Diagnostic Biochemistry of Endocrine Disorders Flashcards
What is the main biochemistry marker of choice to assess the thyroid gland?
1 - TSH
2 - T4
3 - T3
4 - TSH autoantibodies
1 - TSH
- thyroid stimulating hormone
- secreted by anterior pituitary gland
How much triiodothyronine (T3) and thyroxine (T4) are generally secreted daily?
- T4 = 100mcg/day
- T3 = 6mcg/day
In a 50 year old female who is tired, lethargic, has night sweats and some weight loss, with the following thyroid blood biochemistry results:
TSH: <0.01 mU/L 0.3- 4.2
FT4: 32 pmol/L 12- 22
FT3: 9 pmol/L 3.1- 6.8
Does this patient have hypo or hyperthyroidism?
- hyperthyroidism
- likely to be primary hyperthyroidism as TSH levels are low but still high T3 and T4
In hyperthyroidism, what happens to the functions of cells in the body?
- all cells go into over activation
- agitation, fine tremor, warm moist skin, palmar erythema
- sinus tachycardia, atrial fibrillation, heart failure, peripheral oedema
- muscle wasting, proximal myopathy, hyper-reflexia
- splenomegaly (enlarged spleen), lymphadenopathy (enlarged lymph nodes)
- gynaecomastia in men
- extrathyroid manifestations ofGraves’ (rare): thyroid acropachy, thyroid dermopathy.
What are the 5 main causes of hyperthyroidism, and which of these is most common?
1 - thyroid enlargement (a goitre)
2 - graves’ disease (autoimmune disease) - MOST COMMON
3 - toxic multinodular goitre: non-tender thyroid nodules
4 - toxic adenoma: unilateral, non-tender thyroid mass
5 - subacute thyroiditis:tender, firm, irregular, diffuse/asymmetric enlargement
6 - amiodarone-inducedthyroiditis (cardiac medication): small goitre usually present
If a patient has hyperthyroidism and you suspect Graves disease, what is the main antibody that needs to be assessed?
- thyroid stimulating hormone receptor antibody (TRaBs)
If a patient has hyperthyroidism and you suspect thyroiditis, what marker should be assessed?
- Pentraxin C-reactive proteins (CRP) an inflammatory marker
- thyroiditis is an inflammatory condition
If a patient has hyperthyroidism and you suspect postpartum thyroiditis, what marker should be assessed?
- TPOAbs (Thyroid peroxidase antibodies)
- thyroid peroxidase is used to create triiodothyronine (T3) and thyroxine (T4)
If a patient has hyperthyroidism which organ must be screened prior to starting any anti-thyroid medications?
- liver
- full blood count is also required
If a patient has hyperthyroidism and you suspect there may be an enlargement of the neck or a nodule, what would be the first imaging modality used?
- ultrasound
What is Euthyroid sick?
- eu = good/normal
- thyroid = thyroid gland
- abnormal findings on thyroid function tests occurring without thyroidal illness (NTI), without preexisting hypothalamic-pituitary and thyroid gland dysfunction
Euthyroid sick is when there is an abnormal findings on thyroid function tests occurring without thyroidal illness (NTI), without preexisting hypothalamic-pituitary and thyroid gland dysfunction
- eu = good/normal
- thyroid = thyroid gland
What states does this normally occur in?
- catabolic states (breakdown of larger molecules into smaller molecules for energy)
- starvation or severe illness
Euthyroid sick is when there is an abnormal findings on thyroid function tests occurring without thyroidal illness (NTI), without preexisting hypothalamic-pituitary and thyroid gland dysfunction
- eu = good/normal
- thyroid = thyroid gland
This normally occur in catabolic states (breakdown of larger molecules into smaller molecules for energy), such as starvation or severe illness. The body essentially shuts down energy dependent functions that it decides are not essential. There is an enzyme in the thyroid that is down regulated in catabolic states, that may account for the abnormal thyroid function. What is this enzyme?
- de-iodinase
- converts thyroxine (T4) into the active form of triiodothyronine (T3)
Should we measure thyroid function in a sick patient with suspected Sick Euthyroid?
- no
- thyroid hormone decreases, but then rebounds in Sick Euthyroid
- it is difficult to determine what point they are at, so measurement of thyroid gland may be pointless
The adrenal gland is part of the hypothalamic pituitary adrenal axis. What does the hypothalamus and in turn the pituitary gland secrete to stimulate the adrenal glands?
- hypothalamus secretes corticotropin-releasing hormone
- pituitary gland secretes adrenocorticotropic hormone
The adrenal gland has 2 main parts, the medulla and the cortex. What are main molecules that the medulla secretes?
- catecholamines
1 - adrenaline
2 - noradrenaline
3 - dopamine
The adrenal gland has 2 main parts, the medulla and the cortex. The cortex can be further divided into 3 parts, label the image below using these labels:
zona reticularis
zona glomerulosa
zona fasciculata
1 = zona glomerulosa (outermost layer) 2 = zona fasciculata (middle layer) 3 = zona reticularis (innermost layer)
The adrenal gland has 2 main parts, the medulla and the cortex. The cortex can be further divided into 3 parts, using GFR:
1 = zona glomerulosa (outermost layer) 2 = zona fasciculata (middle layer) 3 = zona reticularis (innermost layer)
What does the phrase the deeper you get the sweeter it gets mean in relation to what the adrenal gland secretes?
- zona glomerulosa (outermost layer) = salts (mineralocorticoids = Aldosterone)
- zona fasciculata (middle layer) = sugar (Glucocorticoids = cortisol)
- zona reticularis (innermost layer) = sex (Androgens = Dehydroepiandrosterone)
The adrenal gland has 2 main parts, the medulla and the cortex. The cortex can be further divided into 3 parts, using GFR we can remember them, and see here examples of what each layer secretes:
- zona glomerulosa (outermost layer) = salts (mineralocorticoids = Aldosterone)
- zona fasciculata (middle layer) = sugar (Glucocorticoids = cortisol)
- zona reticularis (innermost layer) = sex (Androgens = Dehydroepiandrosterone)
Why are mineralocorticoids, called mineralocorticoids?
- mineral = as they are involved in maintenance of salts in the body (aldosterone)
- corticoid = steroid
The adrenal gland has 2 main parts, the medulla and the cortex. The cortex can be further divided into 3 parts, using GFR we can remember them, and see here examples of what each layer secretes:
- zona glomerulosa (outermost layer) = salts (mineralocorticoids = Aldosterone)
- zona fasciculata (middle layer) = sugar (Glucocorticoids = cortisol)
- zona reticularis (innermost layer) = sex (Androgens = Dehydroepiandrosterone)
Why are glucocorticoids, called glucocorticoids?
- gluc = glucose
- corticoid = steroid
- cortisol is an example
The adrenal gland has 2 main parts, the medulla and the cortex. The cortex can be further divided into 3 parts, using GFR we can remember them, and see here examples of what each layer secretes:
- zona glomerulosa (outermost layer) = salts (mineralocorticoids = Aldosterone)
- zona fasciculata (middle layer) = sugar (Glucocorticoids = cortisol)
- zona reticularis (innermost layer) = sex (Androgens = Dehydroepiandrosterone)
Why are androgens, called androgens?
- andr = greek for man
- hormones involved in reproduction
The adrenal gland has 2 main parts, the medulla and the cortex. The cortex can be further divided into 3 parts, using GFR we can remember them, and see here examples of what each layer secretes:
- zona glomerulosa (outermost layer) = salts (mineralocorticoids = Aldosterone)
- zona fasciculata (middle layer) = sugar (Glucocorticoids = cortisol)
- zona reticularis (innermost layer) = sex (Androgens = Dehydroepiandrosterone)
What is Addisons disease also called adrenal insufficiency?
- problem is in adrenal gland
- lack of cortisol and aldosterone
Addisons disease, also called adrenal insufficiency is a problem is in adrenal gland, causing a lack of cortisol and aldosterone secretion. What is the most common cause of this?
1 - tumour
2 - autoimmune
3 - low cholesterol levels
4 - infection
2 - autoimmune disease
What is secondary adrenal insufficiency?
- a problem not in the adrenal gland
- likely to be in the pituitary gland which releases adrenocorticotropic hormone (ACTH)
- causing a lack of cortisol only as this is stimulated by ACTH