Endocrinology Flashcards
thyroid anatomy
art: inf / sup thyroid arteries
glandular prox: parathyroid glands = posterior
nervous prox: recurrent laryngeal nerve = lateral
thyroid function
=> T4/T3 (iodinated)
=> calcitonin
hyperthyroidism presentation
most commonly in adult women weight loss + ^ appetite HTN palpitations / ^ HR / AF warm peripheries pruritus anxiousness / irritability insomnia diarrhoea lid lag lid retraction only in Grave's disease
lid retraction pathophysiology
inflammation of orbital fatty tissues in the orbit due to autoimmune destruction
Grave’s disease pathophysiology
TSH receptor stimulating autoantibodies (TSHrAb)
> ^ thyroid stimulation > ^ => T4 /T3
hyperthyroidism investigations
^ T4 / T3 v TSH TPO antibodies TSHrAb thyroid USS
hyperthyroidism treatment
symptomatic = bisoprolol
carbimazole
definitive = radioactive iodine / thyroidectomy
carbimazole side effects
generalised rash
bone marrow suppression
> pancytopenia = unexplained sore throat / fever
primary hypothyroidism pathophysiology
Hashimoto’s = autoimmune pathology
TPO Ab regulated
primary hypothyroidism investigation
v T4 / T3 & ^ TSH
secondary hypothyroidism pathology
hypo-pituitary system pathology / dysfunction
secondary hypothyroidism investigations
-/v TSH & v T4 / T3
pituitary function / head CT
hypothyroidism presentation
fatigue bradycardia cold intolerance weight gain / ^ BMI myxoedema skin thickening constipation
hypothyroidism treatment
thyroxine replacement
v T4 even with thyroxine treatment? consider:
malabsorption (Coeliac’s, iron supplements etc.)
poor adherence
under replacement
thyroxine treatment side effects
over replacement (hyperthyroidism) osteoporosis (> ^ => calcitonin)
subclinical hypothyroidism
normal T4 / T3
v TSH
if asymptomatic = no treatment (just regular blood tests / f/u)
glucocorticoid example
cortisol
hypopituitary adrenal negative feedback cycle
stress / v cortisol / ^ CRH (from hypothalamus) + pituitary => ACTH
ACTH + adrenal glands => cortisol
cortisol - pituitary / hypothalamus
cortisol function
^ serum glucose
regulates metabolism
v inflammation
^ memory formation
cortisol fluctuation
^ @ 0800
v @ 0000
adrenal androgens example
testosterone
controlled by fluctuations of ACTH
mineralocorticoids example
aldosterone
RAAS negative feedback system
v blood volume / v GFR / hypOna / hypERka + kidneys (juxtaglomerular cells) => renin
renin + conversion of angiotensinogen > angiotensin I
lungs => ACE + conversation of Ag I > Ag II
Ag II + adrenals => aldosterone
aldosterone + ^ K loss / ^ Na retention
