thyroid storm now hypothyroid

[dogwoodhill]

I recently had thyroid storm which came on acutely.  I never had thyroid problems in the past (TSH 0.4) several months earlier which is within our ref range. The cause of the storm is still unknown. My TSH was 0.001 during the storm.  I was started on methimazole 30mg a day and 3 weeks later TSH was 0.002 free T4 0.44 (ref range starts at 0.89 on low end).  Methimazole lowered to 10 mg a day because of the Ft4 result.  Today (4 weeks later) TSH is 50 and FT4 is 0.45  Have you ever seen this???  I don't have antibodies so my endo doesn't think it's Graves, I don't have a pit tumor, I didn't have a lot of neck pain so doubt it was thyroiditis.  Help!  am I doomed to swing between severe hyper and hypo? I'm off all meds as of today and will recheck FT4 in 2 weeks.

[Mark Lupo, M.D.]

Thanks for the additional info.  As you know, storm is rare and frequently over-used by patients to describe what is simply thyrotoxicosis w/o cardiac decompensation.  You had a real storm with siginficant hyperthryodism.  The evaluation at this point is most c/w thyroiditis though somewhat atypical and more severe than usual.  

The I-123 scan will show increased uptake in the hypo phase of recovery for thyroiditis -- this is often a pitfall in diagnosis - so beware of this.  It is key to know the TSH at the time of the uptake in order to interpret the test in the proper clinical setting.  So, the I-123 is most useful if the hyperthyroidism returns....

[dogwoodhill]

It was storm- heart failure and really MODS/MOF.  In hospital 11 days.  I'm actually an ER doctor but I know very little about the endo system (typical for most ER docs I think).  no uptake scan was done.  TSI was normal.  My T3 in hospital was >20 so it couldn't be measured.  Going to do uptake scan a couple of weeks per endo.  Thanks for your input.

[Mark Lupo, M.D.]

This was likely a subacute transient thyroiditis (without pain) with hyperthyroidism.  It was not a true storm unless you were in ICU with severe unstable cardiac complications.  It was likely a sever hyper episode.  Now you are going through the hypo phase of thyroiditis and the methimazole had no impact whatsoever on your thyroid levels coming down, but is likely hindering the recovery.  Being off meds makes since with a close follow-up.  85% of patients with this history have a full recovery.  In addition about 20% have a recurrence of thyroiditis.  Did you have an I-123 uptake during the hyper phase?  If so, that would have differentiated between graves and thyroiditis.  Also the TSI antibody can help -- but my guess is thyroiditis.