Benign Conditions Flashcards
What is hyperthyroidism?
How do you classify hyperthyroidism?
1) Primary hyperthyroidism:
Common causes: Grave’s (70%), toxic nodular goitre, toxic thyroid adenoma
unusual causes: molar pregnancy with increased release of hCG (related to TSH-beta subunit), exogenous thyroid ingestion, thyroid malignancy with overproduction thyroid hormone
2) Secondary hyperthyroidism
pituitary problem
3) Tertiary hyperthyroidism
hypothalamus problem
Hyperthyroidism signs and symptoms?
Organize by systems: (Think of sympathetic overdrive)
HEENT: Eyes- exophthalamos/orbitopathy
CNS: nervousness and insomnia
Skin: heat intolerance, sweating, flushing, tremor
GI: increased BM, diarrhea
Cardiac: palpitations, tremors, A-fib, tachycardia
Two anti-thyroid drugs?
Propylthiouracil: inhibits organification of iodide and coupling of monoiodotyrosine and di-iodotyrosine
inhibits peripheral conversion of T4 to T3, making it useful for treatment, use in first trimester pregnancy
1% risk of agranulocytosis
Methimazole: member of thionamide family, inhibits coupling of mono/diiodotyrosine to make T4/T3, inhibits peripheral conversion
associated with congenital aplasia,
Grave’s Disease? Etiology?
Autoimmune disorder with genetic predisposition -most common cause of hyperthyroidism presence of TSH-R auto antibodies -bind to TSH receptor on follicular cells and stimulate thyroid hormone release
Symptoms?
-exophthalamos (due to inflammatory cell infiltration into extraocular muscles, connective tissue) -lid lag -tibial myxedema -diffuse goitre
What kind of imaging would indicate that you have Grave’s?
What would be biochemical indicators of Grave’s?
radioactive 123 iodine uptake- symmetrically enlarged gland with increased 24 hour RAIU measurements
Elevated T3, with decreased TSH (due to negative feedback suppression)
Treatment for Grave’s disease?
Medical
first line therapy is thionamide and beta blockers, not permanent solution, goal is to make euthyroid for RAI or surgery
only 20-30% achieve permanent remission
Radioactive iodine
very effective, ablates in 6-18 weeks on average
may take up to six months to achieve definitive results and so anti-thyroid drugs must continue in this period
RAI can transiently worsen ophthalmopathy
Contraindcations to RAI: pregnant, lactating, suspicious nodule
Surgery
near total thyroidectomy or total thyroidectomy
What are the surgical indications for Grave’s disease?
- large goiters (>80 g)
- severe hyperthyroidism
- pregnant or wanting to become pregannt in next 6 months, breast feeding mothers
- thyroid nodules suspicious for malignancy
- concomitant hyperparathyroidism requiring surgery (you’re there anyways for the parathyroid, you can also remove thyroid)
What is the definition of near total thyroidectomy?
Leaving <1 g of thyroid near RLN to maintain euthyroidism
Toxic nodular goiter is also known as : _______
What is the etiology of toxic nodular goitre?
Plummer’s disease
autonomous function of goitre
Etiology: focal and/or diffuse hyperplasia of thyroid follicular cells, not regulated by TSH
How to investigate toxic nodular goitre?
By toxic- it means functioning (producing T3/T4)
So you should start with TSH measurements
RAIU scan- look for pattern of uptake
What is the choice of surgery for toxic adenoma?
Toxic multinodular goitre?
Toxic adenoma without evidence of nodules in contralateral lobe –> ipsilateral lobectomy
Toxic adenoma and co-existing non functioning nodule in contralateral lobe –> total thyroidectomy
Multinodular goitre –> near total or total thyroidectomy
Jod Basedow effect?
when the iodine supply increases, autonomous areas produce thyroid hormone independent of normal regulatory mechanisms
(Describes how autonomous nodules behave in iodine excess)
Wolff-Chaikoff effect?
describes normal feedback physiology
Reduction in thyroid hormones levels caused by ingestion of large amount of iodine
Wolf down iodine- more T4 created, less TSH in places where iodine replete people
Solitary toxic adenoma- treatment
First line: Surgery (lobectomy)
Second line: distant choice 131-RAI
Differential diagnosis of primary hypothyroidism?
Metabolic- dietary iodine deficiency (50-70% risk of hypothyroidism with 10 mCi of radiation)
Post-radiation
Post-surgical
Drugs: anti-thyroid drugs, amiodarone (iodine rich- suppresses thyroid, may present with exacerbation of cardiac disease), lithium (inhibits production of thyroid hormone), steroids- suppress TSH concentration
Autoimmune- Hashimoto’s thyroiditis, Reidel Struma
Cause of secondary hypothyroidism?
steroids- suppresses pituitary-thyroid axis; acts in periphery to inhibit T3 conversion
Hashimoto’s thyroiditis-
epidemiology?
etiology?
diagnosis?
Chronic thyroiditis- most common cause of goitre and hypothyroidism in USA
usually 30-60 years old, womem more commonly affected
typically present with painless diffuse goitre in young woman, with or without hypothyroidism
Diagnosis: high TSH, send for autoantibodies- TPOAb and TgAb
Post partum thyroiditis?
subacute lymphocytic thyroiditis (immune phenomenon that goes with hormonal changes in pregnancy)
self limiting usually
fluctuating course- can have abrupt onset of thyrotoxicosis, then euthyroid then hypothyroid (can be permanent or transient)
24 hour RAIU initially may be low consistent with damage on cellular level
How to treat post partum thyroiditis?
initial control of symptoms: beta blockade
Do not give anti-thyroid drugs because gland not hyperfunctioning at follicular level
can institute Synthroid during hypothyroid phase for symptomatic relief
Acute suppurative thyroiditis
Symptoms?
- bacterial infection causing suppuration (pus)
- clinical prodrome usually: viral or bacterial URTI, significant fever and malaise, radiating pain to region of ipsilateral ear
may be related to pyriform sinus fistula or other congenital abnormality
Acute suppurative thyroiditis?
Etiology?
Is this a hypo, eu or hyperthyroid condition?
Bacterial infection
Staph aureus (<30%) and Strep pyogenes/anaerobes (70%) are most common pathogens
painful but transient goitre may be evident, which often is thyroidal or perithyroidal abscess
Patient usually euthyroid and anti-thyroid antibody titres normal
How to work up acute suppurative thyroiditis?
24 hour RAIU scan: often shows decreased uptake in region of active infection
bacterial infection of thyroid may occur via hematologic spread from distant site or local infiltration from other head and neck infection
-can occur from fistulous communication from pyriform sinus
How can thyroid gland become infected? (Routes of spread)
- Hematogenous
- Lymphatic
- Direct spread from persistent pyriform sinus fistulae or thyroglossal duct cysts
- penetrating trauma to thyroid gland
- immunosuppression
**Usually thyroid gland is quite resistant to infection because of excellent blood and lymphatic supplies, high iodide content and fibrous capsule
Treatment of acute suppurative thyroiditis?
antibiotics (penicillin or ampicillin)
FNA can be used to speciate bug
Subacute thyroiditis?
Etiology?
Symptoms?
aka de Quervain thyroiditis, giant cell thyroiditis, pseudogranulomatous thyroiditis
cause not entirely known, but thought to be virally related
Prodrome consistent with viral URTI - very common
Symptoms: fever, malaise, painful goitre
Treatment for subacute thyroiditis?
may use beta blockers, anti-thyroid meds not useful, NSAIDs for pain control
usually self limiting disease
Reidel Thyroiditis?
Etiology
invasive fibrous thyroiditis or Reidel struma
replacement of all or part of parenchyma by fibrous tissue, which also invades adjacent tissues
chronic inflammatory process
Reidel thyroiditis
Hypo, eu or hyperthyroid?
How to work this up?
-euthyroid at presentation, but may eventually become hypothyroid
detectable anti-thyroid antibody titres may be present
normal ESR
24 hour RAIU scan- often normal or somewhat decreased
Treatment of Reidel Thyroiditis?
surgery is mainstay and initial treatment of choice
-chief goal is to decompress trachea by wedge excision of thyroid isthmus and make tissue diagnosis
more extensive resections not advised due to infiltrative nature of fibrotic process that obscures usual landmarks and structures
Hypothyroid patients- treated with thyroid hormone replacement as well
