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Chapter 1

IM in the ED

Rob Orman, MD and Neda Frayha, MD
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24:49

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Internist Neda Frayha sprinkles some IM in the ED - how to interpret TSH levels and why aspirin is no longer recommended for a-fib thromboprophylaxis.

 

 

Pearls:

  • A mild abnormality in the TSH can be further worked up by a PCP.

  • Only when a TSH is very high (>10) or very low (close to zero) should more urgent workup take place.  The next step is checking a free T4 and total T3.

  • For a patient with primary hypothyroidism (TSH>10, low free T4, and low total T3), levothyroxine can be started at a dose of 1.7 micrograms/kg/day (ideal body weight).  

  • Beta-blockers can be started on patients with hyperthyroidism who are symptomatic.

  • Aspirin should not be used for the treatment of non-valvular AF.  Not only does it not reduce the risk of stroke, but also it has bleeding risks equivalent to warfarin and NOACs.

 

  • Internal medicine topic #1:  Interpreting abnormal TSH results.

    • It is increasingly common for ED providers to order thyroid function testing.  Is a slight abnormality in the TSH a cause for alarm?  No.

      • It is very common for the TSH to be abnormal when a person is acutely ill.

      • Frayha does not recommend checking a TSH unless you are spcifically concerned about thyroid disease.

      • An mildly abnormal TSH drawn on an acutely ill person is best managed by a primary care provider who will typically repeat the lab in 4-12 weeks, when the patient is out of the acute illness stage.

        • Pantalone, Kevin M., and Christian Nasr. "Approach to a low TSH level: patience is a virtue." Cleve Clin J Med 77.11 (2010): 803-11.PMID: 21048053 Full Text

      • What is considered a slight versus a significant TSH abnormality?

        • A TSH < 10 is considered mildly abnormal.  Frayha does a more urgent work-up if the TSH is 10-20.

        • A TSH close to zero is worrisome for overt hyperthyroidism and should be promptly evaluated. A value between zero and the lower end of normal range may or may not be significant. Usually additional thyroid hormone studies are performed to complete the workup more fully.

      • When a TSH returns either very high or very low, what is the next step and/or test to order?  

        • Additional labs that are most helpful are a  free T4 and a total T3.

        • A patient with a markedly elevated TSH can generally wait to see the PCP to start thyroid replacement therapy, provided this follow-up can occur within a week or two and the patient is not critically ill.

      • Rules of thumb for starting thyroid replacement therapy in those with hypothyroidism:

        • For a patient with primary hypothyroidism (TSH>10, low free T4, and low total T3), start levothyroxine at a dose of 1.7 micrograms/kg/day based on ideal body weight.  For most adults, this is 100-125 micrograms daily.

        • A lower dose is initially started if the patient is elderly or has cardiovascular disease.   50 micrograms daily is reasonable in these populations.

        • Repeat labs in 4-8 weeks to ensure the dose is correct.

      • Managing hyperthyroidism can be trickier.

        • These patients usually need imaging studies (often radioactive iodine uptake studies) to sort out the cause and to guide treatment.  

        • Starting a beta-blocker in the ED can be helpful, especially if the patient is symptomatic due to tachycardia.  The beta-blocker has the additional benefit of decreasing the peripheral conversion of T4 to T3.

  • Internal medicine topic #2:  Thromboprophylaxis in patients with atrial fibrillation (AF) who have a low CHADS2-VASc score.

    • “Aspirin is pretty much dead for a fib.”

      • It used to be that patients with AF and a low CHADS2-VASc  score were started on aspirin. Those with a higher score were put on anticoagulation.

      • Numerous studies have demonstrated that aspirin is not the right choice for patients with a CHADS2-VASc score greater than 2. Despite this knowledge, a recent study showed that a third of more than 200,000 patients in the PINNACLE registry were prescribed aspirin alone for a CHADS2-VASc score of two or more.

        • Hsu, Jonathan C., et al. "Oral anticoagulant prescription in patients with atrial fibrillation and a low risk of thromboembolism: insights from the NCDR PINNACLE Registry." JAMA internal medicine 175.6 (2015): 1062-1065. PMID: 25867280

      • Patients with non-valvular AF and a CHADS2-VASc score of zero require no anticoagulation at all.

      • The controversy lies in what anticoagulant to use for patients with a score of one.  This is where the real risk-benefit analysis becomes so important.

        • Aspirin has not shown benefit for the risk of stroke in AF.

        • Aspirin has been shown to be harmful, with a bleeding risk greater than warfarin!

          • A study of 4000 low-risk patients after ablation for AF found no benefit from long-term aspirin therapy. The rates of GI and GU bleeding were significantly higher for those receiving aspirin compared with no therapy and with warfarin.

            • Jacobs, Victoria, et al. "Long‐term aspirin does not lower risk of stroke and increases bleeding risk in low‐risk atrial fibrillation ablation patients." Journal of cardiovascular electrophysiology 28.11 (2017): 1241-1246. PMID: 28845890

          • Another study of 39,000 Danish patients with non-valvular AF and a CHADS2-VASc score of zero or one showed no reduction in stroke with aspirin compared to no treatment. In addition, there was a significant increase in bleeding for patients with just one risk factor.

            • Lip, Gregory YH, et al. "Oral anticoagulation, aspirin, or no therapy in patients with nonvalvular AF with 0 or 1 stroke risk factor based on the CHA2DS2-VASc score." Journal of the American College of Cardiology 65.14 (2015): 1385-1394. PMID: 25770314 Full Text

      • Is aspirin a reasonable substitute for patients with AF and a higher CHADS2-VASc score who refuse warfarin and DOACs?  No.

        • For these patients, the overwhelming evidence has shown that aspirin will not prevent stroke.

        • Substituting aspirin will not only yield no benefit.  It may also cause harm. “Risk without reward is not a good trade off.”

        • The 2016 European Society of Cardiology Guideline on AF states:  “The bleeding risk on aspirin is not different than the bleeding risk on vitamin K antagonists or NOACs, while vitamin K and NOACs, but not aspirin, effectively prevent strokes in atrial fibrillation patients.”

          • Authors/Task Force Members:, et al. "2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS." EP Europace 18.11 (2016): 1609-1678.  PMID: 27663299

        • The 2014 US guidelines say that for nonvalvular AF patients with a low CHADS-VASc score, you can consider no therapy, an oral anticoagulant, or aspirin.  Importantly, this recommendation was made before the current data mentioned above was available.

          • January, Craig T., et al. "2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society." Journal of the American College of Cardiology 64.21 (2014): e1-e76. PMID: 24685669

Ken S., MD -

Just to mention a fine point. The first dose of suboxone in the ER should be 4mg SL, An hour or so later you can go big , like 16mg. This is because the kappa receptors get antagonized first and people tend to get a little withdrawal from the suboxone even though overall they are in withdrawal. Thanks, Ken Starr MD

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