Quality Corner – Thyroid Storm and Aortoiliac Occlusive Disease
Authors: Cassandra Mackey, MD (EM Resident Physician, UT Southwestern Medical Center / Parkland Memorial Hospital) and Christine Kulstad, MD (EM Attending Physician, UT Southwestern Medical Center / Parkland Memorial Hospital) // Edited by: Alex Koyfman, MD (@EMHighAK) and Brit Long, MD (@long_brit)
Welcome to Quality Corner, an emDocs series evaluating tough cases and potential areas for improvement. The cases described below are based on ED bouncebacks, with all identifying details removed, and are limited to what was documented in the medical record.
Case 1 – Another case of the flu?
A 33-year-old male came to the ED this winter with symptoms that started several hours ago. He reported fevers, myalgias, cough, sore throat, and headache. He currently resides in a homeless shelter. On exam, he has an oral temp of 39.2 °C, a heart rate of 120, BP of 143/86, and O2 sat of 99% on room air. He has no meningismus, clear lungs bilaterally, no abdominal tenderness, and no rash. A CBC, BMP, and CXR are ordered. He is given 600 mg of ibuprofen and a total of 3L of crystalloid IVF. Aside from a WBC count of 13, his evaluation is normal. His heart rate (96) and temperature normalize after treatment. Influenza is suspected, although the PCR test is negative, and he is discharged with Tamiflu. Seems reasonable for the middle of flu season, right?
Seven hours later the patient returned to the ED, not feeling well. His vital signs were HR 118, BP 157/78, Temp 39.3 °C (102.7 °F), RR 20, and SpO2 99 %. Since he was a bounceback patient, a more thorough history was taken. Additional symptoms at this time include one week of restlessness and LE edema, as well as 2 days of nausea and diarrhea. He now reported that he had been diagnosed with a thyroid problem 3 months ago, but ran out of his medication 2 months ago. Further review of the EMR reveals that 3 months ago he was diagnosed with hyperthyroidism after a self-reported unintentional 125 lb weight loss. He had been started on metoprolol and methimazole, but was lost to follow-up.
Additional blood tests on the second visit show a TSH of <0.01, free T4 of >7.8, WBC of 13, hemoglobin of 10, and elevated BNP (NT-proBNP 2,407). Treatment was initiated with hydrocortisone, propranolol, and methimazole, and he was admitted to the MICU with an endocrine consult. This was a really difficult case with a patient who did not provide his entire past medical history on the first visit. The provider may have suffered from premature closure, as the initial symptoms suggested the flu in the middle of flu season. Premature closure is a common cognitive bias, similar to anchoring, where a diagnosis is decided early in the evaluation of a patient and additional diagnoses or testing are therefore not considered. When you’ve seen 30 patients with the flu this week, it’s difficult to widen your differential. Nothing in the documented HPI or course during the 1st ED visit refutes that diagnosis (except the negative PCR), but additional information – PMH, additional symptoms of restlessness, diarrhea, etc. – was not sought out. This is an extremely common error, one which we all would be likely to make in the same situation. Awareness of its common occurrence, plus taking time during a shift to think about each patient prior to disposition, can ameliorate this cognitive bias.
Discussion – Thyroid Storm
Let’s discuss thyroid storm – much less common than cognitive biases. It is a potentially deadly condition, with traditional mortality reported at 10-30%.1 Diagnosis can be tricky; consider using the Burch Wartofsky score,2 which is helpful if high. Additionally, looking for common precipitants is recommended, the most common of which is medication noncompliance. Other common precipitants of thyroid storm are infection, post-partum state, burns, or trauma.1 Less obviously, medications like iodinated contrast, amiodarone, lithium, aspirin, and pseudoephedrine can trigger it.3
Treatment is worth reviewing, since it consists of multiple steps that should be performed in a particular order. First step is aimed at decreasing the effects adrenergic stimulation with a beta blocker, most commonly propranolol, which also has some activity in blocking conversion of T4 to the more active T3.1 The second step is to block new hormone synthesis with propylthiouracil (PTU) or methimazole. PTU is preferred acutely because it acts more quickly, blocks conversion of T4 to T3, and is safe in pregnancy.3 Longer term, methimazole is preferred as it has less hepatotoxicity and an easier dosing regimen. Next, wait 30-60 minutes for PTU or methimazole. If your patient is still in the ED, give iodide which will inhibit release of stored thyroid hormone.3 The last component of treatment that can be easy to forget is corticosteroids, which also inhibit the conversion of T4 to T3. They also act to prevent or treat adrenal insufficiency.3
- You have to think about endocrine emergencies to recognize them: beware of cognitive biases.
- Treatment involves 4 steps: beta blocker, PTU/methimazole, iodide, and steroids.
Case 2 – Low back pain
A 55-year-old male with no known PMH came to the ED with left lower back pain that started suddenly at 8pm while he was walking to catch the bus. He describes it as sharp and shooting, with pain radiating down both legs. While he was walking, he had tingling in both feet, which has now improved, as has his pain. He had a similar problem on the right leg a couple of months ago, but it went away after a month without treatment. He denied recent injuries, weakness, fevers or chills, saddle anesthesia, bowel or bladder changes, dysuria, hematuria, and IVDU. He had normal vital signs, and a thorough, normal motor and sensory exam were documented. His skin was noted to be warm, and DP and PT pulses were 1+ in both legs. He was given ibuprofen and a muscle relaxer, felt better, and was discharged.
Ten hours later the patient came back to the ED by ambulance with worsening pain. At this point, the patient reported that he had pain intermittently for a week, and the pain was in the left low back radiating to the hip and thigh. The pain was worse with walking. Special mention was made of his longstanding smoking history. His vital signs remained normal, but at this point he was noted to have cool feet bilaterally with decreased femoral and DP pulses bilaterally. The provider was concerned about a vascular cause of the pain, so a CTA aorta with run-off was ordered. It showed occlusion of the infra-renal aorta which extended into the bilateral common iliac arteries, with reconstitution at the iliac bifurcation bilaterally. There were no large collateral vessels to suggest a chronic process.
Discussion – Aortoiliac occlusive disease
We see a lot of musculoskeletal back pain. It’s easy to assume that low back pain, especially with what seems to be radicular symptoms, will always be musculoskeletal in origin. The first provider did a very nice screen by history and physical exam to look for more worrisome causes of pain, although mostly limited to complications of the spine/spinal cord. Always consider the aorta when dealing with back pain, and not just AAA.
During the first visit, the patient did not have a dramatically abnormal physical exam and did not require an emergent vascular study. Exertional pain in the legs suggests claudication, something that can be easy to overlook since it is rarely an emergency. Lesions in the aortoiliac arteries can present with buttock, hip, and thigh pain, which can be confused with low back pain radiating to the upper legs. A long smoking history, diabetes, and other known vascular diseases should raise your level of suspicion.4 Getting the patient up and walking or measuring the ankle-brachial index might have led the provider in the right direction.5 And if you want to really show off when you consult vascular, mention your concern for Leriche syndrome. Leriche syndrome is characterized by claudication, erectile dysfunction, and absent femoral pulses and is caused by occlusion of the aortoiliac arteries.5 When vascular surgery was consulted about this patient, he did report erectile dysfunction. Treatment of Leriche syndrome, or other occlusive disease of the peripheral arteries, is generally re-vascularization, with the urgency of the procedure dependent on the severity of symptoms.6
- Don’t forget vascular causes of low back pain.
- Severity of symptoms and ankle-brachial index guide the urgency of revascularization.
- Always do a full neuro exam, including walking patients with back pain.
References / Further Reading
- Thyroid storm – UpToDate. Available at: https://www.uptodate.com/contents/thyroid-storm.
- Burch, H. B. & Wartofsky, L. Life-threatening thyrotoxicosis. Thyroid storm. Endocrinol. Metab. Clin. North Am.22,263–277 (1993).
- Chiha, M., Samarasinghe, S. & Kabaker, A. S. Thyroid storm: an updated review. J. Intensive Care Med.30,131–140 (2015).
- Lee, W.-J., Cheng, Y.-Z. & Lin, H.-J. Leriche syndrome. Int. J. Emerg. Med.1,223 (2008).
- Frederick, M., Newman, J. & Kohlwes, J. Leriche Syndrome. J. Gen. Intern. Med.25,1102–1104 (2010).
- Rutherford, R. B. et al.Recommended standards for reports dealing with lower extremity ischemia: revised version. J. Vasc. Surg.26,517–538 (1997).