Hypothyroidism Flashcards
what % of hypothyroidism cases are primary vs secondary in etiology
95% primary
5% secondary
primary causes of hypothyroidism
iatrogenic–> post ablative for grave’s disease, surgery
thyroiditis
drugs
environmental iodine deficiency
congenital
what are the types of thyroiditis that can result in hypothyroidism
hashimotos
post partum
irradiation
what drugs can cause hypothyroidism
lithium
ASA
PTU
what are some congenital causes of hypothyroidism
thyroid agenesis
thyroid dysgenesis
what are secondary causes of hypothyroidism
pituitary –> Sheehan’s syndrome, tumours
hypothalamic hypothyroidism
what are major things on history suggestive of hypothyroidism, or that you should ask about specifically if you suspect hypothyroidism
- fatigue–> do you feel tired all the time
- cold intolerance–> more or fewer clothes needed than rest of family?
- hoarseness–> any voice changes?
- depression
- weight gain
- amenorrhea
general things to ask on history for hypothyroidism
fatigue cold intolerance slowness hoarseness depression iodine deficiency
HEENT things to ask on history for hypothyroidism
eye changes, diplopia
neck mass
CVS things to ask on history for hypothyroidism
bradycardia
GI things to ask on history for hypothyroidism
anorexia–> appetite?
weight gain
constipation
GU things to ask on history for hypothyroidism
menorrhagia, amenorrhea, anovulatory cycles
neuro/MSK things to ask on history for hypothyroidism
paresthesias
muscle cramps or wasting
derm things to ask on history for hypothyroidism
dry skin, hair loss, thinned eyebrows, puffiness of face
focused physical exam for hypothyroidism
general–> psychomotor depression, hoarseness
vitals–> bradycardia, diastolic HTN
skin–> color, moisture
hair–> fine or thick hair, loss of eyebrow hair in the outer third especially
eyes–> lid lag, proptosis, periorbital edema
compete thyroid exam
neck–> cervical LAD
CVS–> AF, tachy, brady
MSK–> fine motor tremor, proximal weakness, pretibial edema, delayed relaxation phase of reflexes
what constitutes a complete thyroid exam
IAPP
inspect, auscultate, palpate, percuss
goiter
nodule
make them swallow
how are reflexes changed in hypothyroidism
delayed relaxation phase
what is the earliest and most sensitive indication of hypothyroidism
increased serum TSH
what other lab tests should be ordered, other than TSH, to work up hypothyroidism
free T4, T3
anti-TPO and anti-thyroglobulin antibodies (for hashimotos)
thyroid u/s
thyroid scan with radioactive iodine uptake
management of hypothyroidism
T4 (thyroid hormone) replacement with levothyroxine (synthroid)
starting dose 25-50 mcg/day
increase over 2 months
maintenance dose 75-150 mcg/day
what is the dose of synthroid post total thyroidectomy
1.7 mcg/mg
how do you treat myedema coma
rapid treatment
ABC, O2, IV
levothyroxine 500 mcg bolus then 100 mcg IV daily
hydrocortisone 100 mcg IV q6h
warming blankets
