Hey #MedTwitter,

An asymptomatic patient came to the outpatient clinic because of low TSH, high fT4/T3, and positive TRAb

Final diagnosis: Biotin supplement use🤔

Follow the 🧵

#Endotip #MedEd
Biotin supplements are commonly used and do not change thyroid function.

On the other hand, biotin often causes lab assay interference mimicking Graves' disease:

⬇️ TSH

⬆️ fT4 and T3

⬆️ TRAb
TRAb is a marker of Graves' disease, the most common cause of thyrotoxicosis/hyperthyroidism, and has a high accuracy :
- Sensitivity: ~ 97%
- Specificity: ~ 99%

📢Beware that despite high reliability, TRAb result can be falsely elevated in the setting of biotin use
How to deal with it?

This biotin effect lasts for only a few hours.

📢Recommend your patients who will have thyroid function assessment not to take biotin for 2 days!

👊👊
Want to know more?

nejm.org/doi/full/10.10…

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More from @mendesthiagob

22 May
Have you ever heard that nocturnal hypoglycemia causes rebound hyperglycemia in the morning?

This is also known as the Somogyi effect - published in 1938.

Did you know this concept has been contested in the last decades?

Follow the 🧵

#MedEd #diabetes #MedTwitter
Somogyi has claimed that hypoglycemia response (increase in glucagon, GH, cortisol, and) could overcompensate leading to hyperglycemia.

This is not true for most hormones' feedback. Let's use the thyroid to make a parallel:
When the thyroid loses function, TSH gets ⬆️. Can this high TSH overcompensate loss of thyroid function and cause hyperthyroidism? No!

What about glucose?
Read 8 tweets
20 May
I was working when @Rafameed texted me "watch today's VMR when possible". As soon as I got home I did it.

What a beautiful discussion @rabihmgeha, @Sharminzi, @KirtanPatolia, and @sukritibanthiya !

Just a short pearl🧵
> 2/3 of pts with adrenal insufficiency have other autoimmune condition(s).

10% of patients with adrenal insufficiency have pernicious anemia.

Bottom line: if you see a patient with autoimmune disease and hyponatremia and hyperpigmentation, check morning cortisol.
Read 4 tweets

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