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Thyroid > Benign Conditions > Flashcards

Benign Conditions Flashcards

1
Q

What is hyperthyroidism?

How do you classify hyperthyroidism?

A

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

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2
Q

Hyperthyroidism signs and symptoms?

A

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

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3
Q

Two anti-thyroid drugs?

A

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,

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4
Q

Grave’s Disease? Etiology?

A

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

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5
Q

Symptoms?

A

-exophthalamos (due to inflammatory cell infiltration into extraocular muscles, connective tissue) -lid lag -tibial myxedema -diffuse goitre

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6
Q

What kind of imaging would indicate that you have Grave’s?

What would be biochemical indicators of Grave’s?

A

radioactive 123 iodine uptake- symmetrically enlarged gland with increased 24 hour RAIU measurements

Elevated T3, with decreased TSH (due to negative feedback suppression)

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7
Q

Treatment for Grave’s disease?

A

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

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8
Q

What are the surgical indications for Grave’s disease?

A
  • 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)
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9
Q

What is the definition of near total thyroidectomy?

A

Leaving <1 g of thyroid near RLN to maintain euthyroidism

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10
Q

Toxic nodular goiter is also known as : _______

What is the etiology of toxic nodular goitre?

A

Plummer’s disease

autonomous function of goitre

Etiology: focal and/or diffuse hyperplasia of thyroid follicular cells, not regulated by TSH

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11
Q

How to investigate toxic nodular goitre?

A

By toxic- it means functioning (producing T3/T4)

So you should start with TSH measurements

RAIU scan- look for pattern of uptake

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12
Q

What is the choice of surgery for toxic adenoma?

Toxic multinodular goitre?

A

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

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13
Q

Jod Basedow effect?

A

when the iodine supply increases, autonomous areas produce thyroid hormone independent of normal regulatory mechanisms

(Describes how autonomous nodules behave in iodine excess)

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14
Q

Wolff-Chaikoff effect?

A

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

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15
Q

Solitary toxic adenoma- treatment

A

First line: Surgery (lobectomy)

Second line: distant choice 131-RAI

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16
Q

Differential diagnosis of primary hypothyroidism?

A

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

17
Q

Cause of secondary hypothyroidism?

A

steroids- suppresses pituitary-thyroid axis; acts in periphery to inhibit T3 conversion

18
Q

Hashimoto’s thyroiditis-

epidemiology?

etiology?

diagnosis?

A

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

19
Q

Post partum thyroiditis?

A

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

20
Q

How to treat post partum thyroiditis?

A

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

21
Q

Acute suppurative thyroiditis

Symptoms?

A
  • 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

22
Q

Acute suppurative thyroiditis?

Etiology?

Is this a hypo, eu or hyperthyroid condition?

A

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

23
Q

How to work up acute suppurative thyroiditis?

A

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

24
Q

How can thyroid gland become infected? (Routes of spread)

A
  • 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

25
Q

Treatment of acute suppurative thyroiditis?

A

antibiotics (penicillin or ampicillin)

FNA can be used to speciate bug

26
Q

Subacute thyroiditis?

Etiology?

Symptoms?

A

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

27
Q

Treatment for subacute thyroiditis?

A

may use beta blockers, anti-thyroid meds not useful, NSAIDs for pain control

usually self limiting disease

28
Q

Reidel Thyroiditis?

Etiology

A

invasive fibrous thyroiditis or Reidel struma

replacement of all or part of parenchyma by fibrous tissue, which also invades adjacent tissues

chronic inflammatory process

29
Q

Reidel thyroiditis

Hypo, eu or hyperthyroid?

How to work this up?

A

-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

30
Q

Treatment of Reidel Thyroiditis?

A

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

Thyroid (10 decks)

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