Uro/Endo week: Thyroid Flashcards
Hormones released by posterior pituitary gland
- Oxytocin
* ADH
Hormones released by anterior pituitary gland
- TSH
- ACTH
- FSH & LH
- GH
- Prolactin
- Endorphins
6 hormones released by hypothalamus
- Thyrotropin RH
- Gonadotropin RH
- Growth hormone RH
- Corticotropin RH
- Somatostatin
- Dopamine
Describe the thyroid negative feedback loop
Hypothalamus releases TRH
Anterior pituitary gland releases TSH
Thyroid gland releases T3 and T4
Circulating levels of T3 and T4 downregulate hormone release from hypothalamus and anterior pituitary gland
Is T3 or T4 active form
T3
Symptoms of hyperthyroidism
- weight loss
- increased appetite
- heat intolerance
- irritability, palpitations
- sweaty skin
- diarrhoea
- exopthalmos
- irregular menses
Symptoms of hypothyroidism
- weight gain
- reduced appetite
- cold intolerance
- lethargy, depression
- dry skin, nails
- constipation
- hair loss
Questions to ask about in thyroid history
- weight changes
- appetite changes
- heat/cold intolerance
- lethargy vs irritability/palpitations
- sweaty vs dry skin
- constipation vs diarrhoea
- eye changes
- hair loss
- menstrual changes
- swelling
Is non-pitting oedema a sign of hyperthyroidism or hypothyroidism
Usually hypothyroidism.
Only exception: Graves (autoimmune hyperthyroidism)
Differentiating hyper and hypothyroidism in examination:
- goitre
- fast/slow reflexes
Goitre: both have
Fast reflexes: hyperthyroidism
Slow reflexes: hypothyroidism
(note: atrophic thyroiditis has no goitre)
What is thyroid acropachy and is it present in hyper/hypo thyroidism
- Swelling of soft tissue of hands
- finger clubbing
- commonly affects metacarpals
Sign of Graves (hyperthyroidism)
Pathophysiology of Hashimoto’s
- autoantibodies attack TSH receptors
- CD8 and CD4 activation lead to thyrocyte destruction
Pathophysiology of Grave’s
- thyroid stimulating immunoglobulins bind to TSH receptor
- increased T3 and T4 secretion
- negative feedback loop results in low TSH and high circulating T3 and T4
Specific diagnostic signs for Hashimoto’s
-Autoantibodies against TSH receptors
Specific diagnostic signs for Grave’s (including specific signs on examination)
- TSH receptor antibodies
- exopthalmos
- non-pitting oedema (pretibial myxodema)
Low TSH
High T4 and T3
–> hyper or hypothyroidism
Hyperthyroidism
Normal range of levels for
- TSH
- fT4
- fT3
TSH: 0.4-4.0
fT4: 10-25
fT3: 3.5-7.5
What is the diagnosis
high TSH, low T3, low T4
Primary hypothyroidism
What is the diagnosis
low TSH, low T3, low T4
Secondary hypothyroidism
What is the diagnosis
low TSH, high T3, high T4
Primary hyperthyroidism
What is the diagnosis
high TSH, high T3, high T4
Secondary hyperthyroidism
Hyperthyroidism diseases
- Graves
- Toxic multinodular goitre
- Toxic adenoma
- De Quervain’s thyroiditis (acute inflammation of gland from virus)
- Post-partum thyroiditis
Hypothyroidism diseases
- Graves disease post treatment
- Thyroiditis
- Iatrogenic – surgery, radiotherapy
- Congenital
- Iodine excess/deficiency
- Disease of increasing age
- Drug-induced
Which drugs induce hypothyroidism
Amiodarone
Lithium
Carbimazole
IFN
Which thyroid disorder might hoarse/ deep voice with associated with
Hypothyroidism
Which thyroid disorder might kyphosis and osteoporotic fractures be with associated with
Hyperthyroidism
When asking pt to swallow during thyroid exam, how to differentiate swellings, among:
- thyroid gland mass
- thyroglossal cyst
- lymph nodes
thyroid gland mass: moves with swallowing
thyroglossal cysts: moves with swallowing
lymph nodes: barely move with swallowing
When asking pt to stick out tongue during thyroid exam, how to differentiate swellings, among:
- thyroid gland mass
- thyroglossal cyst
- lymph nodes
thyroid gland mass: DO NOT MOVE
thyroglossal cysts: move upwards noticeably
lymph nodes: DO NOT MOVE
Briefly describe thyroid exam:
look palpate percuss auscultate special tests
LOOK
-general: lethargy, dry hair
- neck: ask to swallow and stick out tongue
hands: dry/sweaty skin, thyroid acropachy, tremor, feel pulse - face: pigmentation
- eyes: exopthalmos, H movement test, lid lag
PALPATE
- thyroid
- lymph nodes
- trachea
PERCUSS
-downwards from sternal notch (for goitre)
AUSCULTATE
-thyroid for turbulent blood flow
SPECIAL TESTS
- reflexes
- proximal myopathy
Which thyroid disorder might palmar erythema be with associated with
Hyperthyroidism
Which thyroid disorder might carpal tunnel syndrome be with associated with
Hypothyroidism
Problems with which structures would be the cause of secondary hyper/hypothyroidism
Hypothalamus
Pituitary gland
