97. Thyroid Flashcards

1
Q

Limitez le dépistage de la dysfonction thyroïdienne aux patients dont la probabilité prétest de résultats anormaux est élevée.
Nommez des examples.

A

(1) ceux qui présentent les symptômes ou les signes classiques d’une dysfonction thyroïdienne ;
(2) ceux dont les signes ou les symptômes sont atypiques, mais qui sont à plus grand risque d’avoir cette maladie
* les personnes âgées
* les femmes en période postpartum
* les patients ayant des ATCD de fibrillation auriculaire
* les patients atteints d’une endocrinopathie

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2
Q

Chez le patient dont la dysfonction thyroïdienne est bien établie, ne vérifiez pas trop souvent les taux de thyréostimuline (TSH) ; faites-le plutôt à des moments appropriés, par exemple quand ?

A
  • après avoir ajusté la posologie médicamenteuse ;
  • lors du suivi des patients ayant une forme légère de thyroïdopathie ou avant de commencer le traitement ;
  • périodiquement chez les patients traités, mais dont l’état est stable.
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3
Q

Lorsque vous examinez la glande thyroïde, utilisez la technique appropriée, c-à-d comment ?

A

(c.-à-d. placez-vous derrière le patient et demandez-lui d’avaler), particulièrement pour trouver des nodules (lesquels peuvent nécessiter une investigation plus poussée).

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4
Q

Name Risk Factors for Thyroid Disease (6)

A
  • Women >45yo
  • Postpartum. No clear impact (benefit or harm) for universal screening in pregnancy
  • Radiation
  • Drug-induced (lithium, amiodarone)
  • Autoimmune disease (eg. DM1)
  • Strong family history of thyroid disease
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5
Q

Describe effect of lithium on thyroid (3)

A
  • can cause goiter
  • hypothyroidism (more common)
  • hyperthyroidism
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6
Q

Describe effect on thyroid : Interferon alfa-2b (2)

A

may cause hypothyroidism or hyperthyroidism

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7
Q

Name sx : Hypothyroidism (8)

A
  • Mood: Depression
  • Memory
  • Motor: Fatigue/Lethargy
  • Mass: Weight gain
  • Metabolism: Cold intolerance
  • Menstrual irregularities
  • Constipation
  • Dry skin
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8
Q

Name sx : Hyperthyroidism (7)

A
  • Palpitations/ tachycardia/ atrial fibrillation
  • Widened pulse pressure
  • Nervousness and tremor
  • Heat intolerance
  • Weight loss
  • Muscular weakness
  • Usually goiter is present
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9
Q

What to do if TSH high (> 4-5 mU/L) (2)

A

Possible Primary Hypothyroidism
* FT4 to determine degree of hypothyroidism
* Anti-TPO Ab once

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10
Q

What to do if TSH low (<0.2mU/L)

A

Possible Primary Hyperthyroidism
* Free T4 and T3 to determine degree of hyperthyroidism
* If no obvious cause (eg. Graves - new ophthalmopathy, goiter)
(1) Thyrotropin receptor antibodies (TRAb)
(2) Radioactive iodine uptake (contraindicated in pregnant/breastfeeding)
(3) Ultrasound with thyroidal blood flow

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11
Q

If abnormal thyroid size, nodules, what to do ?

A
  • Thyroid ultrasound
  • FNA for nodules >1cm or 5mm and suspicious features (r/o cancer)
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12
Q

Name DDX primary hypoT4 (7)

A
  • Chronic autoimmune thyroiditis
  • Iatrogenic
  • Iodine deficiency/excess
  • Drugs
  • Infiltrative diseases
  • Transient hypothyroidism
  • Congenital thyroid disease
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13
Q

Name iatrogenic causes of hypoT4 (4)

A
  • thyroidectomy
  • radioiodine therapy
  • external radiation
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14
Q

Name drugs that cause hypoT4 (7)

A
  • thionamides
  • lithium
  • amiodarone
  • interferon-alfa
  • interleukin-2
  • perchlorate
  • tyrosine kinase inhibitors
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15
Q

Name Infiltrative diseases that cause hypoT4

A
  • thyroïdite fibreuse
  • hémochromatose
  • sarcoïdose
    *
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16
Q

Name : Transient hypothyroidism (4)

A
  • Thyroïdite (lymphocytaire silencieuse, granulomateuse subaiguë, post-partum)
  • Thyroïdectomie subtotale
  • Thérapie à l’iode radioactif pour Graves
  • Arrêt des doses suppressives d’hormones thyroïdiennes chez les patients euthyroïdiens
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17
Q

Name central hypoT4 causes (2)

A
  • TSH deficiency
  • TRH deficiency
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18
Q

Name types of HypoT4 (3)

A
  • Primary
  • Central
  • Résistance généralisée aux hormones thyroïdiennes
19
Q

Name ddx avec hyperT4 : Normal/high radioiodine uptake (4)

A
  • Autoimmune
  • Tissu thyroïdien autonome
  • TSH-mediated
  • Human chorionic gonadotropin
20
Q

Name autoimmune hyperT4 ddx (2)

A
  • Graves’ disease
  • Hashitoxicosis
21
Q

Name Autonomous thyroid tissue
hyperT4 ddx (2)

A
  • Toxic adenoma
  • Toxic multinodular goiter
22
Q

Name Human chorionic gonadotropin
hyperT4 ddx (2)

A
  • Hyperemesis gravidarum
  • Trophoblastic
23
Q

Name TSH-mediated
hyperT4 ddx (1)

A

Pituitary adenoma

24
Q

Name Thyroiditis
hyperT4 ddx (5)

A
  • Subacute granulomatous (de Quervain’s) thyroiditis
  • Painless thyroiditis (silent, lymphocytic, postpartum)
  • Amiodarone
  • Radiation thyroiditis
  • Palpation thyroiditis
25
Name ddx avec hyperT4 : Near absent radioiodine uptake (3)
* Thyroiditis * Exogenous thyroid hormone intake (excessive replacement therapy) * Ectopic hyperthyroidism
26
Name Ectopic hyperthyroidism hyperT4 ddx (2)
* Struma ovarii * Metastatic follicular thyroid cancer
27
Name causes : Subclinical hypothyroidism (5)
* possible CAD * heart failure * stroke * lipids * infertility
28
Describe tx : Subclinical hypothyroidism (2)
* Consider treatment if **TSH≥20mU/L**, symptomatic, or risk (elevated Anti-TPO Ab, Goiter, strong family history of autoimmune, pregnancy) * Consider treatment in infertility
29
Name risks : Subclinical hyperthyroidism
* atrial fibrillation/flutter * heart failure * lower Bone Mineral Density
30
Desribe tx : Subclinical hyperthyroidism
Consider treatment if **TSH <0.1 mIU/L** and * Symptomatic (palpitations, tremor, nervousness) * >65yo * Comorbidities such as heart disease or osteoporosis * Postmenopausal (<65yo) and not taking estrogen/bisphosphonates
31
Describe tx : Subacute granulomatous thyroiditis (viral infection, painful thyroid) (1)
NSAIDs
32
Treatment of Hypothyroidism (5)
* Levothyroxine treatment of choice, start 12.5-50mcg/day * Target TSH euthyroid range (except in secondary hypothyroidism, where target FT4) * No evidence for levothyroxine in euthyroid (except in thyroid cancer target undetectable TSH to reduce recurrence by 40%) * Avoid TSH <0.1mIU/L * Consider higher serum TSH target in elderly and hospitalized (eg. 8)
33
# [](http://) Describe ris TSH < 0.1mlU/L
* thyrotoxicosis * A-fib * osteoporosis
34
Describe follow-up tx hypoT4 (4)
* Repeat TSH q3-4 months until stable, then yearly * If dose higher than expected, evaluate for GI disorder (H pylori gastritis, atrophic gastritis, celiac) * Follow serum TSH when started on medications, change in body weight, aging, pregnancy * Poor adherence, weekly levothyroxine should be considered
35
Describe tx : Myxedema coma (7)
* Altered mental status * hypoventilation * hypothermia * hypotension * bradycardia * hypoNa * hypoglycemia
36
Describe tx : Myxedema coma (4)
* **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)
37
What to do if elevated TSH vs low TSH ?
* Elevated TSH, rule out pituitary gland tumour * Low TSH, consider radioiodine uptake scan
38
Describe tx : Graves (3)
* Thionamides (Methimazole - MMI or Propylthiouracil - PTU) * Beta-blockers (for symptom control) : Atenolol 25-50mg daily (up to 200mg) until goal HR<90 * Ophthalmopathy: Steroids, radiation, surgical decompression
39
Describe tx : Thyroiditis (3)
* NSAIDs * Steroids * Beta-blockers for symptomatic treatment
40
Describe tx : Toxic adenoma/multinodular goiter (2)
* First-line: Radioiodine or surgery. May consider thionamide initially for short-term * Beta-blockers for symptomatic treatment
41
Name sx : Thyroid storm (6)
* Hyperthermia * Tachycardia * N/V/D * Dehydration * Delirium * Coma
42
Name causes : Thyroid storm (3)
* Trauma * Surgery * Radioactive Iodine
43
Describe tx : Thyroid storm (5)
* B-Blockers (Propranolol 60-80mg q4-6h) * PTU 200mg PO q4h * Iodine solution (delayed 1h after PTU) * Iodinated radiocontrast * High-dose IV hydrocortisone 100mg IV q8h
44
# escr