hypOthyroid Flashcards

1
Q

hashimotos thyroiditis

A

chronic autoimmune thyroiditis
- assoc with hypothyroidism although may be a transient thyroxicosis in acute phase

10x in women

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2
Q

features of hashimotos thyroiditis

A
  • general hypothyroidism sx
  • goitre; firm, non-tender

anti-thyroid peroxidase (anti-TPO)
+ anti-thyroglobuline (anti-Tg)

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3
Q

general symtpoms of hypOthyroidism

A

weight gain
lethargy
cold intolerance

skin - dry, cold, coarse scalp hair

constipation, menorrhagia

neuro
- decreased deep tendon reflexes
- carpal tunnel syndrome

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4
Q

conditions assoc with Hashimotos

A

other autoimmune
- coeliac
- type 1 DM
- vitiligo

MALT lymphoma !!

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5
Q

causes of hypothyroidism

A

hashimotos
subacute thyroiditis (de Quervain’s)

iodine deficiency
post-thyroidectomy/radioiodine tx

drugs
- lithium
- amiodarone
- carbimazole (over tx)

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6
Q

side effects of levothyroxine therapy

A
  • hyperthyroidism - over tx
  • worsening angina
  • atrial fibrillation
  • reduced bone mineral density !!
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7
Q

levothyroxine drug interactions

A

iron
calcium carbonate

–> absorption of levo is reduced, give at least 4hrs apart

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8
Q

which patients should be started on a lower dose of levothyroxine

A

patients with cardiac disease
>50s
severe hypothyroidism

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9
Q

when changing thyroxine dose, when should TFTs next be checked

A

8-12wks later

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10
Q

what happens when women on thyroxine becomes pregnant

A

increased dose (25-50mcg)
(due to increased demands of pregnancy)

  • monitor carefully, aim for low-normal
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11
Q

De Quervains thyroiditis

A

subacute thyroiditis
- occurs following viral infection

typically presents with hypERthyroidism
- initial brief hyper- phase followed by longer hypo- phase

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12
Q

disease course of subacute thyroiditis (deQuervains)

A

phase 1 (lasts 3-6 weeks): hyperthyroidism, painful goitre, raised ESR

phase 2 (1-3 weeks): euthyroid

phase 3 (weeks - months): hypothyroidism

phase 4: thyroid structure and function goes back to normal

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13
Q

Subacute (De Quervain’s) thyroiditis investigations

A

thyroid scintigraphy = globally reduced uptake of iodine-131

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14
Q

Subacute (De Quervain’s) thyroiditis management

A

usually self limiting
- thyroid pain - NSAIDS/aspirin

severe cases (if hypothyroidism develops) -> steroids

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15
Q

subclinical hypothyroidism

A

TSH raised but T3/4 normal

significance;
- risk of progressing to over hypothyroidism (higher in men)
- risk increased if thyroid autoantibodies

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16
Q

management of Subclinical hypothyroidism

A

TSH >10 (+ T3/4 normal)
- offer levothyroxine on 2 separate occasions 3 months apart

TSH 5.5-10
- <65, symptomatic + levels 5.5-10 on 2 occasions 3 months apart –> 6 month trial of levo
- old -> watch+wait
- asymmptomatic -> observe, repeat TFT in 6mth

17
Q

postpartum thyroiditis phases

A
  1. thyrotoxicosis
  2. hypothyroidism
  3. normal thyroid function

(high recerrence rate in future pregs)
- anti-TPO antibodies found in 90%

18
Q

management of postpartum thyroiditis

A

thyrotoxic phase
- propranolol - for sx control
- NO anti-thyroid drugs

hypothyroid phase
- thyroxine

19
Q

sick euthyroid syndrome

A

TSH = low
free T4 = low

common in hospital inpatients
- changes are reversible upon recovery, no tx

20
Q

TFT finding in someone with poor compliance with thyroxine

A

TSH = high
free T4 = normal

TSH lags + refelcts longer term low thyroxine levels

21
Q

what drugs can cause hypothyroidism

A

lithium
amiodarone

(amiodarone can cause both hypo + hyperthyroidism)