thyroid axis Flashcards
what is hypothyroidism
*low activity of thyroid gland may be primary from gland itself 95%
*secondary due to pituitary disease( deficiency of TSH)
*tertiary due to hypothalamic disease (deficient TRH)
-both secondary and tertiary are associated with low free T4 and low TSH level
what are causes of hypothyroidism
1)hashimotos thyroiditis (main cause)
*autoimmune thyroiditis a hypothyroidism with goiter
*cell and antibody mediated destruction of thyroid tissue
*antibodies to thyroglobulin, thyroid peroxidase enzyme, or antibodies to block binding of TSH to receptor
2) latrogenic (2nd most common)
3) De quervains thyroiditis (subacute viral thyroisitis)
what is de quervains thyroiditis
-follows a viral illness , has a prodromal phase w fever and flu like illness
- may cause transient hyperthyroidism due to leakage of hormones followedd by euthyroid then hypothyroid state
in hashimotos disease what is the goiter like
rubbery, nontender, nodular
to investigate thyroid disorders
all disorders check TSH -high in primary and low in secondary/tertiary
serum free T4 level (will be low)
thyroid antibodies and other organ specific antibodies
what is the management of hypothyroidism
lifelong levothyroxine
what is euthyroid sick syndrome
T3 is low
reverse T3 is high
TSH is not high–> not real hypothyroidism
signs of hyperthyroidism related to graves
exophthalmos and ophthalmoplegia
pretibial myxedema
thyroid bruit
thyroid acropachy
what does thyroglobulin antibody detect
recurrence of thyroid cancer
what does thyroid stimulating immunoglobulin detect
confirms graves disease if not positive then thick of other causes of hyperthyroidism: toxic or multinodular goiter (only graves has TSH receptor antibody )
what does thyroperoxidase antibody detect
may be seen in graves disease but more in hashimoto thyroiditis
antithyroid drugs
thionamide
what is thyroid storm
life threatening thyrotoxicosis
untreated hyperthyroidism excess thyroid
what are causes of primary hyperthyroidism
tumor parathyroid adenoma
what are symptoms in hyperparathyroidism
stones, bones, groans , thrones, and psychiatric overtones
1️⃣stones: kidney stones (nephrolithiasis)
2️⃣bones: bone aches and pain, osteoporosis
3️⃣groans: muscle pain,weakness, gi pain , constipation
4️⃣thrones: polyuria, polydipsia
5️⃣psychiatric overtones: depression, confsuion, memory loss
how is prathyroid hormone associated with calcium
parathyroid hormone produced by parathyroid gland to help balace ca levels in body by:
1) kidney reabsorption of ca,
2) intestine absorption of ca,
3) stimulate osteoclasts inc ca release frome bome
what happens in secondary hyper parathyroidism
caused by low vit D and chronic renal failure so low calcium would cause hyperplasia of the 4 parathyroid glands to release more PTH
tertiary hyperparathyroidism is caused by
prolonged secondary parathyroidism more hyperplasia so more calcium PTH lvl exceeds baseline so all 3 componets responsible for calcium absorption increase
what are causes of hypothyroidism
head and neck injuries
parathyroidectomy
symptoms of hypoparathyroidism
CATS go numb
convulsions
arrythmias
tetany (chovostek sign) / trousseau sign
spasms and stridor
go numb
how do u diagnose hypoparathyroisism in ecg
long QT
tx of acute severe hypercalcemia
loop diuretics
calcitonin
what is multiple endocrine neoplasia
autosomal dominant , in which several endocrine glands produce tumors either beingn or malignant they caused by gene mutations
how are MEN inherited
autososmal dominant
