97. Thyroid Flashcards
In patients with established thyroid disease, do not check thyroid-stimulating hormone levels too often, but rather test at the appropriate times, such as when ? (3)
- after changing medical doses.
- when following patients with mild disease before initiating treatment.
- periodically in stable patients receiving treatment.
When examining the thyroid gland, use proper technique. Explain how.
- from behind the patient, ask the patient to swallow)
- especially to find nodules (which may require further investigation).
Name Risk Factors for Thyroid Disease (6)
- 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
Describe effect of lithium on thyroid (3)
- can cause goiter
- hypothyroidism (more common)
- hyperthyroidism
Describe effect on thyroid : Interferon alfa-2b (2)
may cause hypothyroidism or hyperthyroidism
Name sx : Hypothyroidism (8)
- Mood: Depression
- Memory
- Motor: Fatigue/Lethargy
- Mass: Weight gain
- Metabolism: Cold intolerance
- Menstrual irregularities
- Constipation
- Dry skin
Name sx : Hyperthyroidism (7)
- Palpitations/ tachycardia/ atrial fibrillation
- Widened pulse pressure
- Nervousness and tremor
- Heat intolerance
- Weight loss
- Muscular weakness
- Usually goiter is present
What to do if TSH high (> 4-5 mU/L) (2)
Possible Primary Hypothyroidism
* FT4 to determine degree of hypothyroidism
* Anti-TPO Ab once
What to do if TSH low (<0.2mU/L)
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
If abnormal thyroid size, nodules, what to do ?
- Thyroid ultrasound
- FNA for nodules >1cm or 5mm and suspicious features (r/o cancer)
Name DDX primary hypoT4 (7)
- Chronic autoimmune thyroiditis
- Iatrogenic
- Iodine deficiency/excess
- Drugs
- Infiltrative diseases
- Transient hypothyroidism
- Congenital thyroid disease
Name iatrogenic causes of hypoT4 (4)
- thyroidectomy
- radioiodine therapy
- external radiation
Name drugs that cause hypoT4 (7)
- thionamides
- lithium
- amiodarone
- interferon-alfa
- interleukin-2
- perchlorate
- tyrosine kinase inhibitors
Name Infiltrative diseases that cause hypoT4
- thyroïdite fibreuse
- hémochromatose
- sarcoïdose
*
Name : Transient hypothyroidism (4)
- 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
Name central hypoT4 causes (2)
- TSH deficiency
- TRH deficiency
Name types of HypoT4 (3)
- Primary
- Central
- Résistance généralisée aux hormones thyroïdiennes