224. Thyroid Disorders: Hyperthyroidism and Thyroid Storm

Definitions

Hyperthyroidism: increased thyroid hormone from increased production in the thyroid.

Thyrotoxicosis: increased thyroid hormone (doesn’t have to be just from thyroid production).

Thyroid storm: extreme thyrotoxicosis. Basically Thyrotoxicosis + fever + AMS

Hyperthyroidism

Graves Disease: MCC, 85%. Usually diffuse goiter, ophthalmopathy, local dermopathy. Needs to have thyroid antibody titer ordered to confirm diagnosis.

Toxic multinodular goiter: Second MCC.

Low TSH, elevated free T4 (dont check Total T4). 95% will have low TSH/high T4. 5% will have high T3 only. T3 is the more active form and can sometimes tell severity by the level of T3. T3 is the better test to check than T4 in the acute setting (USC Rounds, 2017).

Electrolyte abnormalities: usually hyperglycemia, hypercalcemia, elevated LFTs.

Thyroid ultrasound done in outpatient setting.

Clinical features: Lethargy, weakness, diaphoresis, weight loss, heat intolerance, diplopia, dry eyes, exophthalmos, dysnpea, palpitations, chest pain, diarrhea, oligomenorrhea, irregular periods, pale skin, hair loss.

ED Initial Treatment: Likely just HR control – control with propranolol (twice daily, inhibits peripheral conversion as well) vs atenolol (only once a day treatment). Make sure elevated HR is mild, no underlying illness (infection) and needs good followup to start thionamides and outpatient workup.

Thyroid Storm

Generally patient with hx/o hyperthyroidism with high fever and altered mental status.

Burch and Wartofsky’s Diagnostic Parameters (Link): Basically looking at 6 markers and depending on severity score for each, high suspicion for thyroid storm: Fever, CNS abnormalities (delirium, psychosis, confusion/concentration, seizure/coma), GI-hepatic (nausea/vomiting, diarrhea), Tachycardia, CHF findings, Atrial Fibrillation.

Fever: generally pretty high; don’t cool these patients, treat underlying abnormality first. Cooling will cause vasoconstriction and possible worsening fever/temperature later. Tachycardia is usually out of proportion to fever.

CNS Abnormalities: can be as little as decreased concentration, though usually the hallmark is some marked confusion/psychosis. Any delirious/psychotic patient with fever/tachycardia, consider TS. Example of patient thinking their Jesus. Behavioral Health patient with either fever or elevated HR – check TSH.

CHF findings: high volume output CHF (HR too high to pump adequate blood out of heart) – can tolerate fluids, though if in severe CHF, be careful with them. Also listen for murmur or friction rub. Do not use diuretics.

Atrial Fibrillation: stick with Beta Blockers. Afib usually converts once HR decreases and TS is more controlled. Stay away from CCBs or digoxin.

Treatment

Fluids: usually greatly dehydrated. Add in dextrose if hypoglycemia. Diuretics relative contraindications (at least multiple doses given likely high output CHF).

Beta Blockade: Propranolol IV 1-2mg boluses (1mg test dose), every 10-15min or Atenolol 25-100mg qdaily. Start drip after that (max 3-5mg/hr). Esmolol 500mcg/kg IV bolus, 50-200mcg/kg/min after. HR goal 90-100. If asthma or contraindication, consider Reserpine or Guanethidine.

Inhibit hormone production with thionamides: PTU (propylothiouracil) 600-1000mg load, 200-250mg q4hr, PO/PR only. Also has peripheral conversion inhibition unlike methimazole and is safe in pregnancy, SE: agranulocytosis. Methimazole 40mg load, 25mg q4h, Also only PO/PR.

Inhibit hormone release: Wait 1 hour after thionamide: Lugol solution 8-10 drops q6-8hr, SSKI 5 drops PO q6h (Potassium Iodide – used in HIDA scan), Telepaque (IV iopanoic acid) 1g q8hr, Oragrafin (Ipodate) 0.5-3g/d PO (basically oral contrast)  or Lithium carbondate 300mg q6hr (if iodine allergy).

Inhibit Peripheral conversion: Main drug is hydrocortisone or decadron. Many prefer dexamethasome (decadron) 2-4mg q6h (doesn’t affect adrenal testing as well). Hydrocortisone 100mg IV q8hr is another option or hypotension involved.

Exogenous Thyroid Overdose: Only need to beta-block and give decadron for peripheral conversion. Hold off on thionamide/iodine since the thyroid still is functioning fine since it the medication is causing the problem.


Resources / References

Tintinalli, 6th Edition, Chapter 224: Thyroid Disorders: Hyperthyroidism and Thyroid Storm

Crashing Patient, Scott Weingart, Thyroid Disorders, Reviewed 11/4/15 (FREE)

EMRAP, June 2010, Hyperthyroidism, Stuart Swadron and Jonathan Lepresti

EBMedicine, Identifying and Treating Thyroid Storm and Myxedema Coma in the ED, 2009 (FREE)

EMCrit, Scott Weingart, Podcast 149: Thyroid Storm (FREE)

WikiEM – Thyroid Storm (FREE)

EM in 5, Thyroid Storm Video (FREE)


Clinical Cases


Board Questions

Q1.What medication do you absolutely do not NOT want to start first on someone you are suspecting thyroid storm?

A1. Iodine containing medication (needs to be given 1-2 hrs after thionamides).

Q2. Patient presents with thyroid storm and need to stop hormone production, but patient has a severe iodine allergy listed. What other medication can you give as a substitute after giving a thionamide?

A2. Lithium. Put amiodarone as one of the choices as well (amiodarone causing increased hormone levels).

Q3. Which of the following is not in the criteria for thyroid storm by Burch and Wartofsky?

A3. Free T4 / TSH level. List 3-4 others on the list of 6: Temperature, CNS, Gi, Cardiovascular, CHF, Afib.

Q4. Most common EKG finding with thyroid storm?

A4. Sinus tachycardia. List A fib, SVT, Vtach, LBBB.

Q5. Patient presents with likely thyroid storm with dyspnea, rales, pitting edema. What medication would you likely not start with on acute management?

A5. Diuretics. List saline bolus, propranolol, etc.

224. Thyroid Disorders: Hyperthyroidism and Thyroid Storm

223. Thyroid Disorders: Hypothyroidism and Myxedema Crisis

Hypothyroidism

High TSH, low free T4/T3.

No perfect thyroid test. TSH is monitoring pituitary T3. Accurate only under ideal health. Free T4 is likely better test with TSH is the new state. Hypothyroid is a clinical diagnosis. (USC Rounds, 2017)

Causes: Autoimmune (Hashimoto), Thyroiditis (subacute, silent, postpartum), ablation, Drugs (amiodarone, lithium, alpha-Interferon, interleukin-2).

Symptoms: weight gain, weakness, fatigue, vocal changes (hoarse/deep), delayed DTRs, non-pitting edema (myxedema – periorbital, nondependent areas), paresthesias, poor memory/confusion, constipation, dysfunctional uterine bleeding. 5% of carpal tunnel patients have it.

Low voltage EKG.

Hypothyroidism usually cannot produce WBC. Usually 3-4k, lymphocytic predominant. If higher around 8-10k, really consider infection.

Initial ED Management with simple hypothyroidism: Likely discharge with followup with PCP for outpatient workup/treatment.

Myxedema Coma/Crisis

Extreme presentation of hypothyroidism. High mortality, life-threatening. Misleading name: usually not myxedema apparent, rarely in coma.

90% are women in winter months. Usually elderly > 60yo.

Clinical diagnosis. Altered (some big degree of AMS), hypothermia, body habitus for hypothyroidism. Usually bradycardia, hypotension, hypothermia. Stressor involved: infection (MCC), trauma, MI/CHF, surgery, medications, etc. Usually does not have a temperature and if has a normal temperature, have high suspicion for infection. Pleural effusions can be present. Look for thyroidectomy scar in altered patient. Usually hyponatremia. CPK almost always > 500.

Treatment

Supportive care: usually dehydrated, passive warming with warming blankets, vasopressors if unresponsive to fluids. ICU admission.

Usually adrenal insufficiency involved so give hydrocortisone 100mg q8h before thyroid medication. Send random cortisol level before doing this if able.

Start with T4 over T3. Smooth/gradual rise, no high peaks and increased potential for arrhythmias/MI as T3. T3 though has advantage of quicker onset and no potential for decreased peripheral conversion (T4 to T3), though usually not recommended over T3. T4 500mcg or 200-400mcg (4mcg/kg) IV bolus, then 100mcg daily after that. Likely just stick with T4 only. If you’re going to give T3 (probably stay away from), give T3 5-20mcg IV bolus or consider giving very small bolus of T3 along with T4 if you really want to give T3 as well. Since body is converting T4 to T3, with giving a high dose of T4, the body will adjust to convert the appropriate amount to T3 so pretty safe to give high dose T4 (not T3 though). IV dose still takes around 12 hours before HR response.

Give antibiotics regardless of if theres an apparent infection initially since the myxedema coma masks many of the signs of infection.


References / Resources

Tintinalli, 7th Edition, Chapter 223: Thyroid Disorders: Hypothyroidism and Myxedema Coma

CrashingPatient.com, Scott Weingart, Thyroid Disorders, Reviewed 11/6/15 (FREE)

EBMedicine, Identifying and Treating Thyroid Storm and Myxedema Coma in the ED, 2009 (FREE)

EMRAP, Stuart Swadron / John LoPresti, Severe Hypothyroidism, 2010

WikiEM, Myxedema Coma (FREE)


Clinical Cases


Board Questions

Q1. Which type of patient is most characteristic to be in myxedema coma?

A1. Elderly woman with pneumonia in January. Incorrect answers: Dehydrated marathon runner, Male with MI that he presented 3-4 days later, Obese young female collapses and comes in unresponsive by EMS, etc.

Q2. Which drug does not cause affect the thyroid and can cause hypothyroidism?

A2. Droperidol. Incorrect answers: Lithium, Amiodarone, Phenytoin, All the above.

Q3. With a patient in myxedema coma from a MI/CHF, which medication should be given?

A3. T4. Incorrect answers: T3, Amiodarone, Beta-blocker, All the above.

Q4. Besides T4 and supportive measures, what other medication should be likely given with severe myxedema coma?

A4. Hydrocortisone. Incorrect answers: Amiodarone, Beta-Blocker, Methamazole, etc.

Q5. Whats the most common EKG finding in myxedema coma?

A5. Sinus bradycardia. Incorrect answers: Slow atrial fibrillation, bigimeny, ventricular tachycardia, second degree heart block, etc.

Q6. What lab abnormality is usually present with myxedema coma?

A6. Elevated CPK. Incorrect answers: Significant leukocytosis, hypernatremia, positive HCG, etc.

223. Thyroid Disorders: Hypothyroidism and Myxedema Crisis