Case 7 Thyroid Flashcards
(26 cards)
Which hormones are released from the anterior pituitary?
FSH, LH, ACTH, TSH, Prolactin, Endorphins, Growth hormone
Which hormones are released from the posterior pituitary?
ADH and oxytocin
Which hormone is released from the intermediate lobe of the pituitary?
Melanocyte Stimulating Hormone
Which hormones are released by the medulla of the adrenal gland?
Adrenaline and Noradrenaline
What are the three layers of the cortex of the medulla and what do they each release?
Glomerulosa, Fasciculata, Reticularis
Mineralcorticoids, Glucocorticoids, Androgens
What stimulates the release of TSH?
Anterior pituitary stimulation from TRH from hypothalamus
What is most T3 and T4 bound to?
Thyroxine binding globulin
What are the main functions of free T3 and T4?
Increase cell metabolism via cell receptors, growth and mental development, increase catechloamine effects
Which conditions is TBG low in?
Nephrotic syndrome and malnutrition (protein loss), drugs (androgens, corticosteroids, phenytoin), chronic liver disease and acromegaly
If hyperthyroid is suspected which TFTs should be performed?
TSH, T4 and T3
What will be the results of most hyperthyroid TFTs?
Low TSH and raised T4
Rare cases of TSH secreting pituitary adenoma will lead to raised TSH
When TSH, T4 and T3 levels are low what are the two possibilities? What should be done if these are the results?
Sick euthyroid or pituitary disease. Repeat after recovery from illness.
In Graves’, which antibody is increased?
TSH receptor antibody
Which autoantibodies are present in autoimmune thyroid disease?
Antithyroid peroxidase or antithyroglobulin antibodies may be elevated in Hashimoto’s or Graves’
Which test is used for monitoring carcinoma treatment and has low levels in factitious hyperthyroid?
Serum thyroglobulin
What is factitious hyperthyroidism?
Elevated thyroid hormone from taking too much thyroid medicine, accidentally or on purpose
What is the use of an ultrasound scan re thyroid?
Distinguishing cystic (usually benign) nodule from solid (possibly malignant) nodules. If a solitary or dominant nodule is present in a multi-nodular goitre, perform fine needle aspiration
What is an isotope scan useful for?
Hyperthyroid causes, detecting retrosternal goitre, ectopic thyroid tissue or thyroid metastases
When is surgery needed for suspicious nodules?
Rapid growth, compression signs, dominant nodule on scintigraphy, nodule larger than 3cm, hypo-echogenicity
What is thyrotoxicosis?
Clinical effect of excess thyroid hormone
What are the main symptoms of thyrotoxicosis (think increased metabolic rate)? (Rare ones?)
Diarrhoea, decreased weight with increased appetite, sweats, heat intolerance, palpitations, overactive tremor, irritability, labile emotions, oligomenhorrea
Rare: psychosis, chorea, panic, itch, alopecia, urticaria
What are the signs of thyrotoxicosis on examination?
Bradycardia, AF or SVT, warm moist skin, fine tremor, palmar erythema, thin hair, lid lag, lid retraction, goitre, thyroid nodules or bruit
What are the signs of Graves’ disease?
Eye disease (exopthalamos, opthalmoplegia)
Pretibial myoedema
Thyroid acropachy in extreme circumstances
What tests indicate thyrotoxicosis?
Low TSH with elevated T4 and T3
Perhaps mild normocytic anaemia
Mild neutropenia in Graves
Elevated ESR, Ca and LFT
