Another home-made infographic for today’s blog… this time a review of when and how to treat severe hypo & hyperthyroidism!
If there is one thing you take away from today's pearl, let it be this:
Both thyroid storm and myxedema coma are clinical diagnoses; they cannot be diagnosed definitively based on lab results. THERE IS NO CUT-OFF VALUE OF FREE T3 or FREE T4 to indicate when you should treat!! Decision to treat should be made based on severity of symptoms.
For thyrotoxicosis there is a scoring system, although not perfect, to help you make this distinction between early thyrotoxicosis and potentially life threatening thyroid storm. For myxedema coma, you may have to make this decision based on the pt's mental function & hemodynamic stability.
Other pearls:
- Thyroid storm and myxedema coma are the most severe manifestations of hyperthyroidism and hypothyroidism. Both typically present together with another medical emergency (a precipitant), most commonly sepsis.
- Hyperthyroidism is simply the state of elevated serum thyroid hormones. Thyrotoxicosis is the clinical syndrome of symptoms resulting from the effects of elevated thyroid hormones. one can be hyperthyroid but not thyrotoxic. Everyone who is thyrotoxic is hyperthyroid.
-Why do we give so many meds for thyroid storm?? Its actions, particularly on the heart, are immediately life threatening. So we attempt to stop the involved hormones in several diff ways:
1. Beta blockers are given to block the peripheral affects of T3
2. Thionamides inhibit thyroid hormone production by inhibition of thyroid peroxidase. PTU is traditionally preferred because it also has some action on peripherally preventing conversion of T4 to T3 by inhibiting 5'-deiodinase. **These meds MUST be given before Iodine so that iodine isn’t incorporated/more hormone isn’t synthesized
3. Iodine decreases the release of thyroid hormone from the thyroid gland
4. Steroids block peripheral conversion of T4 to active T3, and also helps in case of adrenal insufficiency
5. Last ditch: Apheresis can be used in critically ill pts to remove excess thyroid hormone from the serum
