Thyroid Disease Flashcards
Features + rx of Subacute granulomatous thyroiditis
(viral infection, painful thyroid)
NSAIDs
Rx + monitoring of hypothyroidism
Levothyroxine treatment of choice, start 12.5-50mcg/day
Repeat TSH q3-4 months until stable, then yearly
Myxedema coma sx
Altered mental status, hypoventilation, hypothermia, hypotension, bradycardia, hyponatremia, hypoglycemia
Rx of myxedema coma
Levothyroxine (T4) loading dose 200-400mcg IV, then 1.6mcg/kg/day IV
Liothyronine (T3) 5-20mcg followed by 2.5-10mcg q8h given with T4
Glucocorticoids (hydrocortisone 100mg IV q8-12h x2d) until coexisting adrenal insufficiency can be excluded
Supportive measures (ventilation, fluids, correction of hyponatremia and hypothermia)
What are the receptor ab for Graves?
Graves (TSH receptor antibodies=TRAb)
Causes of thyroid storm?
Trauma, surgery, RAI
Sx of thyroid storm
Hyperthermia, tachycardia, N/V/D, dehydration, delirium, coma
Treatment of thyroid storm
B-Blockers (Propranolol 60-80mg q4-6h)
Propylthiouracil 200mg PO q4h
Iodine solution (delayed 1h after PTU)
Iodinated radiocontrast
High-dose IV hydrocortisone 100mg IV q8h
RF for hyperthyroidism
Diffuse/ nodular goitre
T1DM
Autoimmune disorder
Fam hx
Amiodarone, lithium, iodide
When to check TSH
After med dose changes
Before initiating treatment
Periodically in stable pts
rx for hyperthyroidism
Propranolol 10-40mg QID
Methimazole 5-120mg for 12-18mo then taper + DC
Radioactive iodine - single dose
Subtotal thyroidectomy - treatment of choice in pregnancy + pts <40 y/o
Precipitants of hyperparathyroidism
thiazide diuretics, lithium, RT, MEN type 1 + 2a
Lab results for hyperparathyroidism
high calcium, high PTH, low phosphate, high ALP
Sx of hyperparathyroidism
bone pain, fragility fractures, kidney stones, polyuria, N/V, constipation, lethargy, depression, gout, reduced BMD
Rx of hyperparathyroidism
parathyroidectomy, volume repletion + loop diuretics, pamidronate
Causes of hypothyroidism
Chronic autoimmune thyroiditis (Hashimoto’s)
Postpartum thyroiditis
Iodine deficiency
Drugs: amiodarone, lithium, iodine
Central hypothyroidism
Pituitary adenoma or damage
Infiltrative: sarcoidosis, TB, granulomas)
Who is at risk of hypothyroidism?
Women >45
1st trimester pregnancy
Trying to conceive
Post partum (6w-6mo)
Elderly
FHx
Autoimmune disease
Neck RT
Ix for hypo
High TSH + low free T4 = hypothyroidism
Normal/ low TSH + low free T4 = central hypothyroidism
T3 if undetectable TSH + normal T4
Thyroid scan or MRI thyroid if goitre present
RF for hyper
Diffuse/ nodular goitre
T1DM
Autoimmune disorder
Fam hx
Amiodarone, lithium, iodide
Causes of hyper
Graves (antibody against TSH receptor) (High uptake, diffuse)
Toxic multinodular goitre (high uptake, nodular)
Toxic adenoma (high uptake, one ‘hot’ area)
Thyroditis (low uptake)
Treatment induced
Thyroid cancer
Sx of hyper
Wt loss, heat intolerance
Lid lag, proptosis, periorbital edema, hair loss, goiter, thyroid bruits
Palpitations, tachy, AF, wide pulse pressure, HTN
Tremor, edema, pretibial myxedema, muscle weakness
Amenorrhea
Ix for hyper
Low TSH high T4
MRI if high TSH + T4 (suspect TSH secreting pituitary adenoma)
Thyroid uptake if low TSH + high free T4
CBC and LFT at BL
Lab results for thyroid storm
low TSH, high free T4, low Hb, high WBC, high glucose, high calcium, high LFTs
Causes of hypo
Chronic autoimmune thyroiditis (Hashimoto’s)
Postpartum thyroiditis
Iodine deficiency
Drugs: amiodarone, lithium, iodine
Central hypothyroidism
Pituitary adenoma or damage
Infiltrative: sarcoidosis, TB, granulomas)
RF for hypo
Women >45
1st trimester pregnancy
Trying to conceive
Post partum (6w-6mo)
Elderly
FHx
Autoimmune disease
Neck RT
Sx of hypo
Fatigue, weakness, cold intolerance, weight gain
Depression, memory loss
Enlargement of tongue, hoarseness, goitre
Bradycardia, pericardial effusion, HTN, CHF
Muscle weakness
Constipation
Paresthesia, muscle cramps
Menorrhagie, amenorrhea, impotence
Periorbital edema, hair loss, lateral ⅓ eyebrow thin, brittle nails
Anemia
Ix for hypo
High TSH + low free T4 = hypothyroidism
Normal/ low TSH + low free T4 = central hypothyroidism
T3 if undetectable TSH + normal T4
Thyroid scan or MRI thyroid if goitre present
Management of Subclinical hypothyroidism
No treatment if TSH <10, normal T4, asymptomatic, not pregnant
Most normalize over next 5 yrs
Monitor annually
Treat w/ levothyroxine if:
Elevated TPO antibodies
Goitre
Fam hx of autoimmune dz
Pregnancy
Rx for hypo
Tx if
TSH >10 + symptomatic
TSH 5-10 AND:
Elevated TPO antibodies
Goitre
Fam hx of autoimmune dz
Pregnancy
What are the features of + when do you Rx: Subacute granulomatous thyroiditis
(preceding viral infection, painful thyroid) = usually self resolves, treat w/ NSAIDs
Advice for pts on levo
Absorption affected by: high fibre, soy, coffee, calcium, iron, antacids, PPI, anticonvulsants
Take on empty stomach 30 mins before breakfast
Thyroid storm Rx
thionamides e.g. methimazole (blocking synthesis), propranolol, iodine, bile acid sequestrant (cholestyramine)
Rx for graves
thionamides e.g. methimazole (blocking synthesis), propranolol, iodine, bile acid sequestrant (cholestyramine), radiation, thyroidectomy
When to screen for hypothyroidism
sx, at risk (pregnancy, prev thyroid dz, prev radiation, pituitary disorder), taking replacement
Next steps if hyperthyroid on labs
BB 6-8 wks, radioactive iodine uptake (unless Graves or pregnant or breastfeeding)
thyroid nodule workup
TSH, thyroid US (>1cm, taller than wide), FNA for cytology)
What are features of a suspicious thyroid nodules?
> 1cm, irregular surface, taller than wide, calcifications
Hypothyroidism signs
dry skin, bradycardia, wt gain, delayed reflex relaxation, edema
Hyperthyroidism signs
diaphoresis, tachycardia, wt loss, goiter, tremor, thinning of hair, lid lag, exophthalmos
