however TSH out of the normal range
* there may or may not be symptoms of thyroid disease
In subclincial hypo/hyper thyroidism, what are the hormone levels?
Hypothyroidism - TSH is high with T4/3 normal
Hyperthyroidism - TSH is low with T4/3 normal
Why are the thyroid hormone levels normal in subclinical hypo or hyper thyroidism?
In sublcinical hyperthyroidism - the T4 and T3 hormone levels are rising however still within the normal range and therefore the TSH levels falls in an attempt to prevent this
In subclincal hypothyroisim, the thyroid hormone levels are falling within the normal range and TSH increases in an attempt to prevent overt hypothyroidims
What is the term used synonymously with severe hypothyroidism but also refers to the dermatological changes that can occur in hypothyroidism?
Myxoedema
What causes myxoedema? How does it appear on a person?
accumulation of mucopolysacchardies in connective tissue of dermis causing swelling of the skin and underlying tissues giving a waxy consistency
What is the most severe form of hypothyroidism? What are its features?
Myxoedema coma - the body temperature is usually abnormally low
sparse, dry hair, and loss of the outer thirds of the eyebrows;
difficulty breathing;
significant swelling (edema) all over the body with swollen eyes and thickening of the tongue,
Form of thyroid dermopathy in grave’s disease seen on anterior aspect of the shin?
Pretibial myxoedema
Aspect of Grave’s disease characterized by soft-tissue swelling of the hands and clubbing of the fingers?
Thyroid acropachy
What is the most common cause of primary hypothyroidism? (in the western world) What defieciency can lead to hypothyroidism? (can also be due to excess of this mineral)
hashimoto’s thyroidits (autoimmune thyroiditis)
(worldwide iodine deficiency is the most common cause)
Iodine deficiency
What is the most common drug induced form of hypothyroidism?
Amiodarone
Secondary cause of hypothyroidism caused by an infilrative disease What is this disease?
Sarcoidosis
What is a secondary cause of thyroid disease which can occur due to women who lose a life-threatening amount of blood in childbirth or who have severe low blood pressure during or after childbirth, which can deprive the body of oxygen?
This condition is known as Sheehan syndrome - where excessive blood loss in childbirth can deprive the body of oxygen.
This lack of oxygen that causes damage to the pituitary gland
It results in panhypopituitarism - ‘pan’ referring to all pituitary hormones being affected
Which antibody is most commonly raised in people suffering from hypothyroidism?
Anti-thyroid peroxidase antibodies (Anti-TPO)
What is another autoimmune condition that may be present in those with Hashimotos disease? A cutaneous conditions
Vitiligo
What are symptoms of hypothyroidism in the eyes and hair? What can hypo do to heart failure? (what is the symptom)
Eyes - periorbital puffiness
Hair- dry and coarse
Hypothyroidism can worsen heart failure causing pitting oedema
What does hypothyroidism do to the metabolism and what does this cause?
Slows the metabolism and decreases basal metabolic expenditure
It decreases the appetite however still causes a weight gain usually
Due to the swelling caused by hypothyroidism, what syndrome can this cause in rare cases associated with nerve compression?
Carpal tunnel syndrome
Hypothyroidism can cause oligo/amenorrhea How does hypothyroidism cause galactorrhea?
Hypothyroidism will give feedback loops causing TRH to secrete more TSH
however TRH also causes the release of prolactin and therefore due to the rise in prolactin, galactorrhea may occur
In treating hypothyroidism, what medication and dosage should the patient be started on?
Younger patients: start thyroxine at 50-100 μg daily
In the elderly with a history of IHD: start thryroxine at 25-50 μg daily