A 45 year old woman with a past medical history of hyperthyroidism is brought into the emergency department by her partner. She has had urinary tract symptoms for the last 2 days, but now she looks really sick. She has been having diarrhea and crampy abdominal pain. She is having a hard time concentrating, is tremulous, and drenched in sweat. Her vital signs at triage include an irregular heart rate of 142 and a temperature of 39.5 degrees celsius. Do you have an approach to thyroid storm?
My approach to thyroid storm
The diagnosis of thyroid storm is clinical. Laboratory testing, although helpful, does not distinguish between thyrotoxicosis and thyroid storm.1 Treatment should be started immediately based on clinical findings.2 The key clinical features are: fever, altered mental status, and signs of sympathetic over-activity.
Support airway and respiration as necessary.
Manage agitation. Significant agitation can interfere with the other urgent interventions that are required. If the patient is significantly agitated, treat with a benzodiazepine.3
- Midazolam 5-10mg IV q5min as needed
Take control of the body temperature. Start cool IV fluids and external cooling as necessary.2,3
Begin fluid resuscitation. These patients will essentially all require fluids.1 Some will be in heart failure as part of their presentation, but it is high output heart failure, and even these patients will probably need fluids. The patients will also have low glycogen reserves, so adding sugar to your fluids makes sense.1
Start a beta-blocker. This will help control cardiac arrhythmias and will also make the patient more comfortable by controlling tremor. Propranolol is the agent typically used, because it inhibits the peripheral conversion of T4 to T3 and is non-cardioselective so it will also control symptoms such as agitation, fever, and psychosis.1 Esmolol is also a reasonable choice.2 The target should be a heart rate less than 90.3 Note: EMCrit suggests a target heart rate of 100, because there are some case reports of cardiovascular collapse after propranolol that might be the result of these patients requiring a rapid heart rate as a compensatory mechanism.
- Propranolol: start with 0.5-1 mg slow IV push, then titrate 1-3 mg IV q 10 min1
- Esmolol 500 mcg/kg load over 1 min, then 50-200 mcg/kg/min1
- If the patient has a significant contraindication to beta-blockers, you can use reserpine 2.5-5 mg IM q4h1
Start a thyrostatic agent (thionamide) to lower thyroid hormone levels. Propylthiouracil is the preferred agent, because it also inhibits the peripheral conversion of T4 to T3.3 Both of these agents can be given through a NG tube or rectally if needed.1
- Propylthiouracil 600-1000 mg PO (loading dose)1
- Methimazole 20-25 mg PO (loading dose). An IV version is available in Europe, but not in North America.1
Give a dose of glucocorticoid. Thyroid storm typically causes depression of the hypothalamic-pituitary axis. Glucocorticoids also inhibit the peripheral conversion of T4 to T3. 2
- Hydrocortisone 300 mg IV2
Search for the underlying cause. For hypothyroidism to progress to thyroid storm, there generally has to be a precipitating event.1,3 The most common cause is going to be infection, and as these patients are going to present hot and altered, I would routinely culture and start empiric antibiotics on any patient I am treating for thyroid storm.1 Other important causes to consider are: myocardial infarction, DKA, pregnancy, and trauma.3 Amiodarone is another potential trigger (because of the iodine) and the diagnosis might be partially masked because of the beta-blocking properties of amiodarone.
In refractory cases, or if there are absolute contraindications to the above medications, other therapeutic options are lithium, hemodialysis, charcoal hemoperfusion, and plasmapheresis.1,3
- Lithium 300mg every 8 hours3
Iodine administration is not part of the urgent management of these patients because it must be given at least 1 hour after the thyrostatic medication. These patients will all get iodine, but there is not a rush as long as you have started the other therapies, so it can be left the the admitting team.
Without treatment, thyroid storm is universally fatal. With treatment, the mortality is still as high as 20-50%.1
Salicylates should be avoided. They can make the thyrotoxicosis worse by decreasing binding to thyroid binding protein and therefore increasing levels of free T4 and T3.1
Most sources seem to advise against giving empiric antibiotics.1 However, we are generally working with limited information in the emergency department. If the patient is febrile and altered, I think antibiotics should be given up front and then sorted out later.
There are clinical criteria for thyroid storm. A score of 45 or more is highly suggestive of thyroid storm. A score of less than 25 makes thyroid storm unlikely. The grey area in between is exactly that, grey area, but could represent impending thyroid storm.2,3
Other FOAMed Resources
- McKeown NJ, Tews MC, Gossain VV, Shah SM. Hyperthyroidism. Emergency medicine clinics of North America. 23(3):669-85, viii. 2005. [pubmed]
- Chiha M, Samarasinghe S, Kabaker AS. Thyroid storm: an updated review. Journal of intensive care medicine. 30(3):131-40. 2015. [pubmed]
- Sharp CS, Wilson MP, Nordstrom K. Psychiatric Emergencies for Clinicians: The Emergency Department Management of Thyroid Storm. The Journal of emergency medicine. 51(2):155-8. 2016. [pubmed]