Endocrinology 2 Flashcards
If high Sex hormone globulin - what is reduced?
Insulin
Androgen
FSH/LH
PCOS ultrasound findings?
12 follicles +/- string of pearls
1 ovary > 10 mls
Sex hormone globulin binding affinity?
Dihydrotestosterone the most!
Testosterone - 2nd
Estradiol - 3rd
COCP does what?
Increase SHBG - bind to estradiol ( ovaries androgen)
What can be given to induce ovulation?
Letrozole (1st line)
Clomiphene (2nd line)
Hypothalamic amenorrhoea (Tertiary) causes?
Intense exercise - Female athlete triad
—–Amenorrhea + Reduced bone density due to eating disorder
Reduce weight/calorie intake = reduced leptin
High stress - Cortisol inhibit GnRH
Biotin cause false Hyperthyroidism (Graves presentation) why?
Biotin bind to Streptavidin site = thyrotrophin (TSH) can’t bind and signal it = so low TSH (falsely low)
No signal so all Free T4 roams around = so high T4 (falsely high)
How clexane affects Thyroid hormone long term?
Displace T3/4 from binding proteins = low T3/4
How does anticonvulsants affect thyroid hormone?
Hypothyroidism - induce high thyroid hormone metabolism
How does lithium affect thyroid hormone?
Lithium reduces pinocytosis process - so thyroid hormone stays in colloid = goitre
When do thyroidectomy?
Large goitre + obstruction
Active Graves’ opthalmopathy
Co-existing Hyper parathyroidism
Thyroid malignancy
When do RAI?
Relapse post anti-thyroid medications
Poor surgical candidate
Doesn’t want children / breast-feeding
what happens in sick euthyroidism?
Low T3 syndrome
-Rapid inhibition of D1 - drops T3
T4/TSH normal but if goes on - T4/TSH drops as well
Causes of secondary hyperthyroidism?
Assay interference - main cause
IF assay interference ruled out;
TSHoma/ Thyroid hormone resistance
Medications to prevent DM retinopathy?
Anti-VEGF therapy
Fenofibrate