Management of thyroid disorder Flashcards
What is thyrotoxicosis?
- Excess in T3 and T4 concentration in serum, due to the release of intrathyroidal thyroid hormone
- Excess thyroid hormone exposure and action on tissues
What is hyperthyroidism?
Excess thyroid hormone production and release
What is overt hyperthyroidism?
Hyperthyroidism + thyrotoxicosis
- Thyrotoxicosis is the term used when there is an excess amount of T3 and T4 in the blood regardless of the cause/ origin – the body manifests signs and symptoms due to this increased level
What is subclinical hyperthyroidism?
hyperthyroidism without thyrotoxicosis
What is a thyroid storm (thyrotoxic crisis)?
- Extreme exacerbation of thyrotoxicosis
- Medical emergency characterized by a severe acute exacerbation of the signs and symptoms of hyperthyroidism
- Fever, tachycardia out of proportion to the fever, altered mental status, diarrhea, vomiting, and cardiac arrhythmia
- It could also cause shock, stupor, coma, and death
What is hypothyroidism?
- When the thyroid gland does not produce enough thyroid hormone
- Abnormally low level of circulating thyroid hormones
What are the thyroid function tests?
1) TSH
2) Thyroid hormone (T3 & T4)
3) Anti-TSH
4) Anti-TPO
5) Thyroid ultrasound
6) Thyroid scan
7) Thyroid uptake
8) Fine needle aspiration
What are the thyroid function tests?
1) TSH (increased in case of hypothyroidism when T3 & T4 levels levels are decreased)
2) Thyrotropin-releasing hormone (BLOOD LEVELS OF IT ARE RARELY USED, TRH is not a routine test – he said in the exam if one of the choices he puts as TRH do not choose it)
3) T3 & T4 (thyrotoxicosis is detected when they are both elevated)
What are the levels of the thyroid hormones in secondary hyperthyroidism?
1) Increased TSH and T3 & T4
What are the thyroid hormone blood levels in case of tertiary hyperthyroidism?
Increased T3 & T4, TSH and TRH
What are the different investigations of autoantibodies for the thyroid gland?
1) Thyroglobulin antibody (TGAb)
2) Thyroid peroxidase antibody (TPOAb)
3) Anti-TSH receptor antibodies (TSHrAb)
- Stimulating one is (TSAb)
- The blocking one is (TBAb)
Which thyroid autoantibodies is used in case of graves disease?
TSAb (thyroid-receptor-stimulating antibody)
- TRAb
Which thyroid autoantibodies is used in hashimotos?
TPOAb (Thyroid peroxidase antibody)
- Anti-TPO
What are the imaging investigations?
1) US (opportunity for fine needle aspiration)
2) Thyroid scan
3) Thyroid radioactive iodine uptake
What is a thyroid scan?
- Nuclear medicine test
- This thyroid scan (nuclear medicine test) is required to distinguish the subtypes, tells the underlying disease that causes the conditions
- On administering pertechnetate both lobes of the thyroid gland should diffusely glow up in the imaging as both the lobes take up the nuclear dye
- If it is darker than normal – suggests the thyroid gland is over-working
It can be irregular with hot spots (areas that take up more dye) – so they are over-working - This test can help us distinguish between diffuse hyperthyroidism (A) or a particular hot spot (D) – both of which will cause primary hyperthyroidism
- If in the scan the thyroid takes up the dye but there is a focal area that does not take up the dye (cold nodule) - this could be thyroid cancer
Describe the thyroid radioactive iodine uptake test
Measuring the amount of iodine (radioactive tracer) uptake by the thyroid gland
- The radiotracer is given to the patient IV or Oral
Describe the thyroglobulin test
Thyroglobulin is a substrate for the synthesis of thyroid hormone (T4 & T3), AS WELL AS THE STORAGE OF INACTIVE FORM OF THYROID HORMONE AND IODINE WITHIN THE FOLLICULAR LUMEN O A THYROID FOLLICLE
- Mostly used as a tumor marker (A reliable marker to see if there is a recurrence of cancer)
Which investigation is used as a tumor marker?
Thyroglobulin test
What classification of thyroid hormone disorders is based on increased thyroid stimulating hormone levels?
- Increased TSH:
1) Decreased T4 will be primary hypothyroidism (like in autoimmune thyroiditis)
2) Normal TSH will be subclinical hypothyroidism
3) Increased TSH will be secondary hyperthyroidism (like in a pituitary-secreting adenoma)
What classification of thyroid hormone disorders is based on normal thyroid stimulating hormone levels?
- Normal TSH:
1) Decreased T4 will be secondary hypothyroidism (like in non-secreting pituitary adenoma)
2) Normal TSH will be normal
3) Increased TSH will be secondary hyperthyroidism (like in TSH secreting pituitary adenoma)
What classification of thyroid hormone disorders is based on decreased thyroid stimulating hormone levels?
- Decreased TSH:
1) Decreased T4 will be secondary hypothyroidism (like in non-secreting pituitary adenoma)
2) Normal, T3 toxicosis
3) Increased TSH will be primary hyperthyroidism (like in graves disease)
