Thyroid & Adrenals Flashcards
Why is measurement of T3 or T4 alone not recommended as an initial screen?
will miss subclinical hypothyroidism
order if free or total TSH is abnormal/low
TSH measurement alone can be misleading in which conditions?
- recent tx of thyrotoxicosis
- pituitary disease
- non-thyroidal illness
In these cases testing of free thyroid hormones is recommended in addition to the TSH assay.
Tests enabling measurement of antithyroid peroxidase autoantibodies (anti-TPO, previously referred to as thyroid antimicrosomal antibodies) are often valuable when trying to determine the cause of a thyroid disturbance.
common causes of low TSH, raised free T3 or free T4?
primary hyperthyroidism:
- Graves ds
- multinodular goitre
- toxic nodule
In these cases TSH should be undetectable and thyroid tissue should not be tender.
Clinical criteria can usually separate the three common causes of primary hyperthyroidism, however, there is no definitive test for Graves’ disease.
Tenderness over the thyroid gland and a raised erythrocyte sedimentation rate suggests subacute (postviral or De Quervain’s) thyroiditis, but can also indicate silent thyroiditis.
common causes of low TSH, normal free T3 or T4?
- subclinical hyperthyroidism
- thyroxine ingestion
common causes of raised TSH, low free T3 or T4? (primary hypothyroidism)
- chronic autoimmune thyroiditis
- post radioiodine
- post thyroidectomy
what is thyrotoxicosis
The state produced by excessive quantities of endogenous or exogenous thyroid hormone.
[thyro- + G. toxikon, poison, + -osis, condition]
Botanical tx for hyperthyroidism: what are the 4 L’s?
Lycopus
Leonurus (Traditionally used for tachycardia, arrhythmias, irritability, nervousness)
Lemon Balm (Melissa off.)
Lithospermum
Graves ds accounts for what % of hyperthyroidism?
60-80%
Clinical features of Graves?
hyperthyroidism with any of:
- ophthalmopathy
- dermopathy
- diffuse goitre
what do we know about selenium supplementation in the tx of Graves?
In patients with Graves disease, 100mcg bid of selenium may improve quality of life and ophthalmopathy, particularly if there is an underlying (if only marginal) selenium deficiency. These effects are seen within 6 months and can persist even after treatment is withdrawn. Consider recommending Brazil nuts (or other food sources).
what do we know about L-carnitine supplementation in the tx of Graves?
L-carnitine at 2g (patients generally did as well on 2g as 4g) daily may help prevent and reverse some symptoms of thyrotoxicosis with effects starting after 1-2 weeks.
what is subacute thyroiditis
Already-created thyroid hormone leaks from an inflamed gland
May or may not be painful, depending on the etiology
what is the clinical course of subacute thyroiditis?
hyperthyroid phase 1-6 mos
hypothyroid phase 2-8 mos
recovery
what is a thyroid storm?
- infection, trauma, or surgery precipitates uncontrolled hyperthyroidism in a hyperthyroid patient
- acute exacerbation of thyrotoxicosis:
hyperthermia, tachycardia, arrhythmia, pulmonary edema, vomiting, diarrhea, vascular collapse, hepatic failure, confusion, delirium, coma - 50% mortality
- medical emergency – send to ER in an ambulance
pharmacological tx of choice for hypothyroidism?
L-T4 alone
Average dose: 1.6 μg/kg/d in adults
Recommendation: start lower (as low as 12.5 μg/d) in elderly and those with CAD
Adjust dose every 4-6wks
Goal: normalize TSH
Pregnancy: Immediately following positive pregnancy test: incr. dose by 2 tablets per week – requirements should return to pre-pregnancy postpartum
Remember that in patients receiving thyroid hormone replacement, changes in TSH lag behind thyroid hormone levels.
Generally takes 6 weeks to attain new steady state after dosage adjustment. Full effect may not be reflected in TSH until after 8 wks.
