Thyrotoxicosis
Thyrotoxicosis
Updated: 01/13/2021
© Jun Wang, MD, PhD
General features
- Hypermetabolic state due to elevated circulating free T3 and T4
- Associated with hyperactivity of thyroid gland, inappropriate release of thyroid hormones due to follicular damage, etc
- Three most common causes
Diffuse hyperplasia associated with Graves disease
Terms
- Hyperthyroidism: Status of thyroid hormone overproduction, may be clinically subtle, such as apathetic hyperthyroidism
- Thyrotoxicosis: Clinical presentations caused by excess circulating thyroid hormone
- Thyroid storm: Acute life threatening exacerbation of thyrotoxicosis
- Primary hyperthyroidism
Diffuse hyperplasia (such as Graves disease )
Hyperfunctional adenoma
Iodine-induced hyperthyroidism
Neonatal hyperthyroidism associated with
maternal Graves disease
- Secondary hyperthyroidism, rare
TSH producing pituitary tumor
- Not associated with thyroid hyperfunction
Thyroiditis
Exogenous thyroxine intake
Clinical presentations
- Symptoms: Hyperactivity, nervousness, anxiety, heat intolerance, etc
- General signs: Tachycardia, arrhythmia, thyroid ocular changes, weight loss, etc
- Thyroid signs: Enlargement, thyroid bruit
Thyroid oculopathy
- Lid retraction
- Lid lag on downward gaze
- “Stare”
- Edema of lids
- Proptosis: only in Graves disease
Key laboratory findings
- Low TSH, usually first positive finding
- High thyroxin or FTI
- If normal T4 or FTI, mild or subclinical
Treatment
- Antithyroid medications
- Symptom relief (rehydration, b-blockers, saline eye drops, surgery for ophthalmopathy, etc)
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